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
Applicant’s election without traverse of Group I, claims 1-2, 4-6, 10, 12-14, and 19, in the reply filed on 26 June 2026 is acknowledged.
Claims 20-25 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to nonelected inventions, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 26 June 2026.
Information Disclosure Statements
The Information Disclosure Statements filed on 27 December 2023, 23 January 2026, and 7 July 2026 have been received and considered by the Examiner.
Claim Interpretation
The term “normal pressure” in claim 1 is interpreted as meaning about atmospheric pressure or without reducing the pressure.
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.
Claims 1, 4-5, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Qi et al. (Adv. Mater. Res. 2011, 306-307, 234-237; NPL Document #1 on the IDS filed 27 December 2023) in view of Gao et al. (J. Chin. Ceram. Soc. 2011, 39, 1423-1427), Baker et al. (Inorg. Synth. 1950, 3, 117-118) and Ning et al. (CN 1899970 A). The provided English machine translations of Gao (J. Chin. Ceram. Soc. 2011, 39, 1423-1427) and Ning (CN 1899970 A) are relied upon in the analysis below.
Regarding claim 1, Qi discloses a method for preparing vanadium dioxide powder comprising: heating ammonium vanadate (NH4VO3) powder at 727 °C (1000 K) in an electric furnace (tube furnace) under normal pressure in a nitrogen atmosphere and maintaining the heating temperature for 1.5 hours to partially reduce the ammonium vanadate (NH4VO3) powder to vanadium dioxide (VO2) powder and cooling the reduced vanadium dioxide (VO2) powder to 227° C (500 K) in the electric furnace in a nitrogen atmosphere (p. 235, ¶ 1).
Qi alternatively teaches that VO2 powder can be prepared by partially reducing vanadium pentoxide in an ammonia atmosphere (p. 235, ¶ 1).
Regarding the temperature at which the ammonium vanadate is heated, it is noted that Qi teaches heating to 727 °C, which lies just outside the claimed range of 560 °C to 720 °C.
The courts have stated where the claimed ranges “overlap or lie inside the ranges disclosed by the prior art” and even when the claimed ranges and prior art ranges do not overlap but are close enough that one skilled in the art would have expected them to have similar properties, a prima facie case of obviousness exists (see In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); Titanium Metals Corp. of America v. Banner, 778 F2d 775. 227 USPQ 773 (Fed. Cir. 1985) (see MPEP 2144.05.01). One of ordinary skill in the art would not expect a difference in results between heating at 720 °C and heating at 727 °C. Therefore, the claimed range of temperature merely represents an obvious variant and/or routine optimization of the values of the cited prior art.
Qi does not teach leaching vanadium pentoxide (V2O5) powder with an aqueous alkaline salt solution of NaOH or KOH, followed by separation and filtration, and reaction with an ammonia solution to prepare ammonium vanadate (NH4VO3) powder, nor does Qi teaching cooling all the way to 50 °C to 120 °C in an electric furnace or horizontal furnace under nitrogen or argon atmosphere, as required by the instant claim.
However, Gao teaches a method for preparing ammonium vanadate (ammonium metavanadate, NH4VO3) in which vanadium pentoxide is treated with an alkaline salt solution of NaOH and reaction with ammonia solution to prepare ammonium vanadate powder (Section 1.1).
Gao does not teach separation and filtration of the intermediate sodium vanadate before reaction with an ammonia solution.
However, Baker also teaches the preparation of ammonium vanadate by treating V2O5 with an alkaline solution (sodium carbonate), and further teaches the separation and filtration to remove residues before adding a source of ammonia (p. 119, ¶ 2).
Regarding the V2O5 being a powder, while neither Gao nor Baker explicitly teach the vanadium oxide being a powder, vanadium oxide is inherently a solid and the choice of a powdered form would have been obvious to one of ordinary skill in the art because it is well known that powders have large surface areas and therefore dissolve faster and have higher reaction rates than the corresponding non-powder, crystalline forms.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to prepare the ammonium vanadate used in the method of Qi by leaching vanadium pentoxide (V2O5) powder with an aqueous alkaline salt solution of NaOH, followed by separation and filtration, and reaction with an ammonia solution to prepare ammonium vanadate (NH4VO3) powder, as taught by Gao and Baker. One of ordinary skill in the art would have been motivated to do so because they would simply be combining known methods of preparing ammonium vanadate with a method that calls for using ammonium vanadate to yield predictable results.
