DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendments
This is a final office action in response to applicant's arguments and remarks filed on 10/14/2025.
Status of Rejections
The objections to the claims are withdrawn in view of applicant’s amendments.
The rejection(s) of claim(s) 8 and 11 is/are obviated by applicant’s cancellation.
All other previous rejections are withdrawn in view of applicant’s amendments.
New grounds of rejection are necessitated by applicant’s amendments.
Claims 1, 5, 7, 10, 13, 15 and 18-24 are pending and under consideration for this Office Action.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 24 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 24 recites the limitation "the photoanode layer" in line 2. There is insufficient antecedent basis for this limitation in the claim. The limitation of there being two “photoanode layers”, i.e. one photoanode layer for each of the two plate-type photoelectrodes, is previously introduced in claim 18. It is therefore unclear which individual photoanode layer is being referred to in the recitation of claim 24. For examination purposes, this limitation has been interpreted to refer to each of the photoanode layers.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 5, 13, 15 and 19-21 are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. (“New BiVO4 Dual Photoanodes with Enriched Oxygen Vacancies for Efficient Solar-Driven Water Splitting”, Adv. Mater., 2018) in view of Arakawa et al. (JP 2008251517 A, citations based on translation), and further in view of Kim et al. (“Hetero-type dual photoanodes for unbiased solar water splitting with extended light harvesting” and Supplementary Information thereof, Nat Commun, 2016), Han et al. (“Boosting the solar water oxidation performance of a BiVO4 photoanode by crystallographic orientation control” and Supplementary Information, Energy Environ. Sci., 2018), Ono et al. (U.S. 2015/0252483) and Winz et al. (“Novel light-trapping schemes involving planar junctions and diffuse rear reflectors for thin-film silicon-based solar cells”, Solar Energy Materials and Solar Cells-, 1997).
Regarding claims 1 and 19-20, Wang teaches a photoelectrochemical photoelectrode for water splitting (see e.g. connecting paragraph of Pages 1-2, lines 4-13), which comprises a plate-type photoelectrode comprising a transparent electrode substrate and a photoanode layer disposed on the transparent electrode substrate (see e.g. Figs 1a and 4a, Page 2, Col. 1, lines 4-7, plate-type photoanodes of BiVO4 films on FTO glass substrate), wherein the photoelectrochemical photoelectrode comprises two plate-type photoelectrodes, and the two plate-type photoelectrodes are spaced apart from each other by a predetermined interval so that they may be disposed face-to-face (see e.g. Fig. 4a, two plate-type photoanodes stacked one behind the other; Page 2, Col. 2, 2nd paragraph, lines 19-22, and Page 5, Col. 1, bottom paragraph, lines 1-4),
wherein each of the two plate type photoelectrode has an area of 2.68 cm2 or 6.70 cm2 (see e.g. Fig. 1a, overall glass dimensions of ~46.4mm by 14.5 mm based on ruler scale, resulting in an area of 6.70 cm2, and BVO photoanode region dimensions of ~18.5mm by 14.5mm, resulting in an area of 2.68 cm2), and
wherein each photoanode layer comprises bismuth vanadate (BiVO4) (see e.g. Page 2, Col. 1, line 4).
Wang does not teach the photoanode layer having a ratio of width and length of 1:25-1:50, but does teach it being rectangular, with a smaller width than length (see e.g. Fig. 1a, rectangular yellow BVO photoanode layers).
Arakawa teaches a photoelectrode (see e.g. Paragraph 0001) with a rectangular working electrode region with a width of 0.5 to 2 cm and a length of 4.5 to 30 cm (see e.g. Paragraph 0044), which equates to a width to length ratio of 1:2.25 to 1:60 and area of 2.25 to 60 cm2, overlapping or falling within the claimed ranges of the present invention.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the photoanode layer of Wang to have a width of 0.5 to 2 cm and a length of 4.5 to 30 cm, resulting in a width to length ratio of 1:2.25 to 1:60 and area of 2.25 to 60 cm2 as taught by Arakawa as suitable dimensions for the working area of a rectangular photoelectrode. MPEP § 2144.05 I states “In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists.” Further, MPEP § 2143(I)(A) states that “combining prior art elements according to known methods to yield predictable results” may be obvious. The claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination would yield nothing more than predictable results.
