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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 1/23/2026 has been entered.
Response to Arguments
With respect to the rejection of Claims 1 and 8-11 under 35 U.S.C. 102(a)(1) as being anticipated by Kuhn et al., as understood the traversal relies on amendments. Claim 1 has been amended to recite “in the case where the oxygen carrier comprises iron (Fe), the oxygen carrier has a crystal structure having a spinel structure, wherein, in the case where the oxygen carrier comprises cerium (Ce), the reducing agent further comprises a composite metal oxide represented by the formula Ce1-x(M)xOy”. Applicant argues “Kuhn discloses a catalyst that combines an oxide having a perovskite-type crystal structure (LSF crystal containing La, Sr, and Fe) with an oxide support. However, the reference does not disclose feature (b) that "in the case where the oxygen carrier comprises iron (Fe), the oxygen carrier has a crystal structure having a spinel structure".” [Remarks, Page 6, Paragraph 7] and “Kuhn does not disclose an oxygen carrier comprising cerium (Ce), wherein "the reducing agent further comprises a composite metal oxide represented by the formula Ce1-x(M)xOy", according to amended claim 1. Thus, Kuhn fails to disclose feature (c) of amended claim 1 from claim 5.” [Remarks, Page 6, Paragraph 8]. This is persuasive. The rejections have been WITHDRAWN.
With respect to the rejection of Claims 1 and 5-7 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 20150190793 A1 Swallow et al., as understood the traversal relies on amendments. Claim 1 has been amended to recite “wherein the reducing agent is used in production of the product gas containing carbon monoxide, and the reducing agent is brought into contact with the raw material gas containing carbon dioxide to reduce the carbon dioxide to produce the product gas.”. Applicant argues “Swallow does not disclose or suggest a reducing agent having feature (d) [the above quoted portion of Claim 1] from non- rejected claim 8. A person having ordinary skill in the art would recognize the Swallow fails to disclose or suggest each feature of the reducing agent of amended claim 1. Therefore, the reducing agent of claim 1, as a whole, would not have been obvious over the reference.” [Remarks, Page 7, Paragraph 5-7]. This is unpersuasive. The above cited portion of Claim 1 is essentially identical to the preamble of Claim 1 “A reducing agent for use in production of a product gas containing carbon monoxide, the reducing agent being brought into contact with a raw material gas containing carbon dioxide to reduce the carbon dioxide to produce the product gas” which the previous Office Action [Office Action dated 10/27/2025, Page 8, Paragraph 4] established as intended use. The Applicant does not argue that these limitations, either presented as a preamble of Claim 1 or later in the Claim, establish a structural difference over the prior art. The rejections are MAINTAINED.
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.
Claim(s) 1, 5-7 and 12 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 20150190793 A1 Swallow et al. Claim 1 recites “A reducing agent for use in production of a product gas containing carbon monoxide, the reducing agent being brought into contact with a raw material gas containing carbon dioxide to reduce the carbon dioxide to produce the product gas”. However this is understood as intended use. MPEP 2111.02.II states “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.” Here, the limitations of the claimed invention are fully set forth in the body of the claim and the intended use of producing carbon monoxide from a reaction with carbon dioxide does not suggest structural limitations.
Claim 1 requires “the reducing agent comprising: an oxygen carrier having oxygen ionic conductivity, and a basic oxide supported on the oxygen carrier”. Regarding the oxygen carrier Claim 1 further requires “wherein the oxygen carrier comprises at least one metal selected from the group consisting of iron (Fe) and cerium (Ce)”. Swallow et al. discloses a substrate supporting the rest of the composition “The substrate is preferably a ceramic substrate or a metallic substrate. The ceramic substrate may be made of any suitable refractory material, e.g., alumina, silica, titania, ceria, zirconia, magnesia, zeolites, silicon nitride, silicon carbide, zirconium silicates, magnesium silicates, aluminosilicates and metallo aluminosilicates (such as cordierite and spodumene), or a mixture or mixed oxide of any two or more thereof.” [0010]. Of the substrates listed, ceria is an oxygen carrier as construed by Claim 1. It would have been obvious to one of ordinary skill in the art to have chosen ceria because it is disclosed as effective.
