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 Amendment
The amendment filed on 4 June 2026 has been entered. Claims 1-4 and 6-10 remain pending in the application, each of which has been amended. Claim 5 has been canceled by the Applicants. Claims 11-15 have been added in the amendment. The previous rejection of originally-filed claims 1-10 under 35 U.S.C. §112(b) are withdrawn in light of the amendments to the claims. All previous prior art grounds of rejection are withdrawn in light of amendments to the claims. New grounds of rejection are presented herein.
Response to Arguments
Applicants’ arguments filed 4 June 2026 have been fully considered but they are not persuasive.
In response to Applicants’ argument that Domen does not teach reusing a metal substrate, the teaching relied upon is reuse of the substrate on which the electrode is formed, not that it is metallic; the metallic substrate is taught by Ichinose at col. 23, lines 4-15 as relied upon in the previous 35 U.S.C. § 103 rejections. The most relevant section of the previously cited Domen col. 10, lines 48-52 reads:
“However, from the viewpoint that the possibility of any damage to the photocatalyst layer 12a is low, or from the viewpoint that reutilization of the first substrate 20 can be implemented, a method of mechanically detaching the first substrate 20 is preferred.” (emphasis added)
Additionally, the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985).
In response to Applicants’ argument that Shinde and He do not teach reusing a metal substrate, these are not the teachings relied upon and applied to claims 3 and 8-10 (Shinde) or claim 6 (He). The reuse of a metal substrate is taught by the combination of Domen and Ichinose as applied to the originally-filed claims 1 and 2 in the previous office action.
Consequently, for at least these reasons, the Examiner finds the Applicants’ arguments unpersuasive.
Claim Objections
Claim 13 is objected to because of the following informalities: "further comprises" should read "further comprising." Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
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.
Claims 2, 3, and 8-12 are rejected under 35 U.S.C. 112(a) as failing to comply with the written description requirement. The claims contain subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor had possession of the claimed invention at the time the application was filed.
Regarding claims 2, 3, and 8-10, a “failed electrode” is discussed in [0058] as one example embodiment of the claimed invention. However, the disclosure fails to define a failed electrode as is it relevant to the rest of the disclosure, which is more generally applied to reuse of a substrate. Therefore, the limitations directed to the failed electrode must be cancelled from the claims.
Claims 11 and 12 are further rejected because they inherit all limitations of rejected claim 8 on which they depend.
Claim 12 is rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor regards as the invention.
Regarding claim 12, it is unclear as claimed if the chemical treatments are being listed in the alternative or required together. It is also unclear how the metals "aluminum," "brass," "copper," "mild steel," and "stainless steel" relate to the chemical treatments. By [0056] of the specification, these will be understood to refer to chemical treatments which are claimed for use with specific metal surfaces, and that the chemical treatments are listed in the alternative. However, there is also insufficient antecedent basis for these limitations in the claim. These listed metals will be understood to refer to the metal substrate of claims 8 and 1 on which it depends.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 2, 4, 6, 7, and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Domen et al. (US 10,337,112 B2) in view of Ichinose (US 5,681,402 A) and He et al. (US 2020/0056289 A1).
Regarding claims 1, 2, and 4, Domen teaches a process for using a substrate for photoelectrochemical water splitting (Col. 2, lines 14-19). The process comprises preparing a substrate surface by obtaining adequate surface finish and cleaning (Col. 5, lines 7-9: as polishing/cleaning treatment), coating the cleaned surface of the substrate with a layer of electrode material (Col. 6, lines 14-23 and 53-65), forming a working electrode and scaling it to the desired thickness (Col. 5, lines 10-42: as electroplating or coating methods, liquid/vapor phase growing), and reuse of the substrate (Col. 10, lines 48-52).
Domen does not teach that the conductive substrate is metal, but suggests that the conductivity of the substrate improves its reusability (Col. 1, lines 47-65); nor that electrode material is placed on the substrate as a photocatalyst, instead requiring a later step for conversion to a semiconductive layer (Col. 6, lines 42-52); nor coating two active surfaces to obtain a bifacially coated working electrode; nor that the preparation of the reusable metal substrate comprises obtaining an adequate surface finish of, specifically, a failed electrode, followed by cleaning the failed electrode.