Modified Wang does not teach the photoanode layers disposed on each of the two plate-type photoelectrodes having different thicknesses, wherein a front photoanode layer of the photoanode layers receiving light irradiation has a thickness of 50-200 nm, and a rear photoanode layer of the photoanode layers has a thickness of 600-1500 nm, instead teaching both photoanode layers having a thickness of 250 nm (see e.g. Wang Page 2, Col. 2, lines 20-23, thickness of BVO-1.5h films which form the dual photoanode).
Kim teaches a dual photoelectrode (see e.g. Abstract) comprising a BiVO4 photoanode in front of a Fe2O3 photoanode (see e.g. Fig. 2a), wherein photocurrent can be optimized by adjusting the thickness of the two photoanode layers (see e.g. Page 3, Col. 1, 3rd paragraph, lines 13-15), increase of thickness resulting in increased light harvesting efficiency (LHE), though significant increase of the front photoanode deters transmittance to the underlying photoanode (see e.g. caption of Supplementary Fig. 11).
Though the photoanodes of Kim are different materials, Han similarly teaches BiVO4 photoanodes (see e.g. Abstract) with BiVO4 layers having thicknesses in the range of 200 nm to 1500 nm, with specific examples of 200 nm and 800 nm (see e.g. Figs. 3c and S7, thicknesses of p-BVO films), overlapping and falling within the claimed ranges of the present invention(see MPEP § 2144.05 I as cited above), with a trend of increased thickness equating to increased photocurrent density from 200 to 800 nm (see e.g. Fig. 3c, Table S1 and Page 1302, Col. 2, lines 7-11).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the BiVO4 photoanode layers of modified Wang to have individually optimized thicknesses within a range such as 200 nm to 1500 or 800 nm, particularly with a thicker rear photoanode, as taught by Kim and Han to improve photocurrent density and light harvesting efficiency. MPEP § 2144.05 II states “"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955)”. The relative thicknesses of the BiVO4 photoanode layers is a results-effective variable influencing photocurrent density and light harvesting efficiency as taught by Kim and Han above.
Modified Wang does not teach the photoelectrochemical photoelectrode for water splitting further comprising a reflector which reflects the light transmitted through all of the plate-type photoelectrodes toward a rear photoelectrode opposite to a front photoelectrode receiving light irradiation directly, upon the light irradiation, wherein the reflector is disposed in the shape of a plate along one side of the rear photoelectrode. Wang does teach the plural photoelectrodes being stacked one behind another such that a front photoelectrode is directly irradiated (see e.g. Wang Fig. 4a, top BVO photoanode directly irradiated with bottom BVO behind it).
Ono teaches a photoelectrochemical device (see e.g. Paragraph 0047) comprising several photoactive layers provided on a transparent substrate (see e.g. Fig. 1, photovoltaic cells 14, 15 and 16 on reduction electrode layer 13 which comprises transparent conductive materials; Paragraph 0051, lines 10-14, and Paragraph 0052, lines 1-4) and a reflecting layer provided at the rear of the substrate respective to transmission of light (see e.g. Fig. 1, reflecting layer 12 at the rear with respect to the light incidence surface; Paragraph 0050, lines 1-2), so that light not absorbed during initial transmission through the photoactive layers is reflected from the rear and re-enters the photoactive layers, thereby improving the light absorption rate (see e.g. Paragraph 0050, lines 5-11), the reflector being disposed in the shape of a plate along one side of the rear photoelectrode (see e.g. Fig. 1, reflecting layer 12 at rear of photovoltaic cells 14, 15 and 16).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the photoelectrode of modified Wang to comprise a plate-shaped reflecting layer at a rear side of the rear photoelectrode such that light transmitted through the plural photoelectrodes is reflected back toward the rear photoelectrode as taught by Ono to improve the light absorption rate.
