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
Claims 5-17 stand withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.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.
Drawings
Color photographs and color drawings are not accepted in utility applications unless a petition filed under 37 CFR 1.84(a)(2) is granted. Any such petition must be accompanied by the appropriate fee set forth in 37 CFR 1.17(h), one set of color drawings or color photographs, as appropriate, if submitted via the USPTO patent electronic filing system or three sets of color drawings or color photographs, as appropriate, if not submitted via the via USPTO patent electronic filing system, and, unless already present, an amendment to include the following language as the first paragraph of the brief description of the drawings section of the specification:
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
Color photographs will be accepted if the conditions for accepting color drawings and black and white photographs have been satisfied. See 37 CFR 1.84(b)(2).
A statement from Applicant that there is no intention to have color drawings will result in acceptance of the drawings, which will be published in black and white; otherwise, the conditions set forth above must be met in order for the color drawings to be accepted.
Amendments
Applicant’s amendments to the claims in the reply filed 8 June 2026 have been entered and considered for this action.
Claim Objections
Claims 20 and 21 are objected to because of the following minor informalities:
Claim 20 uses the notation “°K” but the unit Kelvin should not have a degree symbol;
Claim 21 does not end in a period.
Claim Rejections - 35 USC § 112
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.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 18-21 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 18-21 each recite the limitation “the reduced oxygen carrier”. There is insufficient antecedent basis for this limitation in the claims. Claim 21 further recites the limitation “the contacting step”, which also lacks antecedent basis as there are no steps recited in the composition of claim 1.
Claim 20 is further indefinite because it is unclear precisely what is meant by a “maximum adsorption temperature.” While this limitation appears to refer to the temperature at which the oxygen carrier adsorbs the most oxygen, the specification ([0132]) states that this term actually refers to “the temperature where the reduced oxygen carrier adsorbs oxygen at the fastest rate”. However, none of the compositions presented in Figures 42 or 43 actually absorb oxygen at a fastest rate when the temperature is between 473 K and 673 K. Furthermore, the data on maximum adsorption temperature presented in Table 2 appear to correlate with the temperatures at which the maxima in oxygen adsorption capacity are observed in Figs. 8A-C, and do not appear to correspond temperatures at which a maximum rate oxygen adsorption is achieved. Therefore, there does not appear to be a definition of “maximum adsorption temperature” that is consistent with all portions of the specification and the claim is indefinite.
Claim Rejections - 35 USC § 102
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)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1 and 21 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Dou et al. (ChemSusChem 2020, 13, 385 – 393).
Regarding claim 1, Dou teaches the perovskite oxygen carrier of formula Sr0.8Ca0.2FeO3 (Figure 4, where x=0). Dou further teaches that this material is prepared by a sol-gel method that is substantially similar to the method used to prepare the mesoporous perovskites of the instant claims, as compared in the table below.
Instant Specification ([00138])
Dou (p. 392, col. 1)
Metal sources: strontium nitrate, calcium nitrate tetrahydrate, iron nitrate nonahydrate
Metal sources: strontium nitrate, calcium nitrate tetrahydrate, iron nitrate nonahydrate
Citric acid, 2.5 molar ratio to total metal ions
Citric acid, 2.5 molar ratio relative to total metal ions (50 mmol were used with 20 mmol of metal ions)
Heated to 60 °C and stirred to dissolve
Metals dissolved and then citric acid added and stirred for 30 min to form a solution
Ethylene glycol added in a 3.75:1 molar ratio relative to metals
Ethylene glycol is added in a 3.75 molar ratio relative to metals (75 mmol for 20 mmol metal)
Heated to 120 °C to dehydrate the material, placed in an oven at 120 °C for overnight drying
Resulting solution was heated at 80 °C for 3 h to form orange-colored gel, which was then dried in an oven at 120°C for 16 h
Ground to a rough powder and then heated in air to a desired synthesis temperature (e.g., 1000 °C) at 5 °C/min and then held for 8 hours.
Calcined in air for 8 h at 1000 °C
Therefore, as the method of Dou is substantially similar to that of the instant invention, it is held that the materials of Dou prepared by said method will also be mesoporous and comprised of nanoparticles sintered together.
Once a reference teaching product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning to show inherency, the burden of production shifts to the applicant. "[T]he PTO can require an applicant to prove that the prior art products do not necessarily or inherently possess the characteristics of [their] claimed product. Whether the rejection is based on inherency’ under 35 U.S.C. 102, on prima facie obviousness’ under 35 U.S.C. 103, jointly or alternatively, the burden of proof is the same, and its fairness is evidenced by the PTO’s inability to manufacture products or to obtain and compare prior art products." In re Best, 562 F.2d 1252, 1255, 195 USPQ 4380, 483-34 (CCPA 1977)), see MPEP 2112.
Regarding claim 21, Dou teaches the perovskite oxygen carrier of claim 1, and further teaches that the carrier is oxidized by 0.2 wt% in 1 minute when contacted with 20% O2 (Fig. 6d), which is at a rate of 0.2 wt%/min.
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.
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Dou et al. (ChemSusChem 2020, 13, 385 – 393), as applied to claim 1 above, and further in view of Motohashi et al. (J. Ceram. Soc. Jap. 2011, 119, 894-897).