Claim 1 further requires “wherein the basic oxide comprises at least one metal selected from the group consisting of lithium (Li), sodium (Na), potassium (K), magnesium (Mg), manganese (Mn), cobalt (Co), strontium (Sr), and rubidium (Rb)”. Swallow et al. discloses alkali metals or alkali earth metals as a NOx storage component “The first NO storage component preferably comprises alkaline earth metals (such as barium, calcium, strontium, and magnesium), alkali metals (such as potassium, sodium, lithium, and cesium), rare earth metals (such as lanthanum, yttrium, praseodymium and neodymium), or combinations thereof.” [0014]. There is significant overlap between the basic oxides in Claim 1 and the metals disclosed by Swallow et al. Swallow et al. further discloses these metals are oxides “These metals are typically found in the form of oxides” [0014]. Regarding the limitation “a basic oxide supported on the oxygen carrier” Swallow et al. discloses “The first layer comprises a first platinum group metal ("PGM"), a first NOx storage component, and a first support.” [0013]. Therefore it is understood that as part of the first layer the NOx storage component (basic oxide) is supported on the substrate (oxygen carrier).
Claim 1 further requires “wherein, in the case where the oxygen carrier comprises iron (Fe), the oxygen carrier has a crystal structure having a spinel structure”. Swallow et al. discloses cordierite as an oxygen carrier, however as understood cordierite contains iron but does not have the spinel structure. However, it is noted that the inclusion of iron in the oxygen carrier is optional.
Claim 1 further requires “wherein, in the case where the oxygen carrier comprises cerium (Ce), the reducing agent further comprises a composite metal oxide represented by the formula Ce1-x(M)xOy, where M is a metal element with an ionic radius smaller than an ionic radius of Ce with an identical valence number and an identical coordination number, x is a positive real number, and y is a real number from 1 to 4”. The specification of the instant invention provides examples of metals that meet the requirements of M “Examples of such a metal element M include samarium (Sm), zirconium (Zr), hafnium (Hf), yttrium (Y), gadolinium (Gd), niobium (Nb), praseodymium (Pr), lanthanum (La), titanium (Ti), indium (In), neodymium (Nd), and scandium (Sc).” [0033]. Swallow et al. discloses “Most preferably, the first support is an alumina, silica, titania, zirconia, magnesia, ceria, niobia, tantalum oxide, molybdenum oxide, tungsten oxide, a mixed oxide or composite oxide of any two or more thereof (e.g. silica-alumina, magnesia-alumina, ceria-zirconia or aluminaceria-zirconia), and mixtures thereof.” [0015]. It would have been obvious for one of ordinary skill in the art to have chosen ceria-zirconia as the first support because it is listed as effective. It is noted that because in the formula Ce1-x(M)xOy x is not particularly limited all ceria-zirconia blends would satisfy the formula regardless of the Ce:Zr molar ratio. Furthermore Ce1-x(Zr)xOy is understood to have a y value of between 1.5 and 2 (inclusive) because the common oxidation states of Ce are +3 and +4 and the common oxidation states of Zr is +4.
Claim 1 further requires “and the composite metal oxide is supported by the oxygen carrier”. In this embodiment of Swallow et al. the composite metal oxide is the oxygen carrier and is understood to support itself, or alternatively a lower layer of the oxygen carrier supports an upper layer of the composite oxide, both of which are given by the formula Ce1-x(Zr)xOy.
Claim 1 further requires “wherein an amount of the basic oxide is 60 parts by mass or less per 100 parts by mass of the reducing agent.”. Swallow et al. does not limit the amount of basic oxide used in the composition, however they do disclose by means of example 4.8 wt.% Ba, “cordierite substrate monolith is coated with a three layer NOx absorber catalyst formulation comprising a first, lower layer comprising 1 g/in³ alumina, 1 g/in³ particulate ceria, 47 g/ft³ Pt, 9.5 g/ft³ Pd, and 200 g/ft³ Ba; a second layer comprising 1 g/in³ alumina, 1 g/in³ particulate ceria,47 g/ft³ Pt, 9.5 g/ft3 Pd, and 200 g/ft³ Ba; and a third layer comprising 0.5 g/in³ 85 wt. % zirconia doped with rare earth elements and 10 g/ft³ Rh.” [0041]. Assuming 1 ft3 (equivalent to 1728 in3) the total amount of each substance is 3.456 kg alumina, 3.456 kg ceria, 0.094 kg Pt, 0.019 kg Pd, 0.400 kg Ba, 0.864 kg doped zirconia, and 0.010 kg of Rh. This gives a total mass of the washcoat of 8.299 kg meaning it would be 4.8 wt.% Ba (0.400/8.299 = 0.048). Whether the mass is measured as Ba or BaO the result is well below the 60% required by Claim 1. Furthermore the substrate was not factored into this calculation but would only further lower the basic oxide mass percent, placing it further within the range of Claim 1.