Additionally, Ning also teaches the production of vanadium dioxide powders via a pyrolysis method ([0013]-[0014]). Ning further teaches that their particles are of high purity (title), and that the final step of the reaction is cooling to below 100 °C while under a protective atmosphere (the reaction product is cooled to below 100°C in the presence of a protective gas… to obtain pure-phase blue-black vanadium dioxide ultrafine powder; [0014]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the method of Qi such that in the cooling step the powder is allowed to cool to below 100 °C, as taught by Ning, which overlaps with the claimed range of cooling to 50 °C to 120 °C. One of ordinary skill in the art would have been motivated to do so because Ning teaches that cooling to these temperatures under protective gas is appropriate in a method that yields high purity vanadium dioxide powder.
It is again noted that the courts have stated where the claimed ranges “overlap or lie inside the ranges disclosed by the prior art” a prima facie case of obviousness exists. Therefore, the claimed range of 50 °C to 120 °C merely represents an obvious variant and/or routine optimization of the teaching of less than 100 °C in the cited prior art.
Regarding claim 4, modified Qi teaches the method of claim 1, where Gao teaches the leaching is performed with heating until the solid is completely dissolved (Section 1.1.1). Gao does not explicitly teach the temperature or duration of the reaction being within the claimed range.
However, Gao’s teaching to heat an aqueous solution can be considered to teach a temperature somewhere in the range of just above room temperature up to the boiling point of the solution, or ~25 °C to ~100 °C, which overlaps with the instantly claimed range of 20-80°C.
It is noted that the courts have stated where the claimed ranges “overlap or lie inside the ranges disclosed by the prior art” a prima facie case of obviousness exists, and that, generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. (see In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990); Titanium Metals Corp. of America v. Banner, 778 F2d 775. 227 USPQ 773 (Fed. Cir. 1985) (see MPEP 2144.05.01). In the instant case there is nothing to suggest that the claimed temperature range is critical. Therefore, the claimed ranges merely represent an obvious variant and/or routine optimization of the values of the cited prior art.
Regarding the time of reaction, it is well known to persons of ordinary skill in the art that the time of process steps in chemical processes affect the completion of the chemical reaction and the yield of products. Absent new and unexpected results, it would have been prima facie obvious to one of ordinary skill in the art at the time of the invention to vary the reaction time by routine experimentation in order to an optimum or workable range during which the reaction can reach the desired degree of completion.
Regarding claim 5, modified Qi teaches the method of claim 1, where Gao also teaches, following addition of ammonia, a reaction temperature of 50 °C (Section 1.1 and 2.1.4) and that the reaction reaches completion at about 450 minutes (Fig. 5), each of which lie in the instantly claimed ranges.
Regarding claim 10, modified Qi teaches the method of claim 1, where Ning teaches that after cooling to below 100 °C under protective atmosphere the vanadium dioxide powder can be removed to the air ([0014]), where it will cool further to ambient temperature.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to cool the reduced vanadium dioxide powder in the air after cooling the powder in an electric furnace, as taught by Ning. One of ordinary skill in the art would have been motivated to do so because Ning teaches that these conditions are suitable for generating high purity powder, and handling under air at ambient temperature is operationally simpler than unnecessarily keeping it warm under a protective atmosphere.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Qi et al. (Adv. Mater. Res. 2011, 306-307, 234-237; NPL Document #1 on the IDS filed 27 December 2023) in view of Gao et al. (J. Chin. Ceram. Soc. 2011, 39, 1423-1427), Baker et al. (Inorg. Synth. 1950, 3, 117-118) and Ning et al. (CN 1899970 A), as applied to claim 1, and further in view of Dong (“Inventory of commonly used ceramic crucibles in laboratories”, Retrieved from the Internet: <URL: https://www.linkedin.com/pulse/inventory-commonly-used-ceramic-crucibles-yuli-dong>, Retrieved 18 August 2026, published 13 May 2020). The provided English machine translations of Gao (J. Chin. Ceram. Soc. 2011, 39, 1423-1427) and Ning (CN 1899970 A) are relied upon in the analysis below.
