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 02/20/2026.
Status of Rejections
The rejection of claim(s) 3-5 and 18-20 under 35 USC 112(b) is/are withdrawn in view of applicant’s amendment.
All other previous rejections are withdrawn in view of applicant’s amendments.
New grounds of rejection are necessitated by applicant’s amendments.
Claims 3-5 and 18-25 are pending and under consideration for this Office Action.
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 3-5 and 19-23 are rejected under 35 U.S.C. 103 as being unpatentable over Lee et al. (“New strategies for economically feasible CO2 electroreduction using a porous membrane in zero-gap configuration”, J. Mater. Chem. A, Jul 2021) in view of Yamada et al. (U.S. 2018/0073154), and further in view of Sargent et al. (WO 2019185622 A1); claim 4 evidenced by Yoon et al. (“Supporting Information—Impact of Side Chains in 1-n-Alkylimidazolium Ionomers on Cu-Catalyzed Electrochemical CO2 Reduction”, Adv. Sci., 2024)”, and claim 21 evidenced by Evantic (“Chemical Compatibility Chart, Evantic, 2025).
Regarding claim 3, Lee teaches a gas diffusion electrode suitable for carbon dioxide electrolysis (see e.g. Figs. 1a-1b, cathode for CO2RR with gas diffusion layer through which gaseous CO2 passes), said gas diffusion electrode having a gas diffusion membrane (see e.g. Fig. 1a, gas diffusion layer comprising carbon paper; Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines 1-2), the gas diffusion electrode further comprising an ink deposited on the gas diffusion membrane (see e.g. Fig. 1a, catalyst layer formed by ink sprayed on the carbon paper GDL; Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines 1-2), wherein the ink comprises an ion-conducting polymer (see e.g. Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines 3-4, catalyst ink comprising Nafion ionomer), said gas diffusion electrode being characterized in that the ink further comprises a catalyst comprising copper nanoparticles (Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines 3-8, catalyst ink comprising Cu nanoparticle powder).
Lee does not teach the copper nanoparticles being functionalized with one or more pyridine-containing ligands, wherein the one or more pyridine-containing ligands are selected from the group consisting of 4-pyridylethylmercaptan, 4-mercaptopyridine, 2,6-dimethyl-4-mercaptopyridine, 2-mercaptopyridine and any mixture thereof.
Yamada teaches a reduction catalyst for electrochemical reduction of a compound such as CO2 (see e.g. Paragraph 0022-0023) comprising catalyst nanoparticles of a metal such as Cu (see e.g. Figs. 1-2, conductive layer 102 constituted by nano-fine particles or metal fine particles 107; Paragraph 0031, lines 7-11, Paragraphs 0033-0034 and 0091-0092) to which organic modifying groups, i.e. ligands, containing pyridine, such as 4-mercaptopyridine, are attached (see e.g. Figs. 1-2, organic modifying groups 103 containing pyridine/bipyridine; Paragraphs 0040-0041, 0070 and 0074), the inclusion of these organic modifying groups improving reaction efficiency by favorably supplying electrons required for CO2 reduction, inhibiting hydrogen generation and thereby suppressing bubble generation (see e.g. Paragraph 0075 and Paragraph 0076, lines 5-13).
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 copper nanoparticles of Lee to comprise pyridine-containing organic modifying groups, such as 4-mercaptopyridine, attached to them as taught by Yamada to improve reaction efficiency by favorably supplying electrons required for CO2 reduction, inhibiting hydrogen generation and thereby suppressing bubble generation.
Lee as modified by Yamada above does not explicitly teach the one or more pyridine-containing ligands being present in a surface concentration ranging from 5 nmol cm-2 to 40 nmol cm-2 as determined by reductive desorption and UV-visible spectroscopy as set out in the description, and the ink having a weight ratio of the copper nanoparticles functionalized with one or more pyridine-containing ligands over the ion-conducting polymer ranging from 12 to 40.
Yamada does however teach the density, i.e. concentration, of the ligands influencing the yielded products, with examples of less than 1x1011 atoms/cm2, equal to less than 0.000166 nmol/cm2, yielding mainly formic acid, formaldehyde and methanol, and 1x1013 to 1x1015 atoms/cm2, equal to 0.0166 to 1.66 nmol/cm2, yielding mainly acetic acid acetaldehyde and ethanol (see e.g. Yamada Paragraph 0174, lines 1-18), and wherein the relationships between molecular density and products may be discovered by experimental studies (see e.g. Yamada Paragraph 0174, lines 18-21). Page 24, line 28-Page 25, line 2, of the instant specification similarly describe the amount of the pyridine-containing ligand on the electrode affecting selectivity towards formate production. Lee teaches formate being an exemplary desired product of the CO2 reduction reaction at the gas diffusion electrode (see e.g. Lee Page 16169, Col. 1, lines 1-4). Lee additionally teaches the ink having a weight ratio of the copper nanoparticles over the ion-conducting polymer of 20 (see e.g. Lee Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines, 3-8, Nafion provided at 5 wt% of the commercial Cu nanopowder, resulting in a Cu:Nafion ratio of 20), and the copper nanoparticles being present in a loading of 0.5 mg/cm2 (see e.g. Lee Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines 6-9, Cu metal loading), which, in combination with the 4-mercaptopyridine of Yamada in the claimed concentration of 5 nmol cm-2 to 40 nmol cm-2-, i.e. 0.56 to 4.45 µg/cm2 of 4-mercaptopyridine, would result in a functionalized copper to ion-conducting polymer weight ratio of 20.02 to 20.18.