However, Ichinose teaches preparing a photovoltaic element on a metal substrate (Col. 23, lines 4-15; Fig 4a, element 401 substrate). Ichinose also teaches that the substrate may be silicon as it is disclosed in Domen (Ichinose Col. 17, lines 28-33; Fig 5, element 501), and that transition metal oxides may serve as semiconductor layers (Col. 18, lines 26-34). The inventions are analogous because the deposited layers are photoactive semiconductors.
Additionally, He teaches bifacial PEC cells for water splitting, comprising two photoactive semiconductor layers on opposite sides of a substrate ([0055], [0069]; photoactive as "light harvesting").
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have substituted the Domen substrate with a metallic one as Ichinose teaches and apply a metal oxide layer instead of a metal layer (requiring later treatment) to form the electrode. It would have also been obvious to modify the PEC cell disclosed by Domen and Ichinose by coating both sides of the planar metal substrate with a semiconductor layer as He teaches. One would have been motivated to make these modifications to simplify the process of making the electrode by removing the need for a metal layer and the subsequent oxidation step to make it semiconductive (Domen Col. 5, lines 10-16; Col. 6, lines 14-23), and to improve the current density of the cell and therefore power conversion efficiency compared to a cell with a single-sided photoelectrode (He [0078]). Furthermore, one skilled in the art would have recognized that the process of preparing the reusable metal substrate taught by the combination of Domen, Ichinose and He is not precluded from application to a failed electrode. There is no aspect of the process as taught that requires its application to an electrode which is specifically working or failed. Because an electrode is either working for its intended use or failed, it is obvious to apply the same processes taught by Domen, Ichinose, and He to either type of electrode, because the genus is sufficiently small and well-established in the art. See MPEP §2144.08.
Regarding claim 6, Domen in view of Ichinose does not directly teach that the photoelectrode formed comprises photoanode or photocathode. However, He et al. teaches that the electrode of a photoelectrochemical device must function either as a photoanode or photocathode when part of a water-splitting photoelectrochemical cell ([0060]). Therefore, the working electrode as claimed necessarily comprises a photoanode or a photocathode.
Regarding claim 7, Domen as modified by Ichinose and He does not teach synthesizing a bifacially coated working electrode with a size of 4 cm2. However, the size of the electrode which can be produced is obvious to one skilled in the art through routine experimentation and the parameters of the process used to create it, such as the physical size of the process equipment. It is not inventive to discover the optimal size in this manner. See MPEP §2144.05(II). The size of 4 cm2 as claimed would have been obvious through such routine experimentation.
Regarding claim 13, Domen as modified by Ichinose and He does not teach synthesizing a working electrode with size up to 100 cm2. However, the maximum size of the electrode which can be produced is obvious to one skilled in the art through routine experimentation and the parameters of the process used to create it, such as the physical size of the process equipment. It is not inventive to discover the maximum size in this manner. See MPEP §2144.05(II). The range of “up to 100 cm2” as claimed would have been obvious through such routine experimentation.
Claims 3, 8-11, and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Domen in view of Ichinose and He as applied to claims 1 and 2 above, and further in view of Shinde et al. (US 2019/0233953 A1).
Regarding claim 3, modified Domen teaches all inherited limitations from claims 1 and 2 on which it depends, and also teaches the process of cleaning the failed electrode/substrate with ultrasonic baths of acetone, 2-propanol (isopropanol), and water; for 10 minutes each (Col. 14, lines 24-26). Domen does not teach that the cleaning steps are 15 minutes each, that the water is deionized, or that a drying step is carried out after the wet cleaning processes. However, it is obvious for one skilled in the art to clean the substrate for a longer time such as 15 minutes in each solvent, with the expected outcome of improving the final surface characteristics of the substrate prior to its coating.
In addition, Shinde teaches that a substrate for use in a photoelectrochemical water splitting electrode may be cleaned in successive ultrasonic baths of acetone, ethanol, and deionized water for 10 minutes each, then dried with a nitrogen gas stream, equivalent to an inert gas as claimed ([0128]). It is therefore obvious to one skilled in the art to dry the substrate with an inert gas after washing and before coating, as it is a known process step in preparing substrates for coating. Doing so is known in the art to improve the coating, as residual liquid and dust is removed from the substrate.
