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 Objections
Claim 121 is objected to because of the following informalities:
Claim 121 line 3 recites “the reacting step”, but should recite “the chemically reacting” or “the chemically reacting step” to match the terminology used in claim 94.
Appropriate correction is required.
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.
Claims 108, 109, and 121 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor regards as the invention.
Regarding claims 108, 109, and 121, these claims recite the limitation "the carbon-containing solution". There is insufficient antecedent basis for this limitation in the claim. Specifically, claim 94, from which these claims depend, does not recite “a carbon-containing solution”. It is therefore unclear to what the limitation “the carbon-containing solution” refers.
Claims 108, 109, and 121 are therefore 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 94-97, 108, 112-113, 116, and 119 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Li et al. (“CO2 Electroreduction from Carbonate Electrolyte” ACS Energy Lett. 2019, 4, 1427−1431 and SI).
Regarding claim 94, Li teaches a method of electrolyzing a carbon-containing ion (title), the method comprising:
applying an electrical potential (§ titled “Electrochemical characterizations” on p. S2 and see Fig. 1) between an anode (“Ni foam was used as the anode catalyst” Id.) and an electrode (“Ag or Cu catalyst was used as the cathode catalyst” Id.) of an electrochemical cell comprising an ion exchange membrane separating the anode and the electrode (“a bipolar membrane … was used as the separator” Id.), wherein the electrode comprises a metallic material having a plurality of pores distributed throughout the electrode (“The Ag and Cu catalysts were characterized … showing uniform coating over the entire carbon paper and porous structure down to the 100s of nm scale” § titled “Materials characterizations” on p. S2 and see Figs. S1-S2);
dissociating, within the ion exchange membrane, water into hydrogen ions and hydroxide ions (“a bipolar membrane (BPM), which consists of a catalyst layer to dissociate water to generate protons and hydroxide anions and directs them to the cathode and anode, respectively” p. 1427 col. 2 para. 2 and “(2)” Fig. 1c, reproduced below);
permeating the hydrogen ions and the hydroxide ions out of the ion exchange membrane, the hydrogen ions permeating towards the electrode and the hydroxide ions permeating towards the anode (Id.);
chemically reacting, at the ion exchange membrane, the hydrogen ions with the carbon-containing ion to form one or more carbon-containing intermediate products (“the BPM proton reacts with carbonate to generate CO2 near the membrane” p. 1427 col. 2 para. 2 and “(3)” Fig. 1c); and
electrochemically reducing, at the electrode, one of the carbon-containing intermediate products to form one or more carbon-containing resulting products (“this is reduced to value-added products via CO2RR” p. 1427 col. 2 para. 2 and “(4)” Fig. 1c).
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Li Fig. 1c
Regarding claim 95, Li further teaches the carbon-containing ion is carbonate (title, “carbonate” p. 1427 col. 2 para. 2, and “(3)” Fig. 1c).
Regarding claim 96, Li anticipates the limitations of claim 94, as described above.
Li further teaches the one or more carbon-containing intermediate products comprises carbon dioxide (“to generate CO2” p. 1427 col. 2 para. 2, and “(3)” Fig. 1c).
Regarding claim 97, Li anticipates the limitations of claim 95, as described above.
Li further teaches the one or more carbon-containing resulting products comprises carbon monoxide (“CO Faradaic efficiency (FE)” para. bridging p. 1427-1428 and “(4)” Fig. 1c).
Regarding claim 108, claim 108 has been interpreted as “wherein the concentration of the carbon-containing ion is in the range of from 0.1M to 6M”.
Li anticipates the limitations of claim 94, as described above.
Li further teaches the concentration of the carbon-containing ion is 1 M, a value within the claimed range (“The catholyte (40ml) was either 1 M K2CO3 …” para. 1 § titled “Electrochemical characterizations” on p. S2).
Regarding claims 112-113, Li anticipates the limitations of claim 94, as described above.
Li further teaches the metallic material is silver (claim 113), a transition metal (claim 112) (“Ag or Cu catalyst was used as the cathode catalyst” (§ titled “Electrochemical characterizations” on p. S2).
Regarding claims 116 and 119, Li anticipates the limitations of claim 94, as described above.
Li further teaches treating the electrode to increase an electrochemically active surface area of the electrode (claim 116), the treating the electrodes comprising depositing a nanosized catalyst on a surface of the electrode, the nanosized catalyst comprising nanoparticles (claim 117) (“Ag catalysts were prepared by spray coating Ag nanoparticle ink onto a sputtered Ag film” p. S2 para. 1).
