DETAILED ACTION
Notice of Pre-AIA or AIA Status
1. 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
2. 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.
3. 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.
4. Claims 1, 2, and 4 are rejected under 35 U.S.C. 103 as being unpatentable over Urgeghe et al. and Ardizzone et al.
Urgeghe et al. (US Pub. No. 2011/0209992 A1) is directed toward the electrode for electrolysis cell (title). Ardizzone et al. (“Composite ternary SnO2–IrO2–Ta2O5 oxide electrocatalysts,” J. Electroanal. Chem. 2006, 589, 160-166) is directed toward a composite mixed oxide OER catalyst (pg. 160: abstract).
Regarding Claim 1, Urgeghe et al. discloses an electrode (abstract, Claim 1, and Ex. B07 on Table 1) comprising a coating that contains a mixed metal oxide (abstract and ¶7-10, Table 1) on a valve metal substrate (¶7-10, e.g.: titanium mesh). Urgeghe et al. further describes an intermediate layer whose purpose is to provide increased corrosion resistance, increased electrical conductivity, and better adhesion (¶16) comprising a titanium component and a tantalum component in the form of oxides (¶16) or an alloy when present in the substrate (¶13) as per Ex. B07. Urgeghe et al. further discloses a broader composition range of a mixed metal oxide catalyst layer comprising oxides of tin (50-70%), ruthenium (5-20%), iridium (5-20%), palladium (1-10%) and niobium (0.5-5%) with the parenthetical values being elementary molar ratios (¶10, ¶13, Claim 1 and Claim 9). Table 1 discloses a particular example composition (B07 deposited on top of Ti/Ta intermediate layer), wherein the mixture of oxides comprises 51% Sn, 19.5% Ru, 19.5% Ir, 5% Pd, and 5% Nb.
While Urgeghe et al. does not disclose the use Ta in the catalyst layer, the use of Ta (oxide) doped into OER catalyst is found in Ardizzone et al. In particular, Ardizzone et al. is directed toward doping of SnO2-IrO2 OER catalysts (pg. 160: abstract). Ardizzone discloses the sol-gel synthesis of a mixed metal oxide OER catalyst comprising Sn, Ir, and Ta (pg. 161: 2. Experimental section) with different levels of Ir-doping (i.e.: 0.03, 0.07, and 0.15 atomic percent) and supported on titanium (particles). The exemplary composition of Ardizzone et al. has a formula of Sn0.78Ir0.15Ta0.07O2.175 as determined by XRD (Fig. 1) which makes the ratio of metallic elements comparable to the ranges disclosed in Urgeghe et al. According to the conclusion section of Ardizzone, Ta-doping of SnO2-IrO2 nanostructured composites provide the superior properties in expanding the surface area, improving the electronic conductance and the charge storage capacitance, and promoting the surface enrichment of iridium. These further translate into excellent electrocatalytic properties for OER in acid electrolyte, even at low Ir content (pg. 165).
Based on the disclosure of Ardizzone et al., it would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the catalyst composition of Urgeghe by adding Ta with the reasonable expectation of improving the OER catalytic properties due the lower electrical resistance and Ir-surface enrichment.
When the composition of Urgeghe et al. and Ardizzone et al. is modified with Ta recast in the form of the limitation of Claim 1 of the instant application, the result is: 51% Sn, 39% Ru+Ir (with 50% Ir over total of Ru and Ir) and 7% Ta which meet the elemental composition limitations of Claim 1 (i.e.: the molar ratio of metal elements in the mixed metal oxide is 35 to 48% Ir+Ru, 45 to 60% Sn, and 3 to 9% Ta with the molar ratio of the iridium element to the total of the iridium element and the ruthenium element being 32 to 60% inclusive). It has been held that prima facie case of obviousness exists when the prior art discloses an example that overlaps or contains the claimed range. See MPEP 2144.05(I).