Modified Wang does not explicitly teach the reflector being installed to form an angle of 8-12° with the rear photoelectrode. Ono further teaches the angle of a rear reflector being varied to change the amount of incident light (see e.g. Ono Paragraph 0247, lines 1-4, and Paragraph 0272, lines 9-14), allowing for improvement of photoelectrochemical reaction efficiency (see e.g. Ono Paragraph 0272, lines 14-16).
Winz teaches a solar cell (see e.g. Abstract) including a rear reflector which is formed at an angle of 11° with respect to the planar solar cell (see e.g. Fig. 2c), this angle providing increased absorption without cone loss (see e.g. connecting paragraph of Pages 201-202, lines 1-5).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the reflector of modified Wang to be installed to form an angle of 11° with the rear photoelectrode as taught by Winz as a rear reflector angle which provides increased solar absorption without cone loss.
Regarding claim 5, Wang as modified by Ono teaches the reflector comprising metals (see e.g. Ono Paragraph 0050, lines 2-4).
Regarding claim 13, modified Wang teaches the transparent electrode substrate being FTO (see e.g. Wang Page 2, Col. 1, lines 6-7).
Regarding claim 15, modified Wang teaches a water splitting apparatus comprising the photoelectrochemical photoelectrode for water splitting as defined in claim 1 (see e.g. Wang Fig. 4a, water splitting device; Page 5, Col. 1, bottom paragraph, lines 1-4).
Regarding claim 21, modified Wang teaches each photoanode layer being bismuth vanadate (BiVO4) (see e.g. Wang Page 2, Col. 1, line 4).
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, Arakawa, Kim, Han, Ono and Winz, as applied to claim 1 above, and further in view of Kuang et al. (“A Front-Illuminated Nanostructured Transparent BiVO4 Photoanode for >2% Efficient Water Splitting”, Adv. Energy Mater., 2016).
Regarding claim 7, modified Wang teaches all the elements of the photoelectrode of claim 1 as stated above. Modified Wang does not teach the two plate-type photoelectrodes being disposed in such a manner that the surfaces of the transparent electrode substrates having no photoanode layer may face each other, instead teaching the photoanode layer of a front photoelectrode facing the transparent electrode substrate of a rear photoelectrode (see e.g. Wang Fig. 4a), as the back illumination for the BiVO4 photoanode films exhibited better photocurrent densities than the front illumination (see e.g. Wang Page 2, Col. 2, 2nd paragraph, lines 13-17).
Kuang teaches a photoelectrochemical water splitting device (see e.g. Page 1, Col. 2, 2nd paragraph, lines 5-11) comprising a back-to-back stack of BiVO4 photoanodes, wherein the front photoanode is front illuminated, i.e. with the active layer facing the light, allowing for a remarkable photocurrent to be achieved (see e.g. Fig. 1d, Page 3, Col. 1, lines 21-31). The BiVO4 photoanodes have a worm-like network morphology (see e.g. Page 1, Col. 2, last paragraph, lines 1-2), exhibit similar charge separation under front and back illumination, and are thereby able to achieve a higher front illumination photocurrent density than the back illumination which experiences losses due to reflection at the electrolyte/substrate interface (see e.g. Page 3, Col. 1, lines 11-18).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the plate-type photoelectrodes of modified Wang to comprise the worm-like BiVO4 photoanode layers and be placed in a back-to-back configuration as taught by Kuang to enable front-illumination and allow a remarkable photocurrent to be achieved without losses due to reflection at the electrolyte/substrate interface.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, Arakawa, Kim, Han, Ono and Winz, as applied to claim 1 above, and further in view of Diaz et al. (U.S. 2010/0213075).