Claim 1 further requires “and wherein the reducing agent is used in production of the product gas containing carbon monoxide, and the reducing agent is brought into contact with the raw material gas containing carbon dioxide to reduce the carbon dioxide to produce the product gas.”. However this merely restates the preamble, which is considered intended use (see above) and is not relevant to claim limitations.
Claim 5 requires “wherein, in the case where the oxygen carrier comprises iron (Fe), the oxygen carrier further comprises cerium (Ce), and the reducing agent further comprises a composite metal oxide represented by the formula Ce1-x(M)xOy, where M is a metal element with an ionic radius smaller than an ionic radius of Ce with an identical valence number and an identical coordination number, x is a positive real number, and y is a real number from 1 to 4, and the composite metal oxide is supported by the oxygen carrier”. However it is noted that neither Claim 1 nor Claim 5/1 actually require the oxygen carrier comprises iron. Therefore the embodiment of Swallow et al. that teaches Claim 1 (see above) is relied upon to teach Claim 5 in view of Claim 1 (Claim 5/1).
Claim 6 requires “a difference between the ionic radius of Ce and the ionic radius of the metal element M is greater than 0 pm and 47 pm or less when the valence number is 3 and the coordination number is 6, and greater than 0 pm and 24 pm or less when the valence number is 4 and the coordination number is 8.”. As discussed above (see Claim 1) zirconium is disclosed as an element M which satisfies this requirement and Swallow et al. discloses ceria-zirconia.
Claim 7 requires “the metal element M is at least one selected from the group consisting of samarium (Sm), zirconium (Zr), and hafnium (Hf).”. Swallow et al. discloses ceria-zirconia (see Claim 1).
Claim 12 requires “wherein an average particle size of the reducing agent is from 1 µm to 5 mm.”. Swallow et al. discloses “The washcoating is preferably performed by first slurrying finely divided particles of the supported PGM (or just the first support) and the first NOx adsorbent in an appropriate solvent, preferably water, to form the slurry. … Preferably, the particles are milled or subject to another comminution process in order to ensure that substantially all of the solid particles have a particle size of less than 20 microns in an average diameter, prior to forming the slurry.” [0025]. The range (less than 20 µm) presented by Swallow et al. overlaps significantly with the range claimed.
Claim(s) 1, 5, 9-11 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 20160296916 A1 Kim et al., in view of US 20200139351 A1 Kuhn et al. Claim 1 requires “A reducing agent for use in production of a product gas containing carbon monoxide, the reducing agent being brought into contact with a raw material gas containing carbon dioxide to reduce the carbon dioxide to produce the product gas”. Kim et al. discloses “An object of the present disclosure is to provide a catalyst for a reverse water gas shift reaction, which uses an oxide that is capable of repeated redox reaction under the atmosphere of hydrogen and carbon dioxide as reactant gas, … , has high carbon dioxide conversion and carbon monoxide selectivity.” [0014].
Claim 1 further requires “the reducing agent comprising: an oxygen carrier having oxygen ionic conductivity, and a basic oxide supported on the oxygen carrier”. Kim et al. discloses an oxygen carrier having oxygen ionic conductivity but is silent towards a basic oxide “In order to achieve the object, the present disclosure provides a composite oxide catalyst composed of a compound of Ce1-xMxO2-0.5x and Fe2O3 as a catalyst for a reverse water gas shift reaction, in which M is one element selected from the group consisting of Y, La, Nd, Sm, and Gd, and x is in a range of 0≤x≤0.5.” [0015]. Both Ce1-xMxO2-0.5x and Fe2O3 are understood to be an oxygen carrier having oxygen ionic conductivity.
Claim 1 further requires “wherein the oxygen carrier comprises at least one metal selected from the group consisting of iron (Fe) and cerium (Ce)”. Kim et al. discloses an oxygen carrier consisting of both iron and cerium (see above).
Claim 1 further requires “wherein, in the case where the oxygen carrier comprises iron (Fe), the oxygen carrier has a crystal structure having a spinel structure”. Kim et al. is silent towards spinel structure, however this is understood to be an inherent property of Fe2O3.