Claims 94-97, 100-101, 104, 108, 112-113, 116, and 119 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Mallouk et al. (“Electrolysis of CO2 to Syngas in Bipolar Membrane-Based Electrochemical Cells” ACS Energy Lett. 2016, 1, 1149−1153 and SI) and as evidenced by, in the case of claim 104, Toray (“Torayca™ Carbon Paper” 2024).
Regarding claim 94, Mallouk teaches a method of electrolyzing a carbon-containing ion (“Electrolysis was carried out using aqueous bicarbonate” abstract), the method comprising:
applying an electrical potential between an anode and an electrode of an electrochemical cell comprising an ion exchange membrane separating the anode and the electrode (“CO2 electrolysis using NiFeOx and Ag catalysts was first studied in a sandwich cell in which the catalytic electrodes, in contact with liquid electrolytes, were separated by a membrane.” p. 1150 para. bridging cols. 1 and 2 and see Fig. 2b), wherein the electrode comprises a metallic material having a plurality of pores distributed throughout the electrode (“Ag nanoparticle catalysts supported on porous carbon paper” p. 1150 col. 1 para. 3);
dissociating, within the ion exchange membrane, water into hydrogen ions and hydroxide ions (Eq. 5 on p. 1150 col. 2);
permeating the hydrogen ions and the hydroxide ions out of the ion exchange membrane, the hydrogen ions permeating towards the electrode and the hydroxide ions permeating towards the anode (“in the BPM cell, the dissociation of water (reaction 5) drives H+ and OH− ions toward the cathode and anode, respectively” p. 1150 col. 2 between eq. 1 and eq. 2, see also Fig. 2);
chemically reacting, at the ion exchange membrane, the hydrogen ions with the carbon-containing ion to form one or more carbon-containing intermediate products (“reaction of protons with HCO3− ions at the membrane/catholyte interface” para. bridging p. 1150-1151); and
electrochemically reducing, at the electrode, one of the carbon-containing intermediate products to form one or more carbon-containing resulting products (“CO2 reduction to CO and water reduction to H2 at the Ag catalyst” p. 1151 col. 1 para. 1).
Regarding claim 95, Mallouk further teaches the carbon-containing ion is bicarbonate (“Aqueous 0.5 M KHCO3 saturated with CO2 and 0.1 M KOH were circulated through the serpentine cathode and anode flow fields, respectively,” p. 1150 para. bridging cols. 1 and 2 and see Fig. 2b).
Regarding claim 96, Mallouk anticipates the limitations of claim 94, as described above.
Mallouk further teaches the one or more carbon-containing intermediate products comprises carbon dioxide (“reaction of protons with HCO3− ions at the membrane/catholyte interface” para. bridging p. 1150-1151; as evidenced by e.g., the instant specification, the reaction of protons with HCO3- ions produces carbon dioxide).
Regarding claim 97, Mallouk anticipates the limitations of claim 95, as described above.
Mallouk further teaches the one or more carbon-containing resulting products comprises carbon monoxide (“CO2 reduction to CO and water reduction to H2 at the Ag catalyst” p. 1151 col. 1 para. 1).
Regarding claim 100, Mallouk anticipates the limitations of claim 94, as described above.
Mallouk further teaches the faradaic efficiency of the reaction performed at the reducing step is greater than 60%, a value within the claimed range (Fig. 3b and “the CO selectivity was above 60%.” p. 1151 col. 1 para. 1).
Regarding claim 101, Mallouk further teaches the electrical potential applied across the electrodes introduces a current density I/A at the electrode of 50 mA cm-2, a value within the claimed range, where I is electrical current and A is the geometrical surface are of the electrode (“a constant current density of 50 mA/cm2” Fig. 3 caption and “50 mA/cm2 current density” p. 1151 col. 1 para. 1).
Regarding claim 104, Mallouk anticipates the limitations of claim 94, as described above.
Mallouk further teaches the porosity of the electrode is 78%, a value within the claimed range (“Carbon paper (Toray 120)” p. S1 § titled “Materials”, as evidenced by Toray, Toray 120 carbon paper has a porosity of 78%).
Regarding claim 108, claim 108 has been interpreted as “wherein the concentration of the carbon-containing ion is in the range of from 0.1M to 6M”.