Regarding claim 6, modified Qi teaches the method of claim 1, where Qi teaches the ammonia vanadate powder being charged into a ceramic container and heated in an electric furnace (tube furnace) under normal pressure in a nitrogen atmosphere.
Qi does not explicitly teach that the ceramic container is an alumina crucible.
However, Dong teaches that alumina crucibles are among the most common ceramic crucibles and that they are suitable at the temperatures used in the method of Qi, and that they have good mechanical stability (Section 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use as the ceramic container in the method of Qi an alumina crucible, as taught by Dong. One of ordinary skill in the art would have been motivated to do so because while Qi is silent on the precise composition required, Dong teaches that alumina crucibles are largely suitable for the chemical conditions and temperatures used in the method of Qi, and Dong further teaches that they have good mechanical stability.
Claims 2, 12-13 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Qi et al. (Adv. Mater. Res. 2011, 306-307, 234-237; NPL Document #1 on the IDS filed 27 December 2023) in view of Zou et al. (CN 102795668 A), Gao et al. (J. Chin. Ceram. Soc. 2011, 39, 1423-1427), Baker et al. (Inorg. Synth. 1950, 3, 117-118) and Feng (CN 101372321 A). The provided English machine translations of Zou (CN 102795668 A), Gao (J. Chin. Ceram. Soc. 2011, 39, 1423-1427), and Feng (CN 101372321 A) are relied upon in the analysis below.
Regarding claim 2, Qi discloses a method for preparing vanadium dioxide powder comprising: heating ammonium vanadate (NH4VO3) powder at 727 °C (1000 K) in an electric furnace (tube furnace) in a nitrogen atmosphere and maintaining the heating temperature for 1.5 hours to partially reduce the ammonium vanadate (NH4VO3) powder to vanadium dioxide (VO2) powder and cooling the reduced vanadium dioxide (VO2) powder to 227° C (500 K) in the electric furnace in a nitrogen atmosphere (p. 235, ¶ 1).
Qi alternatively teaches that VO2 powder can be prepared by partially reducing vanadium pentoxide in an ammonia atmosphere (p. 235, ¶ 1).
Qi does not teach leaching vanadium pentoxide (V2O5) powder with an aqueous alkaline salt solution of NaOH or KOH, followed by separation and filtration, and reaction with an ammonia solution to prepare ammonium vanadate (NH4VO3) powder. Qi also does not teach heating the ammonium vanadate powder at 300 to 480 °C in a vacuum induction furnace under reduced pressure. Nor does Qi teaching cooling all the way to 50 °C to 120 °C in a vacuum induction furnace, as required by the instant claim.
However, Gao teaches a method for preparing ammonium vanadate (ammonium metavanadate) in which vanadium pentoxide is treated with an alkaline salt solution of NaOH and reaction with ammonia solution to prepare ammonium vanadate powder (Section 1.1).
Gao does not teach separation and filtration of the intermediate sodium vanadate before reaction with an ammonia solution.
However, Baker also teaches the preparation of ammonium vanadate by treating V2O5 with an alkaline solution (sodium carbonate), and further teaches the separation and filtration to remove residues before adding a source of ammonia (p. 119, ¶ 2).
Regarding the V2O5 being a powder, while neither Gao nor Baker explicitly teach the vanadium oxide being a powder, vanadium oxide is inherently a solid and the choice of a powdered form would have been obvious to one of ordinary skill in the art because it is well known that powders have large surface areas and therefore dissolve faster and have higher reaction rates than the corresponding non-powder, crystalline forms.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to prepare the ammonium vanadate used in the method of Qi by leaching vanadium pentoxide (V2O5) powder with an aqueous alkaline salt solution of NaOH, followed by separation and filtration, and reaction with an ammonia solution to prepare ammonium vanadate (NH4VO3) powder, as taught by Gao and Baker. One of ordinary skill in the art would have been motivated to do so because they would simply be combining known methods of preparing ammonium vanadate with a method that calls for using ammonium vanadate to yield predictable results.
Furthermore, Zou also teaches a method of preparing VO2 powders by the thermolysis of ammonium vanadates and Zou further teaches that these reactions can be performed at 400-900 °C and under vacuum or in an inert gas environment ([0009]). It is noted that while Zou performs a pre-treatment of ammonium metavanadate (ammonium vanadate, NH4VO3) with a reductant, such as fructose in Example 2 ([0035]), Qi demonstrates that such a reductant may not be necessary.