Regarding claim 10, modified Wang teaches all the elements of the photoelectrode of claim 1 as stated above. Wang does not explicitly teach the two plate-type photoelectrodes being disposed in such a manner that they may be spaced apart from each other by an interval of 0.1-1.0 mm, but does teach the presence of an interval accommodating electrolyte (see e.g. Wang Fig. 4a, O2 generation from water splitting occurring between the two BVO photoanodes), which would necessarily be an interval greater than 0.
Diaz teaches an electrochemical reactor for reactions such as water electrolysis (see e.g. Abstract) comprising a plurality of electrodes with flat parallel faces separated from each other by a distance greater than 0.01 and less than 1 mm (see e.g. Paragraph 0010, lines 3-6, and Paragraph 0043, lines 1-5), overlapping the claimed range of the present invention (see MPEP § 2144.05 I as cited above), the gap between the electrodes being filled with an electrolytic solution (see e.g. Paragraph 0010, lines 6-7).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the two plate-type photoelectrodes of modified Wang to be separated by distance of greater than 0.01 and less than 1 mm as taught by Diaz as a suitable separation gap for accommodating electrolyte between adjacent flat parallel electrodes. MPEP § 2143(I)(A) states that “combining prior art elements according to known methods to yield predictable results” may be obvious. The claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination would yield nothing more than predictable results.
Claims 18 and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Kim, and further in view of Han, Kuang, Jung et al. (DE 102016207350 A1, citations based on translation), Ono and Winz.
Regarding claim 18, Wang teaches a photoelectrochemical photoelectrode for water splitting (see e.g. connecting paragraph of Pages 1-2, lines 4-13), which comprises a plate-type photoelectrode comprising a transparent electrode substrate and a photoanode layer disposed on the transparent electrode substrate (see e.g. Figs 1a and 4a, Page 2, Col. 1, lines 4-7, plate-type photoanodes of BiVO4 films on FTO glass substrate), wherein the photoelectrochemical photoelectrode comprises two plate-type photoelectrodes, and the two plate-type photoelectrodes are spaced apart from each other by a predetermined interval so that they may be disposed face-to-face (see e.g. Fig. 4a, two plate-type photoanodes stacked one behind the other, with respective opposite faces facing each other; Page 2, Col. 2, 2nd paragraph, lines 19-22, and Page 5, Col. 1, bottom paragraph, lines 1-4);
wherein the photoelectrochemical photoelectrode comprises two plate-type photoelectrodes (see e.g. Fig. 4a, two plate-type photoanodes),
wherein the two plate-type photoelectrodes are rectangular plate-type electrodes wherein a length of the plate-type photoelectrode is different from a width of the plate-the photoelectrode (see e.g. Fig. 1a, rectangular yellow BVO photoanode layers with smaller width than length),
wherein each photoanode layer comprises bismuth vanadate (BiVO4) (see e.g. Page 2, Col. 1, line 4), and
wherein the two plate type photoelectrodes are disposed in such a manner that they may be spaced apart from each other by an interval (see e.g. Fig. 4a, space shown between the two BVO photoanodes).
Modified Wang does not teach the photoanode layers disposed on each of the two plate-type photoelectrodes having different thicknesses, wherein a front photoanode layer of the photoanode layers receiving light irradiation has a thickness of 50-200 nm, and a rear photoanode layer of the photoanode layers has a thickness of 600-1500 nm, instead teaching both photoanode layers having a thickness of 250 nm (see e.g. Wang Page 2, Col. 2, lines 20-23, thickness of BVO-1.5h films which form the dual photoanode).
Kim teaches a dual photoelectrode (see e.g. Abstract) comprising a BiVO4 photoanode in front of a Fe2O3 photoanode (see e.g. Fig. 2a), wherein photocurrent can be optimized by adjusting the thickness of the two photoanode layers (see e.g. Page 3, Col. 1, 3rd paragraph, lines 13-15), increase of thickness resulting in increased light harvesting efficiency (LHE), though significant increase of the front photoanode deters transmittance to the underlying photoanode (see e.g. caption of Supplementary Fig. 11).