Mallouk anticipates the limitations of claim 94, as described above.
Mallouk further teaches the concentration of the carbon-containing ion is 0.5 M, a value within the claimed range (“Aqueous 0.5 M KHCO3 saturated with CO2 and 0.1 M KOH were circulated through the serpentine cathode and anode flow fields, respectively,” p. 1150 para. bridging cols. 1 and 2).
Regarding claims 112 and 113, Mallouk anticipates the limitations of claim 94, as described above.
Mallouk further teaches the metallic material is silver (claim 113), a transition metal (claim 112) (“CO2 reduction to CO and water reduction to H2 at the Ag catalyst” p. 1151 col. 1 para. 1).
Regarding claims 116 and 119, Mallouk anticipates the limitations of claim 94, as described above.
Mallouk further teaches treating the electrode to increase an electrochemically active surface area of the electrode (claim 116), the treating the electrodes comprising depositing a nanosized catalyst on a surface of the electrode, the nanosized catalyst comprising nanoparticles (claim 117) (“Ag nanoparticles were drop-cast onto the carbon paper. …” para. bridging p. S1-S2).
Claim Rejections - 35 USC § 102/103
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 110 is rejected under 35 U.S.C. 102(a)(1) as anticipated by or, in the alternative, under 35 U.S.C. 103 as obvious over Li et al. (“CO2 Electroreduction from Carbonate Electrolyte” ACS Energy Lett. 2019, 4, 1427−1431 and SI).
Regarding claim 110, Li anticipates the limitations of claim 94, as described above.
Li further teaches the operating temperature is about 20 °C (see below), a value within the claimed range or, alternatively, a range overlapping the claimed range.
A range in the prior art overlapping a claimed range establishes a prima facie case of obviousness (MPEP § 2144.05).
Li therefore anticipates or, in the alternative, renders obvious the limitation “the operating temperature is in the range of from 20 °C to 80 °C”.
Regarding the limitation “the operating temperature is in the range of from 20 °C to 80 °C”, Li does not specify the operating temperature. Li therefore implicitly teaches the method is performed at room temperature i.e., about 20 °C, see excerpt from Oxford Dictionary of Biochemistry and Molecular Biology (2nd ed.), below.
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Claim 110 is rejected under 35 U.S.C. 102(a)(1) as anticipated by or, in the alternative, under 35 U.S.C. 103 as obvious over Mallouk et al. (“Electrolysis of CO2 to Syngas in Bipolar Membrane-Based Electrochemical Cells” ACS Energy Lett. 2016, 1, 1149−1153 and SI).
Regarding claim 110, Mallouk anticipates the limitations of claim 94, as described above.
Mallouk further teaches the operating temperature is about 20 °C (see below), a value within the claimed range or, alternatively, a range overlapping the claimed range.
A range in the prior art overlapping a claimed range establishes a prima facie case of obviousness (MPEP § 2144.05).
Mallouk therefore anticipates or, in the alternative, renders obvious the limitation “the operating temperature is in the range of from 20 °C to 80 °C”.
Regarding the limitation “the operating temperature is in the range of from 20 °C to 80 °C”, Mallouk does not specify the operating temperature for the method using aqueous bicarbonate. Mallouk therefore implicitly teaches the method is performed at room temperature i.e., about 20 °C, see excerpt from Oxford Dictionary of Biochemistry and Molecular Biology (2nd ed.), below.
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Claim Rejections - 35 USC § 103
Claim 102 is rejected under 35 U.S.C. 103 as being unpatentable over Mallouk et al. (“Electrolysis of CO2 to Syngas in Bipolar Membrane-Based Electrochemical Cells” ACS Energy Lett. 2016, 1, 1149−1153 and SI) in view of Krause (US Pat. Pub. 2020/0131649 A1).
Regarding claim 102, Mallouk anticipates the limitations of claim 94 as described above in the rejection under 35 U.S.C. § 102(a)(1), incorporated herein by reference.
Mallouk does not teach a surface of the electrode is hydrophilic.
However, Krause teaches a method for improving the wettability of a gas diffusion electrode (“The use of ion exchange resins … increases the proportions of the hydrophilic regions of the electrode, which can increase electrolyte transport through the electrode” para. 121 and see paras. 123 and 141) for carbon dioxide reduction (title) in a bicarbonate electrolyte (“The catholyte was a 1 M KHCO3 solution” para. 268), by applying a hydrophilic coating to the surface of the electrode facing the catholyte (para. 121).
