Prosecution Insights
Last updated: April 19, 2026
Application No. 18/001,783

CO2 METHANATION USING PLASMA CATALYSIS

Final Rejection §103
Filed
Dec 14, 2022
Examiner
NGUYEN, TAM M
Art Unit
1771
Tech Center
1700 — Chemical & Materials Engineering
Assignee
The University of Liverpool
OA Round
4 (Final)
78%
Grant Probability
Favorable
5-6
OA Rounds
2y 9m
To Grant
88%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
746 granted / 963 resolved
+12.5% vs TC avg
Moderate +11% lift
Without
With
+10.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
68 currently pending
Career history
1031
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
51.2%
+11.2% vs TC avg
§102
16.7%
-23.3% vs TC avg
§112
18.7%
-21.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 963 resolved cases

Office Action

§103
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 . Claim Rejections - 35 USC § 103 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 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. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. 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 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over BISET-PEIRO MARTI et al. : "On the role of ceria in Ni-Al2O3 catalyst for CO2 plasma methanation”, APPLIED CATALYSIS A: GENERAL, vol. 575 , pages 223-229, ISSN: 0926-860X, DOH: 10.1016/). APCATA. 2019.02.028. in view of ANMIN ZHAO et al. : "Ni/Al2O3 catalysts for syngas methanation: Effect of Mn promoter", JOURNAL OF NATURAL GAS CHEMISTRY., vol. 21, no. 2, 1 March 2012 (2072-03-01), pages 170-177, US, GN ISSN: 1003-9953, DO! 10.1016/S1003-9953 (11)60350-2 and Chen et al. (WO 2014/158095 A1). Biset-Peiro discloses an apparatus system for forming methane from carbon dioxide and hydrogen by exposing CO2 to a catalyst in the generated plasma. The system comprises a dielectric barrier discharge device, passageways for CO2 and H2 to pass through and the catalyst comprising 15 wt. % of nickel and cerium on a support of alumina (See pages 223-229). It is reminded that claims 1-6 and 17 are drawn to an apparatus system which includes a manner of operating disclosed system, neither the manner of operating a disclosed device nor material or article worked upon further limit an apparatus claim. Said limitations do not differentiate apparatus claims from prior art. See MPEP §2114 and 2115. Further, process limitations do not have a patentable weight in an apparatus claim. See Exparte Thibault, 164 USPQ 666, 667 (Bd. App. 1969) that states "Expressions relating the apparatus to contents thereof and to an intended operation are of no significance in determining patentability of the apparatus claim. Biset-Peiro does not teach nickel particles having a mean particle diameter in a range from 1 nm to 10nm, and does not teach that the catalyst comprises Mn. Zhao teaches a Ni/Alumina catalyst comprising 1-3 wt.% of Mn. See pages 170-177. Chen discloses a methanation catalyst having a mean particle of about 2 to about 10 nm and Ni is dispersed on the catalyst surface (See abstract; [0008], [0057]). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Biset-Peiro by utilizing Mn as suggested by Zhao because the addition of Mn to Ni/alumina catalyst can increase the catalyst surface area and an average pore volume, but decrease NiO crystallite size, leading to higher activity and stability. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Biset-Peiro by utilizing nickel particles having a mean particle diameter in a range from 2 nm to 8 nm as suggested by Lin because such mean particle diameter provided higher selectivity. Response to Arguments Applicant argues that Biset-Peiró, Zhao, and Chen cannot be combined because plasma catalysis and thermal catalysis involve differing reaction mechanisms, intermediates, and surface chemistry, and therefore a person of ordinary skill in the art (“POSITA”) would not have reasonably looked to Zhao or Chen when modifying the plasma catalytic system of Biset-Peiró. Applicant further asserts that Chen teaches embedded Ni nanoparticles in SiO₂ and therefore cannot be relied upon for surface particle size control in Biset-Peiró’s supported Ni catalyst. Applicant also relies on expert testimony asserting that transfer of insight from thermal catalysis to plasma catalysis is not predictable. The arguments have been fully considered but are not persuasive for the reasons outlined below. 1. Scope of Primary Reference Biset-Peiró discloses a dielectric barrier discharge (DBD) plasma apparatus in which CO₂ and H₂ are converted to methane over a supported Ni–Ce/Al₂O₃ catalyst. As applicant acknowledges, Biset-Peiró teaches: A plasma methanation reactor; A catalyst comprising Ni supported on alumina positioned within a plasma discharge region; and Catalyst deposition on the surface of the alumina support. Accordingly, the method of depositing or supporting Ni on alumina is already taught by the primary reference itself, and the Examiner does not rely on Zhao or Chen to teach catalyst architecture or deposition methodology. 2. Role of Secondary Reference Chen (or alternatively any comparable teaching of nanoparticle Ni sizes in the methanation literature) is cited solely to teach that Ni particles having a mean diameter in the range of about 2–10 nm are known to exhibit improved catalytic activity and stability in methanation reactions. The Examiner does not rely on Chen to teach embedded Ni or a specific synthesis protocol. The claim recites only a mean particle size range, not a required synthesis technique or embedding methodology. Under long-standing Federal Circuit and BPAI precedent, non-claimed manufacturing details have no patentable weight when the claim only recites a structural or compositional result, see MPEP §§ 2114 and 2115. Therefore, the Examiner properly relies on Chen only for the result-effective variable (mean Ni particle size) and not for the manner in which Ni is incorporated into the support. The examiner also has substituted Chen for new Chen (WO 2014/158095 A1), whom teaches that Ni dispersed on the surface of the catalyst as claimed. 