Though the photoanodes of Kim are different materials, Han similarly teaches BiVO4 photoanodes (see e.g. Abstract) with BiVO4 layers having thicknesses in the range of 200 nm to 1500 nm, with specific examples of 200 nm and 800 nm (see e.g. Figs. 3c and S7, thicknesses of p-BVO films), overlapping and falling within the claimed ranges of the present invention(see MPEP § 2144.05 I as cited above), with a trend of increased thickness equating to increased photocurrent density from 200 to 800 nm (see e.g. Fig. 3c, Table S1 and Page 1302, Col. 2, lines 7-11).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the BiVO4 photoanode layers of modified Wang to have individually optimized thicknesses within a range such as 200 nm to 1500 or 800 nm, particularly with a thicker rear photoanode, as taught by Kim and Han to improve photocurrent density and light harvesting efficiency. MPEP § 2144.05 II states “"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955)”. The relative thicknesses of the BiVO4 photoanode layers is a results-effective variable influencing photocurrent density and light harvesting efficiency as taught by Kim and Han above.
Modified Wang does not teach the two plate-type photoelectrodes being disposed in such a manner that the surfaces of the transparent electrode substrates having no photoanode layer may have each other, instead teaching the photoanode layer of a front photoelectrode facing the transparent electrode substrate of a rear photoelectrode (see e.g. Wang Fig. 4a), as the back illumination for the BiVO4 photoanode films exhibited better photocurrent densities than the front illumination (see e.g. Wang Page 2, Col. 2, 2nd paragraph, lines 13-17).
Kuang teaches a photoelectrochemical water splitting device (see e.g. Page 1, Col. 2, 2nd paragraph, lines 5-11) comprising a back-to-back stack of BiVO4 photoanodes, wherein the front photoanode is front illuminated, i.e. with the active layer facing the light, allowing for a remarkable photocurrent to be achieved (see e.g. Fig. 1d, Page 3, Col. 1, lines 21-31). The BiVO4 photoanodes have a worm-like network morphology (see e.g. Page 1, Col. 2, last paragraph, lines 1-2), exhibit similar charge separation under front and back illumination, and are thereby able to achieve a higher front illumination photocurrent density than the back illumination which experiences losses due to reflection at the electrolyte/substrate interface (see e.g. Page 3, Col. 1, lines 11-18).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the plate-type photoelectrodes of modified Wang to comprise the worm-like BiVO4 photoanode layers and be placed in a back-to-back configuration as taught by Kuang to enable front-illumination and allow a remarkable photocurrent to be achieved without losses due to reflection at the electrolyte/substrate interface.
Wang in view of Kuang does not explicitly teach interval between the two plate-type photoelectrodes being 0.1-1.0 mm.
Jung teaches a photoelectrolytic cell comprising at least two photoelectrodes arranged one behind the other (see e.g. Paragraphs 0024-0025), wherein the photoelectrodes are separated by distances of 0.02 to 0.5 mm to optimally reduce scaling losses (see e.g. Paragraph 0058, lines 1-3), with slightly larger distances greater than 0.1 mm potentially proving more relevant in practice or more efficient overall from optical evaluations and flow-related considerations (see e.g. Paragraph 0058, lines 3-5).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the interval between the two plate-type photoelectrodes to be between 0.1 and 0.5 mm as taught by Jung as an optimal photoelectrode distance range for reducing scaling losses which may prove more relevant in practice or more efficient overall from optical evaluations and flow-related considerations.