As Mallouk and Krause each teach methods for the electrochemical reduction of carbon dioxide in membrane cells using bicarbonate electrolytes, Mallouk and Krause are analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mallouk, such that a surface of the electrode is hydrophilic, as taught by Krause. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable benefit of improving contact between the electrode and the catholyte, as taught by Krause. Furthermore, combining prior art elements according to known methods to yield predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(A)).
Claim 106 is rejected under 35 U.S.C. 103 as being unpatentable over Mallouk et al. (“Electrolysis of CO2 to Syngas in Bipolar Membrane-Based Electrochemical Cells” ACS Energy Lett. 2016, 1, 1149−1153 and SI) in view of Yoon et al. (“Tuning of Silver Catalyst Mesostructure Promotes Selective Carbon Dioxide Conversion into Fuels” Angew. Chem. Int. Ed. 2016, 55, 15282-15286) and as evidenced by Toray (“Torayca™ Carbon Paper” 2024).
Regarding claim 106, Mallouk anticipates the limitations of claim 94 as described above in the rejection under 35 U.S.C. § 102(a)(1), incorporated herein by reference.
Mallouk does not teach the electrochemically active surface area of the electrode is in the range of from about 0.10 m2/g and about 0.3 m2/g.
Mallouk is silent as to the electrochemically active surface area (ECSA).
However, Yoon teaches a method for improving the Faradaic efficiency of carbon dioxide reduction to carbon monoxide in a bicarbonate catholyte by a silver electrocatalyst (“Faradaic efficiency for CO production as a function of applied potential for Ag films of varying RF. All data were collected in CO2-saturated 0.1 M KHCO3.” Fig. 2 caption and see abstract) by increasing the roughness factor of the electrode to between 43 and 109 (Fig. 2), wherein the roughness factor is defined as the ratio of the ECSA to the geometric surface area of the electrode (“These ECSA values were normalized to the geometric area of each electrode to determine its roughness factor (RF).” p. 15283 col. 1 para. 1).
As Mallouk and Yoon each teach methods for the electrochemical reduction of carbon dioxide using bicarbonate electrolytes and silver catalysts, Mallouk and Yoon are analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mallouk, such that the roughness factor of the electrode is in a range of 43 to 109, as taught by Yoon. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable benefit of improving the Faradaic efficiency of carbon dioxide reduction to carbon monoxide, as taught by Yoon. Furthermore, combining prior art elements according to known methods to yield predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(A)).
A roughness factor of 43 to 109 corresponds to an ECSA of about 0.26 to about 0.66 m2/g, a range overlapping the claimed range, (see calculations below) in modified Mallouk.
A range in the prior art overlapping a claimed range establishes a prima facie case of obviousness (MPEP § 2144.05).
Calculation of ECSA in modified Mallouk: Mallouk teaches the geometrical surface area of the electrodes are 1.0 cm2 (“The geometrical area of both the anode and cathode catalysts was 1 cm2 on the carbon paper” § titled “Full electrolysis cell experiments” on p. S2). The ECSA, as defined by Yoon, for a roughness factor of 43 and 109 are thus 43.0 cm2 and 109 cm2, respectively, in modified Mallouk.
As evidenced by Toray, the thickness of Toray 120 carbon paper is 0.37 mm, and the density is 0.45 g/cm3. The electrodes of Mallouk therefore weigh about 16.7 mg (1.0 cm2 * 0.37 mm * 0.45 g/cm3).
The specific ECSA in modified Mallouk i.e., the ECSA as defined in the instant claim, is thus between about 0.26 m2/g (43 cm2 / 16.7 mg) and 0.66 m2/g (109 cm2 / 16.7 mg).
Claim 107 is rejected under 35 U.S.C. 103 as being unpatentable over Mallouk et al. (“Electrolysis of CO2 to Syngas in Bipolar Membrane-Based Electrochemical Cells” ACS Energy Lett. 2016, 1, 1149−1153 and SI) in view of Ramdin et al. (“High Pressure Electrochemical Reduction of CO2 to Formic Acid/Formate: A Comparison between Bipolar Membranes and Cation Exchange Membranes” Ind. Eng. Chem. Res. 2019, 58, 1834−1847).
Regarding claim 107, Mallouk anticipates the limitations of claim 94 as described above in the rejection under 35 U.S.C. § 102(a)(1), incorporated herein by reference.
