Prosecution Insights
Last updated: April 19, 2026
Application No. 18/137,793

Perovskite Oxygen Carriers and Methods for Making and Using Perovskite Oxygen Carriers

Non-Final OA §103
Filed
Apr 21, 2023
Examiner
PIRO, NICHOLAS ANTHONY
Art Unit
1738
Tech Center
1700 — Chemical & Materials Engineering
Assignee
U.S. Department of Energy
OA Round
1 (Non-Final)
42%
Grant Probability
Moderate
1-2
OA Rounds
3y 4m
To Grant
52%
With Interview

Examiner Intelligence

Grants 42% of resolved cases
42%
Career Allow Rate
8 granted / 19 resolved
-22.9% vs TC avg
Moderate +10% lift
Without
With
+10.0%
Interview Lift
resolved cases with interview
Typical timeline
3y 4m
Avg Prosecution
68 currently pending
Career history
87
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
43.4%
+3.4% vs TC avg
§102
15.0%
-25.0% vs TC avg
§112
23.3%
-16.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 19 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 . 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. Election/Restrictions Applicant’s election of Group 1, claims 1-4, in the reply filed on 25 November 2025 is acknowledged. Because applicant did not distinctly and specifically point out the supposed errors in the restriction requirement, the election has been treated as an election without traverse (MPEP § 818.01(a)). Claims 5-17 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 25 November 2025. Amendments Applicant’s cancellation of claim 2 and amendments to claims 1, 3, and 4 in the reply filed 25 November 2025 are acknowledged and have been considered for this action. Information Disclosure Statement The Information Disclosure Statement filed on 11 October 2023 has been received and considered by the Examiner. 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. 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, 3, and 4 rejected under 35 U.S.C. 103 as being unpatentable over Miura et al. (US 2017/009579 A1) in view of Ikari et al. (US 2023/0197972 A1; effective filing date of 7 August 2020), Motohashi et al. (J. Ceram. Soc. Jap. 2011, 119, 894-897), and Xie et al. (J. Haz. Mater. 2022, 431, 128528; published online 22 February 2022). Regarding claims 1 and 4, Miura teaches a perovskite comprising the formula Sr1-xCaxFeO3-σ, where is 0.12≤x≤0.4 and σ may be zero (abstract). Miura further teaches that this perovskite selectively absorbs oxygen at high pressure and desorbs it at low pressure ([0010]), making it an oxygen carrier, as described in the instant specification ([0005]). Miura does not teach the perovskite oxygen carrier being mesoporous (claim 1) or having a surface area between approximately 2.3 m2/g and approximately 9 m2/g (claim 4). However, Ikari teaches porous composite oxides of the formula ABO3, where A can be Sr and Ca, and B can be Fe, and which therefore include the oxygen carrier compositions taught by Miura ([0031]). Ikari further teaches that such compositions can be used as adsorbents (perovskite-type composite oxides described above have electronic conductivity, and can be utilized, for example, as an adsorbent; [0031]), like those of Miura. Additionally, Ikari teaches that their perovskites are porous ([0076]) and preferably have surface areas of 2.0 m2/g to 10 m2/gm, which overlaps closely with the range recited in claim 4 of from 2.3 m2/g to 9 m2/g. Figure 1 further reveals that the perovskite materials of Ikari have pores in the range 2 to 50 nm, making them mesoporous (instant specification [0072]). Motohashi also discloses perovskite oxygen carriers (p. 894, col. 1, ¶ 2) and additionally teaches that oxygen intake/release rates of the perovskite oxygen carrier are increased by increasing the surface area of the material (oxygen intake/release rates were found to increase significantly as the specific surface area of the sample increases, indicating a key role of the powder surface in the oxygen intake/release processes; p. 894, col. 2, ¶2). Furthermore, Xie also discloses perovskites with gas storage abilities (abstract), and Xie further teaches that perovskites with mesoporous structure and high surface area have improved gas storage ability (LaCoO3-Meso showed a significant advantage for NOx storage, with a NOx storage capacity 2 times higher than the regular sample; abstract). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to prepare the Sr1-xCaxFeO3 perovskite oxygen carrier of Miura according to the method of Ikari such that they are mesoporous and have increased surface areas, and in particular have surface areas of 2.0 m2/g to 10 m2/g, as taught by Ikari. One of ordinary skill in the art would have been motivated to do so because Motohashi teaches that perovskites with increased surface areas have enhanced oxygen intake/release kinetics and because Xie teaches that mesoporous perovskites have significant advantages over non-mesoporous analogs. It is noted that the courts have stated where the claimed ranges “overlap or lie inside the ranges disclosed by the prior art” a prima facie case of obviousness exists (see 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); Titanium Metals Corp. of America v. Banner, 778 F2d 775. 227 USPQ 773 (Fed. Cir. 1985) (see MPEP 2144.05.01). Therefore, the claimed range or surface area merely represents an obvious variant and/or routine optimization of the values of the cited prior art. Regarding claim 3, modified Miura teaches the perovskite oxygen carrier of claim 1, where Ikari teaches the oxygen carrier comprises a network of particles sintered together (the composite oxide powder of the present invention is sintered as a molded body; [0074]) to form a strong porous body (a sintered body is porous and a constant strength is provided [0004]). Ikari further teaches that the precursors to the composite oxides are nanoparticles (the neutralization product of the perovskite-type composite oxide obtained in the present embodiment is amorphous nanoparticles; [0066]) and that the D50 of the composite oxides themselves can be less than 1 μm (Examples 1, 3, 5, and 6; Table 1), meaning they are also comprised of nanoparticles. It is additionally noted that Motohashi also teaches that their perovskite oxygen carriers are formed from networks of nanoparticles (porous agglomerates of fine primary particles…~0.2 μm; p. 895, col. 2, ¶ 3) sintered together (fired at 900 °C; p. 894, col. 2, ¶ 3). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to form the oxygen carrier of modified Miura such that it is formed from a network of nanoparticles sintered together, as taught by Ikari and Motohashi. One of ordinary skill in the art would have been motivated to do so because such a structure is porous and has high surface area with good oxygen uptake and release kinetics, as taught by Motohashi. One of ordinary skill in the art would have been further motivated to do so because sintering as a molded body provides a porous structure and constant strength, as taught by Ikari. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Nicholas A Piro whose telephone number is (571)272-6344. The examiner can normally be reached Mon-Fri, 8:00 am-5:00 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, Sally Merkling can be reached at (571) 272-6297. 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. /NICHOLAS A. PIRO/Assistant Examiner, Art Unit 1738 /PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735
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Prosecution Timeline

Apr 21, 2023
Application Filed
Mar 02, 2026
Non-Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 3 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
42%
Grant Probability
52%
With Interview (+10.0%)
3y 4m
Median Time to Grant
Low
PTA Risk
Based on 19 resolved cases by this examiner. Grant probability derived from career allow rate.

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