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 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 4 and 11 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. These claims recite the limitation of the membrane, cathode, and anode of claim 1 (applied to claim 4) or claim 9 (applied to claim 11) having the same elements. It is unclear in view of the specification if this refers to their structural compositions, such as in claims 5 and 12, wherein all claimed cell components comprise proton and electron-conducting phases, or their literal elemental composition.
For the purpose of examination on the merits, claims 4 and 11 will be interpreted as referring to the same structural elements in the membrane, anode, and cathode.
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.
Claims 1-5, 7-12, 14, 16, and 18-21 are rejected under 35 U.S.C. 103 as being unpatentable over Katikaneni et al. (US 2022/0002151 A1) in view of Hall et al. (US 2020/0255962 A1) and Farandos et al. (US 2021/0175531 A1).
Regarding claims 1, 9, 10, and 19, Katikaneni teaches a system and method for producing hydrogen comprising an electrochemical reactor with an anode and cathode (Abstract). The anode is supplied with ammonia in a first stream and the hydrogen gas product is extracted from the cathode in a second stream (Fig. 2: NH3 entering anode 102, H2- exiting cathode 106). A solid proton-conductive electrolyte separates the anode and cathode and their respective streams ([0016]; Fig. 2: 104).
Katikaneni does not teach that the anode and cathode are porous, nor that the solid electrolyte is directly comparable to a membrane, nor that it is conductive to both electrons and protons.
However, Hall teaches another electrochemical reactor for the production of hydrogen from a fuel source ([0007]). In this reactor, the anode and cathode are both porous ([0180]: cathode; [0182]: anode). The electrodes are separated by a membrane, also described as an electrolyte in some embodiments ([0101]-[0104]: membrane or electrolyte).
Furthermore, Farandos teaches “mixed conducting" membranes able to transport both protons and electrons ([0024]). These membranes may be used in hydrogen generation ([0004]), in which the fuel may be ammonia ([0007]). When such an electrolyte or membrane is used, the interconnect may be omitted from the electrochemical reactor ([0053]).
It would have been obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the electrochemical reactor disclosed by Katikaneni by using porous electrodes and an electrolyte or membrane which is conductive to both protons and electrons. One would have been motivated to make these modifications in order to improve the flow of gaseous reactants and products throughout the reactor (Farandos [0029]: porous anode), and to eliminate the need for an external power source when producing hydrogen gas from ammonia, resulting in a less energy-demanding reactor.
Regarding claim 2, Katikaneni in view of Hall and Farandos teaches that the ammonia supplied to the reactor is cracked in-situ at the anode (Katikaneni [0018]; Fig. 1: NH3 reaction shown in anode 102).
Regarding claims 3, 8, 18 and 21, Katikaneni teaches that the pressure of the anode and/or cathode may be regulated using a pump, valve, regulator, or combination thereof ([0020]). While this does not explicitly teach using a vacuum, one skilled in the art will recognize that it is within the scope of the teachings to apply a vacuum to the cathode, as this reads on pressurizing the cathode using, e.g. a pump.
Additionally, because ammonia cracking takes place in situ at the anode as previously applied to claim 2, and a membrane exists between the anode and cathode; one would expect a higher partial pressure of hydrogen in the anode compared to the cathode under normal operating conditions. The claimed subject matter is therefore obvious to one skilled in the art.
Regarding claims 4, 5, 7, 11, 12, 14, and 16, Hall teaches embodiments of the hydrogen production system having a first and second electrode each comprising Ni and YSZ, LSGM, SSZ, or combinations thereof (Hall [0123], and nickel disclosed as a conductive metal in [0131]). These electrode materials are demonstrated by Farandos to be proton-conductive (Farandos’ abstract; [0024]: ionic conductivity may refer to protons). The mixed-conducting electrolyte or membrane may also comprise a combination of Ni and YSZ, LSGM, or SSZ (Hall [0131]). These embodiments read on the composition of the anode, cathode, and membrane having the same elements, i.e. a proton-conducting and electron-conducting phase.