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 surface concentration of the pyridine-containing ligands in the electrode of modified Lee to within the claimed range, resulting in a functionalized copper to ion-conducting polymer weight ratio of 20.02 to 20.18, through routine experimentation to influence selectivity towards a desired product such as formate. MPEP § 2144.05 II states “Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[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."” The surface concentration of the pyridine-containing ligand is a results-effective variable influencing the yielded products as taught by Yamada above.
Modified Lee does not teach the gas diffusion membrane being a hydrophobic porous support having a pore size between 300 nm and 580 nm, instead only teaching it comprising carbon paper (see e.g. Lee Fig. 1a, gas diffusion layer comprising carbon paper; Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines 1-2).
Sargent teaches a cathode for CO-2 reduction (see e.g. Page 5, lines 19-23) comprising a hydrophobic gas diffusion layer provided adjacent a catalyst layer (see e.g. Page 1, line 25), wherein the hydrophobic gas diffusion layer may preferably have pores with a diameter ranging from 50 nm to 500 nm (see e.g. Page 2, line 30-Page 3, line 3, and Page 6, lines 22-24), overlapping the claimed range of the present invention, this hydrophobic gas diffusion layer being more stable than a conventional carbon gas diffusion layer that can lose its hydrophobicity and cause electrode degradation under continuous CO2RR operation (see e.g. Page 9, line 29-Page 10, line 5, and Page 10, lines 14-15 and 23-25).
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 gas diffusion membrane of modified Lee to instead comprise the hydrophobic gas diffusion layer with pores having a diameter of 50 nm to 500 nm taught by Sargent as a more stable gas diffusion layer than the conventional carbon paper gas diffusion layer that can lose its hydrophobicity and cause electrode degradation under continuous CO2RR operation. 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)(B) states that “simple substitution of one known element for another to obtain predictable results” may be obvious.
Regarding claim 4, modified Lee teaches the copper nanoparticles comprising Cu(200) and Cu(111) facets (see e.g. Lee Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines 3-7, commercial Cu nanoparticle powder from Sigma Aldrich; evidenced by Yoon to comprise exposed 200 and 111 facets, see e.g. Yoon Page S2, lines 4-5, and Fig. S6).
Regarding claim 5, Lee as modified by Yamada above does not explicitly teach the copper nanoparticles having an average diameter ranging from 5 nm to 200 nm as measured by transition electron microscopy. Yamada further teaches that metal fine particles used as a reduction catalyst preferably having an average size of 1 nm to 150 nm, overlapping the claimed range of the present invention (see MPEP § 2144.05 I as cited above), in order to provide high catalytic activity and efficiency while not being too difficult to produce (see e.g. Yamada Paragraphs 0033-0034).
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 copper nanoparticles of modified Lee to have an average diameter of 1 nm to 150 nm as taught by Yamada to provide high catalytic activity and efficiency while not being too difficult to produce.
Regarding claims 19-20, Lee as modified by Yamada teaches the ink having a weight ratio of the copper nanoparticles functionalized with one or more pyridine-containing ligands over the ion-conducting polymer ranging from 20.02 to 20.18 (see e.g. Lee Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines, 3-9, Nafion provided at 5 wt% of the commercial Cu nanopowder, resulting in a Cu:Nafion ratio of 20, and Cu present in loading of 0.5 mg/cm2; the weight ratio with the ligand such as 4-mercaptopyridine of Yamada in the claimed range of 5 to 40 nmol/cm2, equal to 0.56 to 4.45 µg/cm2, would therefore be slightly greater than 20 at about 20.02 to 20.18).
Regarding claim 21, Lee as modified by Sargent teaches the gas diffusion membrane being not soluble in KOH (see e.g. Sargent Page 6, lines 18-21, hydrophobic gas diffusion layer preferably composed of PTFE; which is evidenced by Evantic to be stable, i.e. not soluble in KOH, see e.g. Evantic Chemical Compatibility Chart, PTFE with potassium hydroxide).
Regarding claim 22, Lee as modified by Sargent teaches the gas diffusion membrane being polytetrafluoroethylene (see e.g. Sargent Page 6, lines 18-21).
Regarding claim 23, Lee as modified by Sargent teaches the gas diffusion membrane having a thickness of 50 to 400 µm, or preferably 100 to 300 µm (see e.g. Sargent Page 6, liens 25-27), encompassing or overlapping the claimed range of the present invention (see MPEP § 2144.05 I as cited above).
Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over Lee, Yamada and Sargent, as applied to claim 3 above, and further in view of Fang et al. (“Electrochemical Reduction of CO2 at Functionalized Au Electrodes”, J. Am. Chem. Soc., 2017).