3. Result-Effective Variable Doctrine Particle size is a routinely recognized result-effective variable in supported Ni methanation catalysts. Catalyst chemists have long understood that dispersion, crystallite size, and promoter loading are interrelated parameters that can be optimized using routine experimentation. Under MPEP § 2144.05, where the general art recognizes that changing a parameter (such as nanoparticle size) predictably affects catalytic performance, merely optimizing such a parameter is considered obvious unless applicant demonstrates unexpected results. Here, Chen teaches the desirability of preparing Ni catalysts with a mean size of about 2–10 nm to improve methanation performance. A POSITA would understand that nanoparticle size can be controlled by established catalyst preparation techniques (impregnation conditions, calcination temperature, chelating agents, pH, promoter loading, etc.) independent of whether the catalyst operates under thermal or plasma conditions. Accordingly, Chen provides sufficient motivation to optimize the Ni particle size in Biset-Peiró’s supported Ni/Al₂O₃ catalyst, regardless of how the nanoparticle size is achieved or whether Chen employs embedding as an example. 4. Structural Compatibility Between Biset-Peiró and Lin Applicant argues that Chen (now Chen’ WO) is incompatible because it teaches embedding Ni in porous SiO₂. This argument is not persuasive because: The claim does not recite embedding or prohibit embedding; The claim recites only a mean particle diameter range, not a required synthesis method; and When the claimed invention is defined only by size, any technique that suggests the desirability of obtaining nanoparticles of that size provides sufficient motivation, independent of whether the underlying technique is different. Moreover, Biset-Peiró already teaches Ni supported on alumina. Therefore, the Examiner does not rely on Chen (new Chen) to modify how Ni is supported, but only to motivate a POSITA to optimize size. Thus, embedded-versus-surface arguments are not commensurate in scope with the claim, which recites particle size and not the mode of incorporation. 5. Transferability Between Thermal and Plasma Catalysis Applicant argues that plasma catalysis and thermal catalysis are fundamentally distinct and that a POSITA would not look to thermal methanation references to modify a plasma catalyst. This position is not persuasive. While plasma and thermal systems operate via different kinetic pathways, the structural aspects of heterogeneous catalysts (support type, dispersion, crystallite size, promoter effects, surface area) are not tied to reaction mechanism, but to materials engineering principles understood by catalyst chemists independent of operating conditions. A POSITA familiar with supported Ni catalysts would have known, prior to the effective filing date, that: Nickel crystallite size, Promoter loading, Textural stability, Reducibility and dispersion, are materials-design parameters routinely optimized regardless of whether the eventual end use is thermal, plasma, or mixed-mode catalysis. Consequently, relying on Zhao to teach that Mn improves Ni dispersion and relying on Chen to teach that smaller Ni particles improve catalytic activity/selectivity is not a mechanistic transfer, but a materials optimization transfer, well within the routine skill of the art. 6. Motivation to Combine Applicant asserts that a POSITA would not combine Biset-Peiró with Zhao and Chen (new Lin) due to “incompatibility.” However, the combination requires only the adoption of routine catalyst engineering variables: Use of a known promoter (Mn in the claimed range), and Optimization of a known particle size variable (1–10 nm), to improve stability and activity of a supported Ni catalyst. A POSITA would have recognized that the motivating factors (aggregation resistance, dispersion, reducibility, pore structure, improved CO₂ activation) are generic and widely applicable design principles, not tied to a specific mechanism. Thus, there exists a reasoned motivation to optimize size and promoter levels in Biset-Peiró’s supported Ni catalyst, consistent with KSR and MPEP §2141. 7. Unexpected Results Applicant has not presented comparative quantitative data showing that: Mn promotion in a plasma catalyst produces unexpected performance beyond its known stabilizing/dispersion role, or Ni particle size optimization in a plasma catalyst yields a surprising result not predictable from supported Ni catalyst engineering principles. Absent such data, arguments premised only on mechanistic differences are insufficient to overcome a prima facie case of obviousness, especially where the claimed variables are recognized result-effective structural parameters. 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to TAM M NGUYEN whose telephone number is (571)272-1452. The examiner can normally be reached Mon - Frid. 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, Prem C Singh can be reached on 571-273-6381. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /TAM M NGUYEN/Primary Examiner, Art Unit 1771
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Prosecution Timeline

Dec 14, 2022
Application Filed
Nov 02, 2024
Non-Final Rejection — §103
Feb 06, 2025
Response Filed
Feb 12, 2025
Final Rejection — §103
May 16, 2025
Request for Continued Examination
May 19, 2025
Response after Non-Final Action
May 23, 2025
Non-Final Rejection — §103
Aug 11, 2025
Interview Requested
Aug 27, 2025
Examiner Interview Summary
Aug 27, 2025
Applicant Interview (Telephonic)
Oct 26, 2025
Response Filed
Dec 10, 2025
Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
78%
Grant Probability
88%
With Interview (+10.9%)
2y 9m
Median Time to Grant
High
PTA Risk
Based on 963 resolved cases by this examiner. Grant probability derived from career allow rate.

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