Regarding claim 20, Katikaneni alone does not teach the claimed operating temperature of the reactor. However, Hall and Farandos both teach that the reactor of claim 9 operates at a temperature of no less than 500 °C (Hall [0161], Farandos [0061]). It would therefore be obvious to one skilled in the art to use this minimum temperature in order to effectively produce hydrogen from ammonia fuel using the system of claim 9.
Claims 6 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Katikaneni in view of Hall and Farandos as applied to claims 1, 5, 9, and 12 above, and further in view of Eguchi et al (JP 2017050180 A, using attached machine translation).
Regarding claims 6 and 13, Katikaneni in view of Hall and Farandos teaches the inherited limitations from claims 5 and 12 on which they depend, but does not teach any proton-conducting phase composition as claimed. However, Eguchi teaches an electrode for a fuel cell which consumes ammonia to produce hydrogen, the electrode comprising a solid electrolyte conductive to protons ([0063]) and an electronically conductive metal ([0006]). The solid electrolyte may be BaZraCebY0.1Yb0.1--O3 ([0013]: A may be Ba, and M one or more metals including Y and Yb). The ranges given for coefficients a and b would not exclude x or 0.8-x as claimed. Rare-earth metal-doped barium zirconates or zirconate-cerates such as claimed are also highly conductive to protons ([0008]).
It would have been obvious for one of ordinary skill in the art to use such a proton-conducting material in the electrodes and the membrane of the claimed invention. One would have been motivated to make this modification in order to run the electrochemical reactor at a lower temperature compared to one utilizing conventional oxide ion conductors while still maintaining effective ammonia decomposition ([0007]: power generation at 400-700 °C is possible). The expected outcome of such a change would include reducing the operational costs, temperature hazards, and wear on cell components associated with high-temperature operations in the art.
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Katikaneni in view of Hall and Farandos as applied to claims 9, 12, and 14 above, and further in view of Yan et al. (US 2020/0161684 A1).
Regarding claim 15, Katikaneni in view of Hall and Farandos teaches all inherited limitations from claims 9, 12, and 14 on which it depends. These three references do not teach a lanthanum-doped strontium titanate for the electron-conducting phase comprising LaSrCaTiO-3. However, Yan teaches an electrochemical device with an anode, cathode, and anion exchange polymer between the two (Abstract). The cathode electrocatalyst may be a perovskite such as LaSrCaTiO3 ([0069]: as ABX3 where A is La, Sr, and Ca, B is Ti, and X is O). It would have been obvious to one skilled in the art to use such an LST for the electron-conducting phase of the claimed invention, because this Yan teaches that this material is also effective in hydrogen evolution ([0129]).
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Katikaneni in view of Hall and Farandos as applied to claims 9, 12, and 14 above, and further in view of Holmel et al. (US 2010/0086824 A1).
Regarding claim 17, Hall further teaches that the electron-conducting phase of the membrane may be “strontium doped lanthanum chromite, iron doped lanthanum chromite, lanthanum calcium chromite, or combinations thereof” (Hall [0009]). While Hall does not teach using these materials in the anode and/or cathode, Farandos teaches that the anode may comprise a doped lanthanum chromite (Farandos [0007]). Katikaneni, Hall, and Farandos do not teach using this material in the cathode of the claimed electrochemical reactor. However, Holmel teaches another electrochemical reactor in which both the inner and outer electrodes comprise strontium-doped lanthanum chromite (Holmel claims 1, 10, and 11). It is therefore obvious to substitute doped lanthanum chromite into the anode, cathode, and electrolyte or membrane of the claimed invention, as doped lanthanum chromite perovskites have been shown to have the desired mixed-conducting properties required by solid oxide electrolytic cells while also maintaining chemical stability in both oxidizing and reducing atmospheres (Holmel [0079]).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: Kim et al. (WO 2022245081 A1, using attached machine translation) teaches a system for producing hydrogen using an ammonia fuel cell. Majima et al. (US 2011/0177407 A1) teaches an electrochemical reactor for decomposition of ammonia.
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/CBF/Examiner, Art Unit 1711
/MICHAEL E BARR/Supervisory Patent Examiner, Art Unit 1711
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