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 non-final office action in response to applicant's arguments and remarks filed on 04/27/2026.
Status of Rejections
The rejection of claim 18 is obviated by the Applicant’s cancellation.
The rejection of claim 21 under 35 USC 112(b) is withdrawn in view of the Applicant’s amendment.
All other rejections are withdrawn in view of the Applicant’s arguments.
New grounds of rejection are presented.
Claims 1-10, 19-21, and 32-37 are pending and under consideration for this Office Action.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claim(s) 1-5 and 32-36 is/are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Xu et al (“High selectivity of sulfur-doped SnO2 in NO2 detection at lower operating temperatures”, Nanoscale, 2018, 10, 20761-20771).
Claim 1: Xu discloses a product comprising tin oxide doped with sulfur (see e.g. abstract), wherein the sulfur concentration is between 0.02-1.8 at% (see e.g. page 20765, connecting paragraph of col 1 and col 2).
The limitation of the preamble claiming the invention is a catalyst is an intended use. MPEP § 2111.02 II states that ‘If the body of a claim fully and intrinsically sets forth all of the limitations of the claimed invention, and the preamble merely states, for example, the purpose or intended use of the invention, rather than any distinct definition of any of the claimed invention’s limitations, then the preamble is not considered a limitation and is of no significance to claim construction. Shoes by Firebug LLC v. Stride Rite Children’s Grp., LLC, 962 F.3d 1362, 2020 USPQ2d 10701 (Fed. Cir. 2020)’.
Claim 2: Xu discloses that the catalyst does not contain a precious metal (it is just sulfur and tin oxide, see e.g. abstract).
Claim 3: Xu discloses that the catalyst comprises at least 95% of the sum of the elements Sn, O, and S (it is a zinc oxide doped with sulfur, see
e.g. abstract).
Claim 4: Xu discloses a sulfur content of 0.02-1.8 at% (see e.g. page 20765, connecting paragraph of col 1 and col 2).
Claim 5: Xu discloses that sulfur atoms are dispersed in a surface of the SnO2 (see e.g. abstract).
Claim 32: Xu discloses a product comprising tin oxide doped with sulfur (see e.g. abstract), wherein the sulfur concentration is between 0.02-1.8 at% (see e.g. page 20765, connecting paragraph of col 1 and col 2).
The limitation of the preamble claiming the invention is a catalyst is an intended use. MPEP § 2111.02 II states that ‘If the body of a claim fully and intrinsically sets forth all of the limitations of the claimed invention, and the preamble merely states, for example, the purpose or intended use of the invention, rather than any distinct definition of any of the claimed invention’s limitations, then the preamble is not considered a limitation and is of no significance to claim construction. Shoes by Firebug LLC v. Stride Rite Children’s Grp., LLC, 962 F.3d 1362, 2020 USPQ2d 10701 (Fed. Cir. 2020)’.
Claim 33: Xu discloses a sulfur content of 0.02-1.8 at% (see e.g. page 20765, connecting paragraph of col 1 and col 2).
Claim 34: Xu discloses a sulfur content of 0.02-1.8 at% (see e.g. page 20765, connecting paragraph of col 1 and col 2).
Claim 35: Xu discloses a sulfur content of 0.02-1.8 at% (see e.g. page 20765, connecting paragraph of col 1 and col 2).
Claim 36: Xu discloses that the tin oxide is in the form of SnO2 (see e.g. abstract) nanoparticles (see e.g. page 20764, col 1: “consist of numerous nanoparticles”) doped with sulfur (see e.g. abstract).
Claim(s) 32-34 is/are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Babu et al (“Fabrication of thin film using insoluble sulphur doped on tin oxide through electro spray technique”, Materials Today: Proceedings, 2021, pages 1960-1966, Volume 47, Part 9).
Claim 32: Babu discloses a catalyst comprising tin oxide doped with sulfur (see e.g. abstract; page 1962, col 2, paragraph starting with “Fig. 4c”), wherein the sulfur concentration is between 1 to 3 at% (see e.g. page 1961, col 1, paragraph starting with “A suitable”).
Claim 33: Babu discloses that the sulfur concentration is between 1 to 3 at% (see e.g. page 1961, col 1, paragraph starting with “A suitable”).
Claim 34: Babu discloses that the sulfur concentration is between 1 to 3 at% (see e.g. page 1961, col 1, paragraph starting with “A suitable”).
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.
Claim(s) 1-5, 35, and 36 is/are rejected under 35 U.S.C. 103 as being unpatentable over Babu.
Claim 1: Babu discloses a catalyst comprising tin oxide doped with sulfur (see e.g. abstract; page 1962, col 2, paragraph starting with “Fig. 4c”), wherein the sulfur concentration is between 0 to 3 at%, with specific examples including 1 and 2 at% (see e.g. page 1961, col 1, paragraph starting with “A suitable”), overlapping with the claimed range of 0.1 to 2 at%. 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. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)’.