Claim 1 further requires “wherein, in the case where the oxygen carrier comprises cerium (Ce), the reducing agent further comprises a composite metal oxide represented by the formula Ce1-x(M)xOy, where M is a metal element with an ionic radius smaller than an ionic radius of Ce with an identical valence number and an identical coordination number, x is a positive real number, and y is a real number from 1 to 4”. The specification of the instant invention provides examples of metals that meet the requirements of M “Examples of such a metal element M include samarium (Sm), zirconium (Zr), hafnium (Hf), yttrium (Y), gadolinium (Gd), niobium (Nb), praseodymium (Pr), lanthanum (La), titanium (Ti), indium (In), neodymium (Nd), and scandium (Sc).” [0033]. Kim et al. discloses “M is one element selected from the group consisting of Y, La, Nd, Sm, and Gd” [0015].
Claim 1 further requires “and the composite metal oxide is supported by the oxygen carrier”. Kim et al. discloses “After 60 mol % of Fe2O3, and 40 mol % of the Ce1-xGdxO2-0.5x powder were each weighed, a composite powder was prepared by homogeneously mixing and grinding using a ball mill, and drying the product in an oven at 80° C. for 24 hours. 3 g of the composite powder was uniformly dispersed on 0.3 g of quartz wool, and the product was placed in the middle of a quartz reactor Since a Fe2O3-GDC composite powder needs to be pretreated under the reducing atmosphere in order to function as a catalyst for reduction of carbon dioxide through a reverse water gas shift reaction, the temperature was increased at a heating rate of 5°C/min, and a 5% H/95% Ar gas was injected at 300 sccm at 400° C. for 1 hour.” [0041]. This treatment is understood to create a mixture of Ce1-xGdxO2-0.5x supported on particles of Fe2O3, Ce1-xGdxO2-0.5x particles supported on quartz wool, Fe2O3 particles supported on Ce1-xGdxO2-0.5x, and Fe2O3 particles supported on quartz wool.
Claim 1 further requires “wherein the reducing agent is used in production of the product gas containing carbon monoxide, and the reducing agent is brought into contact with the raw material gas containing carbon dioxide to reduce the carbon dioxide to produce the product gas.”. Kim et al. discloses “An object of the present disclosure is to provide a catalyst for a reverse water gas shift reaction, which uses an oxide that is capable of repeated redox reaction under the atmosphere of hydrogen and carbon dioxide as reactant gas, … , has high carbon dioxide conversion and carbon monoxide selectivity.” [0014].
Regarding the limitations not taught by Kim et al., namely the basic oxide, Kuhn et al. is similarly directed to catalyst for performing the reverse water gas shift reaction “In a further aspect, the disclosure relates to a method for converting CO2 to CO comprising contacting H2 with the catalyst composite comprising a perovskite-oxide and an oxide support, whereby the perovskite-oxide is reduced, and whereby H2, is oxidized to produce H2O and contacting CO2, with the catalyst composite, whereby the reduced perovskite-oxide is oxidized, and whereby CO2 is reduced to produce CO.” [0011].
Claim 1 requires “the reducing agent comprising: an oxygen carrier having oxygen ionic conductivity, and a basic oxide supported on the oxygen carrier, wherein the basic oxide comprises at least one metal selected from the group consisting of lithium (Li), sodium (Na), potassium (K), magnesium (Mg), manganese (Mn), cobalt (Co), strontium (Sr), and rubidium (Rb)”. Kuhn et al. discloses “The disclosed perovskite - oxide may have a formula of ABO3. In some embodiments , A is selected from the group consisting of Pb, Ca, Mg, Be, Sr, Ba, La, K, and Na or a combination thereof … . In some embodiments, the perovskite - oxide is La0.75Sr0.25FeO3” [0009].
Claim 1 further requires “wherein an amount of the basic oxide is 60 parts by mass or less per 100 parts by mass of the reducing agent”. Kuhn et al. discloses “a weight ratio of the perovskite-oxide [basic oxide] to the oxide support is from 10:90 to 90:10.” [0010], which is equivalent to saying the basic oxide is 10 to 90 parts by mass per 100 parts by mass of the reducing agent. This range overlaps significantly with the claimed range of less than 60 parts by mass.