Regarding Claim 2, Urgeghe et al. in view of Ardizzone et al. discloses the electrode according to Claim 1, wherein the molar ratio of the metal elements in the mixed metal oxide is 12 to 25% of the iridium element, 18 to 29% of the ruthenium element, 45 to 60% of the tin element, and 3 to 9% of the tantalum element, and the molar ratio of the iridium element to the total of the iridium element and the ruthenium element in the mixed metal oxide is 33 to 52% inclusive as evidenced by the combination of Urgeghe et al. and Ardizzone et al. with the composition of 51% Sn, 19.5% Ru, 19.5% Ir (with 50% Ir over total of Ru and Ir), and 7% Ta which meet the elemental composition limitations of Claim 2 as listed above. It has been held that prima facie case of obviousness exists when the prior art discloses an example that overlaps or contains the claimed range. See MPEP 2144.05(I).
Regarding Claim 4, Urgeghe et al. in view of Ardizzone et al. discloses the electrode according Claim 1, wherein the electrode is for oxygen generation in an electrolysis process as supported by Table 1 which indicates that the catalyst of Urgeghe et al. and Fig. 5 in Ardizzone et al. (pg. 164).
5. Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Urgeghe et al. and Ardizzone et al. as applied to Claim 1, and further in view of Teles et al.
Mitsushima et al. (US Pub. No. 2017/0321331 A1) is directed toward an oxygen generating anode (title). Urgeghe et al. (US Pub. No. 2011/0209992 A1) is directed toward the electrode for electrolysis cell (title). Teles et al. (“Supercapacitive properties, anomalous diffusion, and porous behavior of nanostructured mixed metal oxides containing Sn, Ru, and Ir,” Electrochimica Acta 2019, 295, 302-315) is directed toward nanostructured mixed metal oxides containing Sn, Ru, and Ir (pg. 302: title).
Regarding Claim 3, Urgeghe et al. in view of Ardizzone et al. discloses the electrode according to Claim 1 with a mixed metal oxide layer of tin (50-70% from Urgeghe et al.), iridium (5-20% from Urgeghe et al.), ruthenium (5-20% from Urgeghe et al), and tantalum (7% from Ardizzone et al.) with the parenthetical values being elementary molar ratios as explained in Claim 1 above. However, the combination of references does not teach a Ru elemental range of 24-28 % as required by Claim 3 (but rather 5-20%).
Teles et al. is directed toward mixed metal oxides comprised of Sn, Ru, and Ir (pg. 302: title). The compositions evaluated for electrochemical activity are listed in Table 1 (pg. 306) and are synthesized by drop casting onto a titanium substrate and calcining (pg. 303: 2.1 Electrode preparation). The method of Teles et al. of electrode preparation is analogous to the preparation method of Urgeghe et al. and Ardizzone et al. Ir and Ru are very expensive, but offer unique electrochemical properties, with the former (i.e.: Ir) being more expensive (pg. 304: introduction). Therefore, Teles evaluate the effect of Ru/Ir ratio mixed metal oxides with tin oxide as the cheaper component. As per Table 1, the ratio of Sn was held constant at 50 elemental % with the remainder being a mixture of Ru and Ir. It was found that higher levels of Ir improved the electrochemical properties of the mixed metal oxide (FIG. 3) which results in an increasingly expensive catalyst. Notably, the compositions of 50% Sn/10%Ir /40%Ru and 50%Sn/ 20%Ir/ 30%Ru had very similar electrochemical properties (FIG. 3A) and charge storage performance (FIG. 4). This shows that reducing the level of Ir by increasing the Ru levels results in a catalyst with similar electrochemical properties at a lower cost. Thus, the level of Ru is a results-effective, i.e., a variable which achieves a recognized result, and the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation (See MPEP 2144.0.II.B.). Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have discovered the optimum or workable ranges of the Ru elemental ratio, including values within the claimed range, through routine experimentation. One would have been motivated to do so in order to have formed an OER catalyst with good electrochemical performance at a lower financial cost.
The final limitation of Claim 3, that is, the molar ratio of the iridium element to the total of the iridium element and the ruthenium element in the mixed metal oxide is 34 to 40% inclusive is met as a result of the optimization of Ru meeting the claim limitations of the Ru elemental ratio.
6. Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Mitsushima et al. and Urgeghe et al.
Mitsushima et al. (US Pub. No. 2017/0321331 A1) is directed toward an oxygen generating anode (title). Urgeghe et al. (US Pub. No. 2011/0209992 A1) is directed toward the electrode for electrolysis cell (title).