Mallouk does not teach the operating pressure at the electrode is in the range of from about 4 atm to about 10 atm.
However, Ramdin teaches the Faradaic efficiency and current density (Fig. 4) of the electrochemical reduction of carbon dioxide in a bipolar membrane cell (abstract) using a bicarbonate electrolyte (“The anolyte, catholyte, flow rate, and electrolysis time were 1 M KOH, 0.5 M KHCO3, 10 mL/min, and 20 min” Fig. 4 caption) can be improved by increasing the pressure at the electrode in the range of about 5 atm to about 50 atm (“5−50 bar” p. 1838 col. 1 para. 1 and see e.g., Fig. 4, note 1 bar is about 1 atm), a range overlapping the claimed range.
As Mallouk and Ramdin each teach methods for the electrochemical reduction of carbon dioxide using a bicarbonate electrolyte in a bipolar membrane cell, Mallouk and Ramdin are analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mallouk, by using a pressure at the electrode in the range of about 5 to about 50 atm, a range overlapping the claimed range, as taught by Ramdin. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable benefit of improving the Faradaic efficiency and current density, as taught by Ramdin. Furthermore, simple substitution of one known element for another (i.e., using the pressure range of Ramdin in place of the pressure used in Mallouk) to achieve predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(B)). A range in the prior art overlapping a claimed range establishes a prima facie case of obviousness (MPEP § 2144.05).
Claim 109 is rejected under 35 U.S.C. 103 as being unpatentable over Mallouk et al. (“Electrolysis of CO2 to Syngas in Bipolar Membrane-Based Electrochemical Cells” ACS Energy Lett. 2016, 1, 1149−1153 and SI) in view of Fontecave (WO 2020127821 A1) and Verma et al. (“The effect of electrolyte composition on the electroreduction of CO2 to CO on Ag based gas diffusion electrodes” Phys. Chem. Chem. Phys. 2016, 18, 7075-7084).
Regarding claim 109, claim 109 has been interpreted as “wherein the concentration of the carbon-containing ion is in the range of from 4M to 6M”.
Mallouk anticipates the limitations of claim 94 as described above in the rejection under 35 U.S.C. § 102(a)(1), incorporated herein by reference.
Mallouk does not teach the concentration of the carbon-containing ion in the carbon-containing solution is in the range of from 4M to 6M.
However, Fontecave teaches a concentration of between 0.01 M and 10 M, a range encompassing the claimed range, is suitable for a bicarbonate catholyte (“The concentration of the salt of hydrogen carbonate advantageously is below 10 M, for example below 1 M, notably below 0.5 M. It can be comprised between 0.01 M and 0.5 M, notably between 0.05 M and 0.2 M.” p. 19 lines 16-18) used in a bipolar membrane cell (“A H-type cell was used with the two compartments being separated by a bipolar exchange membrane” p. 27 lines 5-17) for the electrochemical reduction of carbon dioxide to carbon monoxide (p. 23 line 25 – p. 24 line 5).
As Mallouk and Fontecave each teach methods for the electrochemical reduction of carbon dioxide using a bicarbonate electrolyte in a bipolar membrane cell, Mallouk and Fontecave are analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mallouk, such that the concentration of the carbon-containing ion in the carbon-containing solution is in the range of from 0.01 M to 10 M, a range encompassing the claimed range, as taught by Fontecave. A person having ordinary skill in the art would have been motivated to use this range because Fontecave teaches this range is suitable for a bicarbonate concentration in the catholyte of a method for reducing carbon dioxide to carbon monoxide in a bipolar membrane cell. Simple substitution of one known element for another to achieve predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(B)). Furthermore, use of a material known in the art as suitable for a purpose (i.e., a bicarbonate catholyte having a concentration between 0.01 and 10 M for carbon dioxide reduction in a bipolar membrane cell) establishes a prima facie case of obviousness (MPEP § 2144.07). A range in the prior art encompassing a claimed range establishes a prima facie case of obviousness (MPEP § 2144.05(I)).
Furthermore, Verma teaches that the current density (Fig. 2c-d and Table 1) and Faradaic efficiency (Table 1) of carbon dioxide reduction to carbon monoxide on a silver electrode (abstract) depends on the molar concentration of bicarbonate in the catholyte (Table 1 and abstract). It is therefore considered that the molar concentration of bicarbonate in the catholyte would have been recognized as a result-effective variable by a person having ordinary skill in the art before the effective filing date of the instant application.