It would have been obvious for one of ordinary skill in the art to have combined the basic oxide of Kuhn et al. with the oxygen carrier of Kim et al. for at least the reason that they are both directed to solving the same problem: performing the reverse water gas shift reaction. Furthermore the support of Kuhn et al. includes ceria (“In some embodiments, the oxide support is CeO2, ZrO2, Al2O3, SiO2, TiO2, or a combination thereof” [0010]) which is structurally very similar to the doped ceria disclosed by Kim et al. (“Ce1-xMxO2-0.5x” [0015]).
The motivation to have included the perovskite-oxide of Kuhn et al. with the catalyst of Kim et al. is to improve the oxygen vacant sites of the material. Both Kuhn et al. (“Successful RWGS - CL is contingent on generation of oxygen vacant active sites throughout the perovskite surface and bulk during the reduction step” [0146]) and Kim et al. (“In addition, the composite oxide catalyst of the present disclosure may facilitate the storage and transport of activated oxide during the redox reaction by using a compound of Ce1-xMxO2-0.5x, which is an oxygen storage material including oxygen vacancies in the lattice, and as a result, may improve the catalytic efficiency.” [0024]) recognize the critical importance of oxygen vacant sites for the reverse water gas shift reaction. Kuhn et al. further discloses “the activity of oxygen vacant sites towards CO formation was closely related to the net number of oxygen vacancies present at any time. CO2 adsorption strength over a perovskite-oxide increased with the extent of surface oxygen vacancies, reflecting higher probability of conversion.” [0146] which would motivate one of ordinary skill in the art to have used a support that could maximize oxygen vacant sites to increase product conversion. Kim et al. discloses “The present disclosure intends to improve the catalytic activity by substituting with a solute atom having a lower atomic valence than the solvent atom Ce4+ to form oxygen vacancies” [0025]. Therefore one of ordinary skill in the art would have been able to achieve a composite material of a perovskite-oxide of Kuhn et al. supported on/by the catalyst of Kim et al. which would have had an increase in oxygen vacant sites compared to either material alone, and would be predicted to increase reactivity/selectivity towards CO production.
Claim 5 requires “wherein, in the case where the oxygen carrier comprises iron (Fe), the oxygen carrier further comprises cerium (Ce), and the reducing agent further comprises a composite metal oxide represented by the formula Ce1-x(M)xOy, where M is a metal element with an ionic radius smaller than an ionic radius of Ce with an identical valence number and an identical coordination number, x is a positive real number, and y is a real number from 1 to 4, and the composite metal oxide is supported by the oxygen carrier”. Kim et al. discloses the complex metal oxide Ce1-xMxO2-0.5x supported on an oxygen carrier comprising Fe (see Claim 1).
Claim 9 requires “the reducing agent is an oxidized reducing agent, and the oxidized reducing agent is reduced by being brought into contact with a reducing gas containing hydrogen.”. Kim et al. discloses “As illustrated in FIG. 1, the oxidized Fe2O3, is capable of being reduced to the original state such as Fe3O4, FeO or Fe metal under the atmosphere of hydrogen, which is another reactant gas for a reverse water gas shift reaction. Moreover, the reduced Fe-based material serves as a reducing agent, which again reduces carbon dioxide to carbon monoxide. In other words, the Fe-based catalyst circulates the redox reaction under the atmosphere of hydrogen and carbon dioxide” [0023].
Claim 10 requires “the reducing agent is used separately in reaction steps of a reduction reaction of carbon dioxide and a reduction reaction of the oxidized reducing agent”. Khun et al. discloses “Another aspect of the invention provides a method for converting CO2 to CO comprising (a) contacting H2 with the catalyst composite of claim 1 , whereby the perovskite-oxide is reduced, and whereby H2 is oxidized to produce H2O and (b) contacting CO2 with the catalyst composite, whereby the reduced perovskite-oxide is oxidized, and whereby CO2 is reduced to produce CO.” [0114]. Note that step a and b are separate steps.
Claim 11 requires “A method for producing a gas, the method comprising reducing carbon dioxide by bringing the reducing agent described in claim 1 into contact with a raw material gas containing the carbon dioxide, to produce a product gas containing carbon monoxide.”. Khun et al. discloses “The present disclosure relates to a catalyst composite containing a perovskite-oxide and an oxide support, and the use of such catalyst composite for converting carbon dioxide (CO2) to carbon monoxide (CO) in an industrial scale process.” [0060].
Conclusion
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/JOSHUA MAXWELL SPEER/
Examiner
Art Unit 1736
/DANIEL BERNS/Primary Examiner, Art Unit 1736
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