Claim 2: Babu discloses that the catalyst does not contain a precious metal (it is just sulfur and tin oxide, see e.g. abstract).
Claim 3: Babu discloses that the catalyst comprises at least 95% of the sum of the elements Sn, O, and S (it is a zinc oxide doped with sulfur, see
e.g. abstract).
Claim 4: Babu discloses a catalyst comprising tin oxide doped with sulfur (see e.g. abstract), wherein the sulfur concentration is between 0 to 3 at%, with specific examples including 1 and 2 at% (see e.g. page 1961, col 1, paragraph starting with “A suitable”), overlapping with the claimed range of 1.2 to 1.6 at%. 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. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)’.
Claim 5: Babu discloses that sulfur atoms are dispersed in a surface of the SnO2.(see e.g. page 1962, col 2, paragraph starting with “Optical”; page 1965, col 1, paragraph starting with “Fig 8b”).
Claim 35: Babu discloses that the sulfur concentration is between 1 to 3 at% (see e.g. page 1961, col 1, paragraph starting with “A suitable”), with specific examples including 1 and 2 at% (see e.g. page 1961, col 1, paragraph starting with “A suitable”).
Claim 36: Babu discloses that the tin oxide is in the form of SnO2 (see e.g. page 1961, col 2, paragraph starting with “The structural) nanoparticles (see e.g. page 1963, Fig 5) doped with sulfur (see e.g. abstract).
Claim(s) 6-10, 19-21, and 37 is/are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al (“Sn nanoparticles deposited onto a gas diffusion layer via impregnation-electroreduction for enhanced CO2 electroreduction to formate”, Electrochimica Acta, Volume 369, 10 February 2021, 137662) in view of Sen et al (“Electroreduction of carbon dioxide to formate at high current densities using tin and tin oxide gas diffusion electrodes”, Journal of Applied Electrochemistry, 2019, 49:917–928) and Babu.
Claim 6: Wang discloses a catalyst ink (see e.g. page 2, col 2, paragraph starting with “Preparation of IE-Sn”) comprising;
a liquid carrier (water, see e.g. page 2, col 2, paragraph starting with “Preparation of IE-Sn”);
conductive particles (carbon, see e.g. see e.g. page 2, col 2, paragraph starting with “Preparation of IE-Sn”);
optionally an ionomer (Nafion, see e.g. page 2, col 2, paragraph starting with “Preparation of IE-Sn”), and
a tin-based catalyst (see e.g. page 2, col 2, paragraph starting with “Preparation of IE-Sn” and abstract).
Wang does not explicitly teach that the catalyst is the catalyst of claim 1. However, Wang discloses that the catalyst is for the electroreduction of carbon dioxide to formate (see e.g. abstract).
Sen teaches a tin oxide catalyst for the electroreduction of carbon dioxide to formate (see e.g. abstract), making it analogous art to the instant invention and Wang (see MPEP § 2141.01(a) I). Sen compares the performance of tin oxide to tin catalysts for the reaction. “We find that, over the course of a 1-h electrolysis, both electrodes retain high selectivity (> 70%) for the desired product at current densities in excess of 200 mA cm−2 at catalyst loadings of 0.35 mg cm−2, and that the SnO2 GDEs outperform the Sn GDEs due to enhanced reaction kinetics” (see e.g. page 926, col 1, “Conclusions”). Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention to modify the ink of Wang to use tin oxide instead of tin because tin oxide has enhanced reaction kinetics.
Additionally, Babu teaches a sulfur doped tin oxide based catalyst (see e.g. abstract; page 1962, col 2, paragraph starting with “Fig. 4c”) making it analogous art to the instant invention and Wang (see MPEP § 2141.01(a) I). The catalyst of Babu comprises tin oxide doped with sulfur (see e.g. abstract), wherein the sulfur concentration is between 0 to 3 at%, with specific examples including 1 and 2 at% (see e.g. page 1961, col 1, paragraph starting with “A suitable”). The introduction of sulfur into tin oxide increases catalytic activity (see e.g. page 1962, col 2, paragraph starting with “Fig. 4c”). Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention to modify the ink of Wang in view of Sen to dope the catalyst with sulfur at the concentrations taught in Babu to improve the catalytic activity.
Claim 7: Wang in view of Sen and Babu discloses that the conductive particles comprise conductive carbon (see e.g. Wang - see e.g. see e.g. page 2, col 2, paragraph starting with “Preparation of IE-Sn”).
Claim 8: Wang in view of Sen and Babu discloses an alkaline ionomer binder (Nafion, see e.g. Wang - page 2, col 2, paragraph starting with “Preparation of IE-Sn”).
Claim 9: Wang in view of Sen and Babu discloses that the liquid carrier comprises deionized water (see e.g. Wang - page 2, col 2, paragraph starting with “Preparation of IE-Sn”).