Regarding claims 8, 9, and 10, modified Domen teaches all inherited limitations from claim 3, and that mechanically detaching the substrate from the photocatalyst layer allows for its reuse (Domen col. 10, lines 50-52). Domen does not teach details of how the substrate is cleaned prior to its reuse. However, it is obvious to repeat the previously taught cleaning steps from both Domen and Shinde to the metal substrate following mechanical removal of the working electrode, with the expected outcome of removing any remaining used material from the metal substrate. Specifically, these steps involve primary cleaning, as mechanical removal of a thin film coating (Domen Col. 10, lines 50-52; col. 15, lines 14-19) and secondary cleaning and chemical treatment by ultrasonic baths (Col. 14, lines 24-26). Furthermore, Ichinose teaches the use of chemical etching on a substrate to remove undesired portions of an oxide coating (col. 65, lines 53-61). It would have been obvious to include such a step to remove weakly bonded oxides from the failed electrode, as Ichinose shows that the etching is useful in removing undesirable parts of the electrode, which may include any weakly bonded components. It is also obvious for one skilled in the art to optimize this process for minimal loss of substrate material while removing used semiconductor material.
Regarding claim 11, Shinde further teaches that the cleaning process which removes surface coatings from the failed electrode includes detergent cleaning prior to the acetone, ethanol, and deionized water baths ([0128]). It is therefore obvious to include a step of cleaning the failed electrode using detergent. One skilled in the art would expect superior cleanliness of the substrate from adding a detergent cleaning step, as it is a known step for removing additional dirt, dust, or surface coating.
Regarding claim 14, Shinde teaches that the coated electrode can have a photocurrent density of between 2.0 mA cm-2 and 20 mA cm-2-, which includes the claimed 2 mA cm-2 average photocurrent density and 18.04 mA cm-2 average dark current density ([0111]-[0112]). While this range does not include the claimed 20.05 mA cm-2-- light current, the value is similar to the upper limit of the range taught such that one skilled in the art could reasonably expect to obtain such a value from experimental results/measurements of the light current from carrying out the electrode preparation steps taught by the combination of Domen, Ichinose, He, and Shinde.
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Domen et al. (US 10,337,112 B2) in view of Ichinose (US 5,681,402 A), He et al. (US 2020/0056289 A1), and Shinde et al. (US 2019/0233953 A1) as applied to claim 8 above, and further in view of Visintin et al. (WO 2008/121952 A1, as attached).
Regarding claim 12, Domen as modified by Ichinose, He, and Shinde do not teach any of the claimed chemical treatments in the etching step. The etching paste of Ichinose is ferric chloride (col. 65, lines 56-61).
However, Visintin teaches processes for the removal of material layers from a substrate such that the substrate can be reused ([0001]), including with the use of etchants such as a solution comprising HF, HNO3, and water ([0051]: etchant HF [0054], additional acid is nitric acid [0059]). The etchant may be used in removing oxides from the substrate ([0050]).
It would have been obvious to one of ordinary skill in the art to use an etching solution taught by Visintin in the chemical treatment process of Domen, Ichinose, He, and Shinde. One would use such a solution in the chemical treatment step of claim 8 because it is able to remove oxides from the substrate to enable its reuse.
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Domen et al. (US 10,337,112 B2) in view of Ichinose (US 5,681,402 A) and He et al. (US 2020/0056289 A1) as applied to claim 1 above, and further in view of Ozin et al. (US 2013/0168228 A1).
Regarding claim 15, Domen as modified by Ichinose and He teaches all inherited limitations from claim 1. Modified Domen does not teach coating the two active surfaces with Co3O4.
However, Ozin teaches a photoactive material comprising Co3O4- coated onto a metal substrate ([0163], [0171]: Co3O4 is a suitable photoactive constituent, see also claim 18; [0321]-[0323]: substrate with photoactive material coated onto it). CO3O4 is disclosed as a water-splitting catalyst ([0447]).
It would have been obvious to one of ordinary skill in the art to coat the bifacial electrode of Domen, Ichinose, and He with cobalt oxide. One would be motivated to do so as Ozin teaches that cobalt oxide is capable of photochemical water splitting, in the alternative to those also taught by He such as TiO2 (He [0061]; Ozin [0166]).
Conclusion
Applicant's amendment necessitated the new grounds 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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/CBF/Examiner, Art Unit 1711
/MICHAEL E BARR/Supervisory Patent Examiner, Art Unit 1711
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