Regarding Claim 5, Mitsushima et al. discloses a method for manufacturing an electrode (abstract and ¶53-61). The method of Mitsushima et al. comprises
a step for forming, on a surface of a valve metal substrate (i.e.: titanium in ¶53), an intermediate layer precursor that contains an alloy that contains a titanium component and a tantalum component by means of an arc ion plating method as indicated in ¶22, ¶31, ¶34, and FIG. 1 (e.g.: Ti-Ta intermediate layer). The interlayer provides improved corrosion resistance
Mitsushima et al. discloses the application of a catalyst layer selected from oxides, nitrides and carbides of the at least one metal selected from the group consisting of elements belonging to groups 4, 5 and 13 of the periodic table for oxygen evolution. These elements include Ta and Ir as per Ex. 1 where the ratio of 85 Ir to 15 Ta (¶61). Mitsushima et al. further describes the following steps:
a step for forming a coating precursor by applying, to the surface of the intermediate layer precursor, a solution containing iridium ions (from iridium tetrachloride) and tantalum ions (from tantalum pentachloride) and drying said solution as per Ex. 1 in ¶61; and
a step for heat processing in an atmosphere containing oxygen for 30 minutes to two hours at a temperature of 400 to 600°C by using an annealing temperature of 500-550°C and bake times of 20 minutes to 1 hour (¶61 and ¶76) .
However, Mitsushima et al. does not disclose the use of Sn and Ru in the OER catalyst precursor solution. Ir is known to be both rare and expensive, so one of ordinary skill in the art would be motivated to reduce the Ir content in the OER catalyst.
Urgeghe et al. discloses an electrode (abstract, Claim 1, and Ex. B07 on Table 1) comprising a coating that contains a mixed metal oxide (abstract and ¶7-10, Table 1) on a valve metal substrate (¶7-10, e.g.: titanium mesh). Urgeghe et al. further describes an intermediate layer whose purpose is to provide increased corrosion resistance, increased electrical conductivity, and better adhesion (¶16) comprising a titanium component and a tantalum component in the form of oxides (¶16) or an alloy when present in the substrate (¶13) as per Ex. B07. Urgeghe et al. further discloses a broader composition range of a mixed metal oxide catalyst layer comprising oxides of tin (50-70%), ruthenium (5-20%), iridium (5-20%), palladium (1-10%) and niobium (0.5-5%) with the parenthetical values being elementary molar ratios (¶10, ¶13, Claim 1 and Claim 9). In ¶26-¶40, Urgeghe et al. teaches a method of forming the catalyst using solutions of ions (e.g.: Ir, Ru, Sn, and Nb) dissolved in a solvent, applying that solution to the substrate, drying, and then annealing. Thus, the methods of Urgeghe et al. and Mitsushima et al. are substantially identical.
Given the above explanation, it would be reasonable for one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the catalyst solution of Mitsushima et al. by adding Sn and Ru as taught by Urgeghe et al. with the reasonable expectation of forming an effective OER catalyst at a lower cost by reducing the amount of Ir.
Conclusion
7. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Hutchings et al. (“A structural investigation into the stabilized oxygen evolution catalyst,” J. Mater. Sci. 1984, 19, 3987-3994) is directed toward Sn/Ir/Ru oxide catalyst for OER (pg. 3987: abstract). Lin et al. (“Oxygen Evolution on Ir-Ru-Sn Ternary Oxide-Coated Electrodes in H2SO4 Solution,” J. Electrochem. Soc. 1993, 140, 2265-2271) is directed toward Sn/Ru/Ir oxide OER catalysts (pg. 2265: abstract). Murrieta et al. (“Electrosynthesis of hypochlorous acid in a filter-press electrolyzer and its modeling in dilute chloride solutions,” J. Electroanal. Chem. 2021, 892, article 115286, pg. 1-10) is directed toward is directed toward Sn/Ru/Ir oxide electrocatalysts (pg. 1: abstract).
8. Any inquiry concerning this communication or earlier communications from the examiner should be directed to KEVIN SYLVESTER whose telephone number is 703-756-5536. The examiner can normally be reached Mon - Fri 8:15 AM to 4:30 PM EST.
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/KEVIN SYLVESTER/Examiner, Art Unit 1794
/JAMES LIN/Supervisory Patent Examiner, Art Unit 1794
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