Claim 10: Wang in view of Sen and Babu discloses that the ink comprises ethanol (see e.g. Wang - page 2, col 2, paragraph starting with “Preparation of IE-Sn”).
Claim 19: Wang discloses a tin catalyst-containing gas diffusion electrode (see e.g. abstract) comprising a tin catalyst (see e.g. abstract) dispersed onto substrate (see e.g. page 2, col 2, paragraph starting with “Preparation of GDL”).
Wang teaches that carbon paper is a known and suitable substrate for these types of electrodes (see e.g. page 2, col 1, paragraph starting “The CL”: “The CL is typically comprised of a mixture of a binder (e.g., Nafion), carbon materials (e.g., carbon black), and Sn nanoparticles deposited onto a GDL (e.g., carbon film including of carbon black, polytetrafluoroethylene, and metal mesh; or carbon paper)”). Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention to select carbon paper as the substrate because KSR rationale E states that is obvious to choose “from a finite number of identified, predictable solutions, with a reasonable expectation of success” and 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)”.
Wang does not explicitly teach that the catalyst is the catalyst of claim 1. However, Wang discloses that the catalyst is for the electroreduction of carbon dioxide to formate (see e.g. abstract).
Sen teaches a tin oxide catalyst for the electroreduction of carbon dioxide to formate (see e.g. abstract), making it analogous art to the instant invention and Wang (see MPEP § 2141.01(a) I). Sen compares the performance of tin oxide to tin catalysts for the reaction. “We find that, over the course of a 1-h electrolysis, both electrodes retain high selectivity (> 70%) for the desired product at current densities in excess of 200 mA cm−2 at catalyst loadings of 0.35 mg cm−2, and that the SnO2 GDEs outperform the Sn GDEs due to enhanced reaction kinetics” (see e.g. page 926, col 1, “Conclusions”). Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention to modify the ink of Wang to use tin oxide instead of tin because tin oxide has enhanced reaction kinetics.
Additionally, Babu teaches a sulfur doped tin oxide based catalyst (see e.g. abstract; page 1962, col 2, paragraph starting with “Fig. 4c”) making it analogous art to the instant invention and Wang (see MPEP § 2141.01(a) I). The catalyst of Babu comprises tin oxide doped with sulfur (see e.g. abstract), wherein the sulfur concentration is between 0 to 3 at%, with specific examples including 1 and 2 at% (see e.g. page 1961, col 1, paragraph starting with “A suitable”). The introduction of sulfur into tin oxide increases catalytic activity (see e.g. page 1962, col 2, paragraph starting with “Fig. 4c”). Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention to modify the ink of Wang in view of Sen to dope the catalyst with sulfur at the concentrations taught in Babu to improve the catalytic activity.
Claim 20: Wang in view of Sen and Babu discloses that the electrode comprises an ionomer (Nafion, see e.g. Wang - page 2, col 2, paragraph starting with “Preparation of IE-Sn”).
Claim 21: The limitation claiming “The S-SnO2 catalyst-containing gas diffusion electrode of claim 19 characterizable by Faradaic efficiency of at least 60%” is describing a property of the electrode. Wang in view of Sen and Babu teaches all of the positively recited structure for claim 19. Therefore, the properties of the two electrodes would be same. Alternatively, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention that the two electrodes would have substantially similar properties because the electrodes are substantially similar.
The limitation claiming “wherein the Faradaic efficiency is measurable by electrochemically reacting carbon dioxide and water in the presence of the catalyst at a current density of 200 mA cm-2 in a 6 cm2 membrane electrode assembly electrolyzer cell and measuring the fraction of total charge consumed that produces formic acid or formate” describes how the efficiency is measured and does not structurally limit the electrode.
Claim 37: The limitation claiming “The S-SnO2 catalyst-containing gas diffusion electrode of claim 19 characterizable by Faradaic efficiency between 60% and 85%” is describing a property of the electrode. Wang in view of Sen and Babu teaches all of the positively recited structure for claim 19. Therefore, the properties of the two electrodes would be same. Alternatively, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant invention that the two electrodes would have substantially similar properties because the electrodes are substantially similar.
The limitation claiming “wherein the Faradaic efficiency is measurable by electrochemically reacting carbon dioxide and water in the presence of the catalyst at a current density of 200 mA cm-2 in a 6 cm2 membrane electrode assembly electrolyzer cell and measuring the fraction of total charge consumed that produces formic acid or formate” describes how the efficiency is measured and does not structurally limit the electrode.
Response to Arguments
Applicant’s arguments filed 04/27/2026 with respect to the rejection(s) of the claim(s) under 35 USC 112(b) over Zheng 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 Xu and Babu.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXANDER W KEELING whose telephone number is (571)272-9961. The examiner can normally be reached 7:30 AM - 4:00 PM. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Luan Van can be reached at 571-272-8521. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/ALEXANDER W KEELING/Primary Examiner, Art Unit 1795
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