Regarding claim 4, Dou teaches the perovskite oxygen carrier of formula Sr0.8Ca0.2FeO3 (Figure 4, where x=0). Dou further teaches that this material is prepared by a sol-gel method that is substantially similar to the method used to prepare the mesoporous perovskites of the instant claims, as compared in the table above. Therefore, it was concluded that the material of Dou meets the limitations of mesoporous and comprised of nanoparticles sintered together. Dou does not teach the surface area of their material, though evidence from the instant specification suggests that because of the sintering temperature of 1000 °C it would have been lower than the range of approximately 2.3 m2/g to 9 m2/g recited in instant claim 4.
However, 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). Motohashi further teaches that one way to increase surface area and uptake/release rates is to use a lower sintering temperature (compare EDTA-900 and EDTA-1000 in Table 1 and Fig. 4). Motohashi further explains that lowering of the synthesis temperature effectively suppresses the grain growth, and that the surface areas are accordingly enhanced as the synthesis temperature is lowered (p. 895, 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 optimize by routine experimentation the sintering temperature used in the method of Duo, thereby increasing the surface area of the perovskite oxygen carrier, including into the claimed range of 2.3 m2/g to 9 m2/g. One of ordinary skill in the art would have been motivated to do so in order to increase the adsorption/desorption rates of the oxygen carrier, as taught by Motohashi.
Claims 18-20 are rejected under 35 U.S.C. 103 as being unpatentable over Dou et al. (ChemSusChem 2020, 13, 385 – 393), as applied to claim 1 above, and further in view of Motohashi et al. (J. Ceram. Soc. Jap. 2011, 119, 894-897) and Miura et al. (Ind. Eng. Chem. Res. 2016, 55, 3091−3096; hereinafter “Miura ’16”).
Regarding claims 18-20, Dou teaches the perovskite oxygen carrier of formula Sr0.8Ca0.2FeO3 (Figure 4, where x=0). Dou further teaches that this material is prepared by a sol-gel method that is substantially similar to the method used to prepare the mesoporous perovskites of the instant claims, as compared in the table above. Therefore, it was concluded that the material of Dou meets the limitations of mesoporous and comprised of nanoparticles sintered together. Dou does not teach the oxygen carrier being adapted to absorb between approximately 2.00 wt% and approximately 3.00 wt% oxygen, or at least 2.00 wt% oxygen, as required by instant claims 18 and 19. Dou also does not teach a maximum adsorption temperature as required by claim 20.
However, 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). Motohashi further teaches that one way to increase surface area and uptake/release rates is to use a lower sintering temperature (compare EDTA-900 and EDTA-1000 in Table 1 and Fig. 4). Motohashi further explains that lowering of the synthesis temperature effectively suppresses the grain growth, and that the surface areas are accordingly enhanced as the synthesis temperature is lowered (p. 895, col. 2, ¶ 3).
Additionally, Miura ’16 teaches that the Sr1-xCaxFeO3-δ materials with x=0, x=0.2, and x=0.24 adsorb approximately 2.2 wt%, 1.95 wt%, and 1.65 wt% oxygen (Figure 3a), while the x=0.1 material absorbs 2.1 wt% oxygen (from Figure 4 by applying Eq. 2). Miura ’16 further teaches that the x=0.24 material is best for pressure swings between air and 5 vol% O2 environments, but that the performance in air-N2 depends differently on the value of x in the materials, with lower values of x performing better in air-N2 swings (Figure 4). In other words, Miura ’16 teaches that depending upon which conditions the carrier is to be deployed in, different compositions of formula Sr1-xCaxFeO3-δ may be optimal.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to optimize the method of Duo by routine experimentation by varying the sintering temperature and the amount of calcium in the oxygen carrier, as taught by Motohashi and Miura ’16, respectively. One of ordinary skill in the art would have been motivated to do so in order to increase the adsorption/desorption rates of the oxygen carrier, as taught by Motohashi, and to increase the oxygen carrier capacity (amount of oxygen absorbed and released), as taught by Miura ’16.
Through such optimization by routine experimentation one of ordinary skill in the art would arrive at perovskite oxygen carriers prepared by methods that are substantially similar to those of the instant invention in terms of preparation steps, composition and sintering temperature. Accordingly, such products would be expected to have substantially similar properties, including an ability to adsorb oxygen from a reduced state at a level of between approximately 2.00 wt% and 3.00 wt% and a maximum absorption temperature between approximately 473 K and 673 K, as required by the instant claims. For example, the modifications suggested to the method of Dou by Motohashi would lead one of ordinary skill in the art to a sintering temperatures of 900 °C, while the teachings of Miura ’16 would lead one to a composition of Sr0.76Ca0.24FeO3. The perovskite oxygen carrier prepared such would be expected to have properties substantially similar to the carrier of Sr0.75Ca0.25FeO3 with Ts=900 °C of the instant invention, whose properties are revealed in Fig. 42 and Table 2, and which meets all the limitations of the instant claims.
It is again noted that once a reference teaching product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning to show inherency, the burden of production shifts to the applicant. See MPEP 2112.01.
Response to Arguments
Applicant's arguments filed 8 June 2026 have been fully considered but are moot because the new grounds of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the arguments.
Conclusion
This Office action presents new grounds of rejection that were not necessitated by Applicant’s amendments to the claims. As such, this action is NOT FINAL.
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.
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/NICHOLAS A. PIRO/Assistant Examiner, Art Unit 1738
/PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735
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