Modified Wang does not teach the photoelectrochemical photoelectrode for water splitting further comprising a reflector which reflects the light transmitted through all of the plural plate-type photoelectrodes toward a rear photoelectrode opposite to a front photoelectrode receiving light irradiation directly, upon the light irradiation, wherein the reflector is disposed in the shape of a plate along one side of the rear photoelectrode. Wang does teach the plural photoelectrodes being stacked one behind another such that a front photoelectrode is directly irradiated (see e.g. Wang Fig. 4a, top BVO photoanode directly irradiated with bottom BVO behind it).
Ono teaches a photoelectrochemical device (see e.g. Paragraph 0047) comprising several photoactive layers provided on a transparent substrate (see e.g. Fig. 1, photovoltaic cells 14, 15 and 16 on reduction electrode layer 13 which comprises transparent conductive materials; Paragraph 0051, lines 10-14, and Paragraph 0052, lines 1-4) and a reflecting layer provided at the rear of the substrate respective to transmission of light (see e.g. Fig. 1, reflecting layer 12 at the rear with respect to the light incidence surface; Paragraph 0050, lines 1-2), so that light not absorbed during initial transmission through the photoactive layers is reflected from the rear and re-enters the photoactive layers, thereby improving the light absorption rate (see e.g. Paragraph 0050, lines 5-11), the reflector being disposed in the shape of a plate along one side of the rear photoelectrode (see e.g. Fig. 1, reflecting layer 12 at rear of photovoltaic cells 14, 15 and 16).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the photoelectrode of modified Wang to comprise a plate-shaped reflecting layer at a rear side of the rear photoelectrode such that light transmitted through the plural photoelectrodes is reflected back toward the rear photoelectrode as taught by Ono to improve the light absorption rate.
Modified Wang does not explicitly teach the reflector being installed to form an angle of 8-12° with the rear photoelectrode. Ono further teaches the angle of a rear reflector being varied to change the amount of incident light (see e.g. Ono Paragraph 0247, lines 1-4, and Paragraph 0272, lines 9-14), allowing for improvement of photoelectrochemical reaction efficiency (see e.g. Ono Paragraph 0272, lines 14-16).
Winz teaches a solar cell (see e.g. Abstract) including a rear reflector which is formed at an angle of 11° with respect to the planar solar cell (see e.g. Fig. 2c), this angle providing increased absorption without cone loss (see e.g. connecting paragraph of Pages 201-202, lines 1-5).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the reflector of modified Wang to be installed to form an angle of 11° with the rear photoelectrode as taught by Winz as a rear reflector angle which provides increased solar absorption without cone loss.
Regarding claim 22, modified Wang teaches each photoanode layer being bismuth vanadate (BiVO4) (see e.g. Wang Page 2, Col. 1, line 4).
Claim 24 is rejected under 35 U.S.C. 103 as being unpatentable over Wang, Kim, Han, Kuang, Jung, Ono and Winz, as applied to claim 18 above, and further in view of Arakawa.
Regarding claim 24, modified Wang teaches all the elements of the photoelectrochemical photoelectrode of claim 18 as stated above. Modified Wang does not teach the photoanode layer having a ratio of width and length of 1:25-1:50, but does teach it being rectangular, with a smaller width than length (see e.g. Fig. 1a, rectangular yellow BVO photoanode layers).
Arakawa teaches a photoelectrode (see e.g. Paragraph 0001) with a rectangular working electrode region with a width of 0.5 to 2 cm and a length of 4.5 to 30 cm (see e.g. Paragraph 0044), which equates to a width to length ratio of 1:2.25 to 1:60 overlapping the claimed range of the present invention (see MPEP § 2144.05 I as cited above).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the photoanode layer of Wang to have a width of 0.5 to 2 cm and a length of 4.5 to 30 cm, resulting in a width to length ratio of 1:2.25 to 1:60, as taught by Arakawa as suitable dimensions for the working area of a rectangular photoelectrode. MPEP § 2143(I)(A) states that “combining prior art elements according to known methods to yield predictable results” may be obvious. The claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination would yield nothing more than predictable results.