Regarding claim 18, modified Lee teaches all the elements of the electrode of claim 3 as stated above. Modified Lee does not explicitly teach the one or more pyridine-containing ligands being selected from the group consisting of 4-pyridylethylmercaptan, 2,6-dimethyl-4-mercaptopyridine, 2-mercaptopyridine and any mixture thereof. Yamada does however teach that the pyridine-containing ligand may preferably be of the formula B shown below, where R may be hydrogen or a heterohydrocarbon group such as a mercaptoalkyl group, which includes examples such as 3-mercaptomethylpyridine and 4-mercaptomethylpyridine (see e.g. Yamada Paragraphs 0042-0045, 0070-0072 and 0073), and the ligand contributing to electron supply (see e.g. Yamada Paragraph 0076, lines 5-13).
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Fang teaches an electrode for electrochemical reduction of CO2 (see e.g. Abstract) functionalized with a pyridine containing ligand such as 4-pyridylethylmercaptan shown below (see e.g. Abstract, Table 2 and Scheme 1), which fits formula B with one R as hydrogen and the other R as a mercaptoethyl, i.e. mercaptoalkyl, group.
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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 pyridine-containing ligand of modified Lee to comprise 4-pyridylethylmercaptan as taught by Fang as a suitable pyridine-containing functionalizing ligand for use with an electrode for electrochemical reduction of CO2 that satisfies the formula B preferred by Yamada. 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 24 is rejected under 35 U.S.C. 103 as being unpatentable over Lee, Yamada and Sargent, as applied to claim 3 above, and further in view of Li et al. (“The role of electrode wettability in electrochemical reduction of carbon dioxide”, J. Mater. Chem. A, July 2021).
Regarding claim 24, modified Lee teaches all the elements of the electrode of claim 3 as stated above. Modified Lee does not teach the ion-conducting polymer being or comprising tetrafluoroethylene-perfluoro(3-hydrophobioxa-4-pentesulfonic acid) copolymer, exemplified as Aquivion® on Page 13, lines 19-21 of the instant specification, instead only teaching it comprising Nafion (see e.g. Lee Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines 3-4, catalyst ink comprising Nafion ionomer), which is tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer as described on Page 13, lines 17-19 of the instant specification.
Li relates to electrochemical reduction of carbon dioxide (see e.g. Abstract) and exemplifies various catalysts layers for CO-2RR that have been formed with additives such as Nafion or Aquivion ionomers (see e.g. Table 3).
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 ion-conducting polymer of modified Lee to instead comprise Aquivion, i.e. tetrafluoroethylene-perfluoro(3-hydrophobioxa-4-pentesulfonic acid) copolymer, as taught by Li as an alternate suitable ionomer additive to Nafion that can be used in catalyst layers for CO2RR. MPEP § 2143(I)(B) states that “simple substitution of one known element for another to obtain predictable results” may be obvious. Further, MPEP § 2144.07 states “The selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945)”.
Claim 25 is rejected under 35 U.S.C. 103 as being unpatentable over Lee, Yamada and Sargent, as applied to claim 3 above, and further in view of Kang et al. (U.S. 2020/0385878).
Regarding claim 25, modified Lee teaches all the elements of the electrode of claim 3 as stated above. Modified Lee does not teach the gas diffusion electrode having a mass loading of the ink onto the gas diffusion membrane from 1.50 mg/cm2 to 2.00 mg/cm2, instead teaching a copper mass loading of 0.50 mg/cm2 and resultant ink mass loading of 0.526 to 0.529 mg/cm2 (see e.g. Lee Page 16176, Col. 1, under “Electrode preparation for CO2 reduction”, lines 3-9, 0.5 mg.cm2 Cu with Cu:Nafion ratio of 20:1 and 4-mercaptopyridine of Yamada in the claimed concentration of 5 nmol cm-2 to 40 nmol cm-2-, i.e. 0.56 to 4.45 µg/cm2 of 4-mercaptopyridine).
Kang teaches a copper nanocatalyst (see e.g. Abstract) which may be used foe conversion of carbon dioxide (see e.g. Paragraph 0019), wherein the copper nanocatalyst may be provided on a substrate at a loading amount of 0.1--3.0 mg/cm2 (see e.g. Paragraph 0007), encompassing the exemplary 0.5 mg/cm2 Cu loading of Lee, which, in combination with modified Lee, would result in a mass loading of ink of 0.106 to 3.15 mg/cm2, encompassing 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 gas diffusion electrode of modified Lee to have a copper mass loading of 0.1-3.0 mg/cm2, resulting in an ink mass loading of 0.106 to 3.15 mg/cm2, as taught by Kang as a suitable loading range for a copper nanocatalyst on a substrate for conversion of carbon dioxide. 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.
Response to Arguments
Applicant’s arguments, see page 1 of “Remarks”, filed 02/20/2026, with respect to the rejection(s) of claim(s) 3 under 35 USC 103 over Lee in view of Yamada, particularly regarding the gas diffusion membrane being a hydrophobic porous support with a pores size of 300 to 580 nm, 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 Lee, Yamada and Sargent.
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