It is therefore considered that a person having ordinary skill in the art would have found it obvious to modify the method of Mallouk by using a bicarbonate concentration between 4 M and 6 M as a result of routine optimization within the range taught by Fontecave based on the teachings of Verma (MPEP § 2144.05(II)).
Claims 114 and 115 are rejected under 35 U.S.C. 103 as being unpatentable over Mallouk et al. (“Electrolysis of CO2 to Syngas in Bipolar Membrane-Based Electrochemical Cells” ACS Energy Lett. 2016, 1, 1149−1153 and SI) in view of Yu et al. (“Comparative Study between Pristine Ag and Ag Foam for Electrochemical Synthesis of Syngas with Carbon Dioxide and Water” Catalysts 2019, 9, 57).
Regarding claim 114, Mallouk anticipates the limitations of claim 94 as described above in the rejection under 35 U.S.C. § 102(a)(1), incorporated herein by reference.
Mallouk does not teach the electrode is made from a foam material.
However, Yu teaches a silver foam electrode (“silver (Ag) foam” abstract and § 3.3. para. 1) provides enhanced activity relative to monolithic silver (§ 4) for the electrochemical reduction of carbon dioxide to carbon monoxide (e.g., Fig. 5) in a membrane cell using a bicarbonate electrolyte (§ 3.3. para. 1).
As Mallouk and Yu each teach methods for the electrochemical reduction of carbon dioxide to carbon monoxide using a bicarbonate catholyte and silver cathode in a membrane cell, Mallouk and Yu are analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mallouk, such that the electrode is made from a foam material i.e., silver foam, as taught by Yu. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable result of enhancing the catalytic activity of the electrode, as taught by Yu. Furthermore, simple substitution of one known element for another to achieve predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(B)). Furthermore, use of a material known in the art as suitable for a purpose (i.e., silver foam) establishes a prima facie case of obviousness (MPEP § 2144.07).
Regarding claim 115, Mallouk anticipates the limitations of claim 94 as described above in the rejection under 35 U.S.C. § 102(a)(1), incorporated herein by reference.
Mallouk does not teach the electrode comprises a free-standing silver foam.
However, Yu teaches a free-standing (see below) silver foam electrode (“silver (Ag) foam” abstract and § 3.3. para. 1) provides enhanced selectivity for CO vs. H2 production relative to monolithic silver (§ 4 and Fig. 6) for the electrochemical reduction of carbon dioxide to carbon monoxide (abstract and § 4) in a membrane cell using a bicarbonate electrolyte (§ 3.3. para. 1).
As Mallouk and Yu each teach methods for the electrochemical reduction of carbon dioxide to carbon monoxide using a bicarbonate catholyte and silver cathode in a membrane cell, Mallouk and Yu are analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mallouk, such that the electrode is a free-standing silver foam, as taught by Yu. A person having ordinary skill in the art would have been motivated to make this modification to achieve the predictable result of enhancing the catalytic activity of the electrode, as taught by Yu. Furthermore, simple substitution of one known element for another to achieve predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(B)). Furthermore, use of a material known in the art as suitable for a purpose (i.e., a free-standing silver foam) establishes a prima facie case of obviousness (MPEP § 2144.07).
Regarding the limitation “free-standing silver foam”, Yu teaches the silver foam is used directly as the electrode (§ 3.3. para. 1), was purchased commercially (§ 3.1.), and does not describe any support/substrate for the silver foam or monolithic silver. Yu thus implicitly teaches the silver foam is “free-standing”.
Claims 117-118 are rejected under 35 U.S.C. 103 as being unpatentable over Mallouk et al. (“Electrolysis of CO2 to Syngas in Bipolar Membrane-Based Electrochemical Cells” ACS Energy Lett. 2016, 1, 1149−1153 and SI) in view of Luc et al. (“An Ir-based anode for a practical CO2 electrolyzer” Catalysis Today 288 (2017) 79–84).
Regarding claims 117 and 118, Mallouk anticipates the limitations of claim 116 as described above in the rejection under 35 U.S.C. § 102(a)(1), incorporated herein by reference.
Mallouk does not teach the treating the electrode comprises etching the electrode (claim 117) by immersing the electrode in acid (claim 118).