Claim 23 is rejected under 35 U.S.C. 103 as being unpatentable over Wang in view of Xu et al. (“A graphene oxide–molecular Cu porphyrin-integrated BiVO4 photoanode for improved photoelectrochemical water oxidation performance”, J. Mater. Chem. A, Jan 2020), and further in view of Kim, Han, Ono and Winz.
Regarding claim 23, Wang teaches a photoelectrochemical photoelectrode for water splitting (see e.g. connecting paragraph of Pages 1-2, lines 4-13), which comprises a plate-type photoelectrode comprising a transparent electrode substrate and a photoanode layer disposed on the transparent electrode substrate (see e.g. Figs 1a and 4a, Page 2, Col. 1, lines 4-7, plate-type photoanodes of BiVO4 films on FTO glass substrate), wherein the photoelectrochemical photoelectrode comprises two plate-type photoelectrodes, and the two plate-type photoelectrodes are spaced apart from each other by a predetermined interval so that they may be disposed face-to-face (see e.g. Fig. 4a, two plate-type photoanodes stacked one behind the other; Page 2, Col. 2, 2nd paragraph, lines 19-22, and Page 5, Col. 1, bottom paragraph, lines 1-4).
Wang does not teach the photoanode layer having a ratio of width and length of 1:1, wherein each of the two plate-type photoelectrodes has an area of at most 1 cm2.
Xu teaches a BiVO4 photoanode (see e.g. Abstract and Scheme 1) with size of 1x1 cm2 acting as the working electrode in a photoelectrochemical cell (see e.g. connecting paragraph of Pages 4063-4064, lines 1-6).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the photoanode layer of Wang to have dimensions of 1x1 cm, forming a 1 cm2 photoelectrode, as taught by Xu as suitable dimensions for the working area of a bismuth vanadate photoanode. MPEP § 2143(I)(A) states that “combining prior art elements according to known methods to yield predictable results” may be obvious. The claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination would yield nothing more than predictable results.
Modified Wang does not teach the photoanode layers disposed on each of the two plate-type photoelectrodes having different thicknesses, wherein a front photoanode layer of the photoanode layers receiving light irradiation has a thickness of 50-200 nm, and a rear photoanode layer of the photoanode layers has a thickness of 600-1500 nm, instead teaching both photoanode layers having a thickness of 250 nm (see e.g. Wang Page 2, Col. 2, lines 20-23, thickness of BVO-1.5h films which form the dual photoanode).
Kim teaches a dual photoelectrode (see e.g. Abstract) comprising a BiVO4 photoanode in front of a Fe2O3 photoanode (see e.g. Fig. 2a), wherein photocurrent can be optimized by adjusting the thickness of the two photoanode layers (see e.g. Page 3, Col. 1, 3rd paragraph, lines 13-15), increase of thickness resulting in increased light harvesting efficiency (LHE), though significant increase of the front photoanode deters transmittance to the underlying photoanode (see e.g. caption of Supplementary Fig. 11).
Though the photoanodes of Kim are different materials, Han similarly teaches BiVO4 photoanodes (see e.g. Abstract) with BiVO4 layers having thicknesses in the range of 200 nm to 1500 nm, with specific examples of 200 nm and 800 nm (see e.g. Figs. 3c and S7, thicknesses of p-BVO films), overlapping and falling within the claimed ranges of the present invention(see MPEP § 2144.05 I as cited above), with a trend of increased thickness equating to increased photocurrent density from 200 to 800 nm (see e.g. Fig. 3c, Table S1 and Page 1302, Col. 2, lines 7-11).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the BiVO4 photoanode layers of modified Wang to have individually optimized thicknesses within a range such as 200 nm to 1500 or 800 nm, particularly with a thicker rear photoanode, as taught by Kim and Han to improve photocurrent density and light harvesting efficiency. MPEP § 2144.05 II states “"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955)”. The relative thicknesses of the BiVO4 photoanode layers is a results-effective variable influencing photocurrent density and light harvesting efficiency as taught by Kim and Han above.