However, Luc teaches a method for forming a porous silver cathode (“Nanoporous Ag cathode” § 2.2.3.) for carbon dioxide reduction (abstract) in a membrane cell (“a two-compartment cell separated with an anion exchange membrane” § 2.4. para. 1) with a bicarbonate catholyte (“The electrolyte was a 0.5 M aqueous NaHCO3” Id.), wherein the electrode is made nanoporous i.e., the electrochemically active surface area (ECSA) of the cathode is increased, by etching the electrode (“Nanoporous Ag cathodes were fabricated using a modified dealloying technique, which is known to be an effective method to fabricate nanoporous metals.” § 2.2.3.) by immersing it in acid (“the precursor sheets were leached in 1000 mL of 5 wt% HCl for one hour” § 2.2.).
As Mallouk and Luc each teach methods for the electrochemical reduction of carbon dioxide to carbon monoxide using a bicarbonate catholyte and silver cathode in a membrane cell, Mallouk and Luc are analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mallouk, such that the step of treating the electrode to increase an electrochemically active surface area of the electrode comprises etching the electrode (claim 117) by immersing the electrode in acid (claim 118), as taught by Luc. A person having ordinary skill in the art would have been motivated to make this modification because Luc teaches this is an effective method for increasing the electrochemically active surface area of a silver electrode. Furthermore, combining prior art elements according to known methods to yield predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(A)).
Claim 121 is rejected under 35 U.S.C. 103 as being unpatentable over Mallouk et al. (“Electrolysis of CO2 to Syngas in Bipolar Membrane-Based Electrochemical Cells” ACS Energy Lett. 2016, 1, 1149−1153 and SI) in view of Fontecave (WO 2020127821 A1).
Regarding claim 121, claim 121 has been interpreted as “wherein the system is pre-heated to a temperature in the range from about 60 °C to 80 °C prior to the chemically reacting step”.
Mallouk anticipates the limitations of claim 94 as described above in the rejection under 35 U.S.C. § 102(a)(1), incorporated herein by reference.
Mallouk does not teach the system is pre-heated to a temperature in the range from about 60 °C to 80 °C prior to the chemically reacting step.
However, Fontecave teaches a bicarbonate catholyte (“The concentration of the salt of hydrogen carbonate advantageously is below 10 M, for example below 1 M, notably below 0.5 M. It can be comprised between 0.01 M and 0.5 M, notably between 0.05 M and 0.2 M.” p. 19 lines 16-18) used in a bipolar membrane cell (“A H-type cell was used with the two compartments being separated by a bipolar exchange membrane” p. 27 lines 5-17) is preferably pre-heated to a temperature between 50 and 80 °C (“The cathode of the electrolysis device will be exposed to a gaseous or liquid CO2 containing composition such as a CO2-containing aqueous catholyte solution … performed at a temperature which is preferably from 10 to 100 °C, notably from 20 to 100 °C, such as from 50 to 80 °C” p. 18 lines 22-30), a range fully encompassing the claimed range, before electrochemical reduction of carbon dioxide to carbon monoxide (p. 23 line 25 – p. 24 line 5).
As Mallouk and Fontecave each teach methods for the electrochemical reduction of carbon dioxide using a bicarbonate electrolyte in a bipolar membrane cell, Mallouk and Fontecave are analogous art to the instant invention.
It would therefore have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application to modify the method of Mallouk, such that the system, in particular the catholyte, is pre-heated to a temperature in the range from about 50 °C to 80 °C, a range encompassing the claimed range, prior to the chemically reacting step, as taught by Fontecave. A person having ordinary skill in the art would have been motivated to make this modification because Fontecave teaches this temperature range is preferable. Furthermore, combining prior art elements (i.e., the catholyte pre-heating step of Fonetcave with the method of Mallouk) according to known methods to yield predictable results establishes a prima facie case of obviousness (MPEP § 2143(I)(A)). A range in the prior art encompassing a claimed range establishes a prima facie case of obviousness (MPEP § 2144.05).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Low et al. (“Enhanced Electroreduction of Carbon Dioxide to Methanol Using Zinc Dendrites Pulse-Deposited on Silver Foam” Angew. Chem. Int. Ed. 2019, 58, 2256 –2260 and SI) teaches a silver foam electrode treated to increase the electrochemically active surface area by depositing nanoparticles for CO2 reduction (relates to claims 114, 116, and 119).
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/ALEXANDER R. PARENT/Examiner, Art Unit 1795
/LUAN V VAN/Supervisory Patent Examiner, Art Unit 1795