Modified Wang does not teach the photoelectrochemical photoelectrode for water splitting further comprising a reflector which reflects the light transmitted through all of the plate-type photoelectrodes toward a rear photoelectrode opposite to a front photoelectrode receiving light irradiation directly, upon the light irradiation, wherein the reflector is disposed in the shape of a plate along one side of the rear photoelectrode. Wang does teach the plural photoelectrodes being stacked one behind another such that a front photoelectrode is directly irradiated (see e.g. Wang Fig. 4a, top BVO photoanode directly irradiated with bottom BVO behind it).
Ono teaches a photoelectrochemical device (see e.g. Paragraph 0047) comprising several photoactive layers provided on a transparent substrate (see e.g. Fig. 1, photovoltaic cells 14, 15 and 16 on reduction electrode layer 13 which comprises transparent conductive materials; Paragraph 0051, lines 10-14, and Paragraph 0052, lines 1-4) and a reflecting layer provided at the rear of the substrate respective to transmission of light (see e.g. Fig. 1, reflecting layer 12 at the rear with respect to the light incidence surface; Paragraph 0050, lines 1-2), so that light not absorbed during initial transmission through the photoactive layers is reflected from the rear and re-enters the photoactive layers, thereby improving the light absorption rate (see e.g. Paragraph 0050, lines 5-11), the reflector being disposed in the shape of a plate along one side of the rear photoelectrode (see e.g. Fig. 1, reflecting layer 12 at rear of photovoltaic cells 14, 15 and 16).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the photoelectrode of modified Wang to comprise a plate-shaped reflecting layer at a rear side of the rear photoelectrode such that light transmitted through the plural photoelectrodes is reflected back toward the rear photoelectrode as taught by Ono to improve the light absorption rate.
Modified Wang does not explicitly teach the reflector being installed to form an angle of 8-12° with the rear photoelectrode. Ono further teaches the angle of a rear reflector being varied to change the amount of incident light (see e.g. Ono Paragraph 0247, lines 1-4, and Paragraph 0272, lines 9-14), allowing for improvement of photoelectrochemical reaction efficiency (see e.g. Ono Paragraph 0272, lines 14-16).
Winz teaches a solar cell (see e.g. Abstract) including a rear reflector which is formed at an angle of 11° with respect to the planar solar cell (see e.g. Fig. 2c), this angle providing increased absorption without cone loss (see e.g. connecting paragraph of Pages 201-202, lines 1-5).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the reflector of modified Wang to be installed to form an angle of 11° with the rear photoelectrode as taught by Winz as a rear reflector angle which provides increased solar absorption without cone loss.
Response to Arguments
Applicant’s arguments, see page 8, filed 10/14/2025, with respect to the rejection(s) of amended claim(s) 1 under 35 USC 103 over Wang in view of Arakawa, Kim, Xiao, Ono and Winz, particularly regarding the thicknesses of the photoanode layers, have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Wang, Arakawa, Kim, Han, Ono and Winz.
Applicant’s arguments, see page 9, filed 10/14/2025, with respect to the rejection(s) of amended claim(s) 18 under 35 USC 103 over Wang in view of Kim, Xiao, Kuang, Jung, Ono and Winz, particularly regarding the thicknesses of the photoanode layers, have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Wang, Kim, Han, Kuang, Jung, Ono and Winz.
Applicant’s arguments, see page 10, filed 10/14/2025, with respect to the rejection(s) of amended claim(s) 23 under 35 USC 103 over Wang in view of Xu, Kim, Xiao, Ono and Winz, particularly regarding the thicknesses of the photoanode layers, have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Wan, Xu, Kim, Han, Ono and Winz.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/M.S.J./Examiner, Art Unit 1795
/LUAN V VAN/Supervisory Patent Examiner, Art Unit 1795