Regarding the precise pressure in the furnace, while Zou does not explicitly disclose a pressure, they do teach that vacuum condition or an N2 atmosphere represent possible inert gas environments. This can be interpreted as encompassing 0-1 atm of nitrogen, which overlaps with the instantly claimed conditions.
Zou also teaches that the vanadium dioxide powder is cooled below 100 °C with the furnace.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Qi to heat the ammonium vanadate powder to a temperature anywhere in the range of 400 °C to 900 °C, which overlaps with the claimed range of 320 °C to 480 °C, in a furnace under reduced pressure in a nitrogen atmosphere, as taught by Zou. It would have been further obvious to also modify the method of Qi such that in the cooling step the powder is allowed to cool to below 100 °C in the furnace, as also taught by Zou, which overlaps with the claimed range of cooling to 50 °C to 120 °C.
It is again noted that the courts have stated where the claimed ranges “overlap or lie inside the ranges disclosed by the prior art” a prima facie case of obviousness exists, and that generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such pressure, a measure of gas concentration, or temperature is critical. Therefore, the claimed ranges of pressure in the heating step and temperatures in both the heating and cooling step merely represent obvious variants and/or routine optimizations of the teaching of the values in the cited prior art.
Regarding the heating using a vacuum induction furnace, Qi and Zou each use a tube furnace, where Zou teaches use of a vacuum tube furnace to achieve reduced pressure conditions (placed in a tube furnace, evacuated; [0034]), and not a vacuum induction furnace. However, Feng also teaches the reduction of vanadium oxides under high temperature conditions ([0028], [0029] and [0033]), and further teaches that an induction furnace can provide good heating of raw materials including ammonium vanadate (ammonium metavanadate; [0029]-[0030]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to replace the vacuum tube furnace in the method of modified Qi with a vacuum induction furnace, as taught by Feng, thereby arriving at the invention of the instant claim. One of ordinary skill in the art would have been motivated to do so because Feng teaches that an induction furnace can provide good heating of the ammonium vanadate materials that is used in the method of Qi.
Regarding claim 12, modified Qi teaches the method of claim 12, where Gao teaches the leaching is performed with heating until the solid is completely dissolved (Section 1.1.1). Gao does not explicitly teach the temperature or duration of the reaction being within the claimed range.
However, Gao’s teaching to heat an aqueous solution can be considered to teach a temperature somewhere in the range of just above room temperature up to the boiling point of the solution, or ~25 °C to ~100 °C, which overlaps with the instantly claimed range of 20-80°C.
It is again noted that the courts have stated where the claimed ranges overlap or lie inside the ranges disclosed by the prior art a prima facie case of obviousness exists, and that, generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. In the instant case there is nothing to suggest that the claimed range is critical. Therefore, the claimed ranges merely represent an obvious variant and/or routine optimization of the values of the cited prior art.
Regarding the time of reaction, it is well known to persons of ordinary skill in the art that the time of process steps in chemical processes affect the completion of the chemical reaction and the yield of products. Absent new and unexpected results, it would have been prima facie obvious to one of ordinary skill in the art at the time of the invention to vary the reaction time by routine experimentation in order to an optimum or workable range during which the reaction can reach the desired degree of completion.
Regarding claim 13, modified Qi teaches the method of claim 2, where Gao also teaches, following addition of ammonia, a reaction temperature of 50 °C (Section 1.1 and 2.1.4) and that the reaction reaches completion at about 450 minutes (Fig. 5), each of which lie in the instantly claimed ranges.
Regarding claim 19, modified Qi teaches the method of claim 2, where Zou teaches cooling to below 100 °C in the furnace powder, after which time the sample is removed to the air (the sample is taken out; [0034]), where it will cool further to ambient temperature.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to cool the reduced vanadium dioxide powder in the air after cooling the powder in the furnace, as taught by Zou. One of ordinary skill in the art would have been motivated to do so because Zou teaches that these conditions are suitable for generating the desired vanadium dioxide powder, and handling under air at ambient temperature is operationally simpler than unnecessarily keeping it warm under a protective atmosphere.
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Qi et al. (Adv. Mater. Res. 2011, 306-307, 234-237; NPL Document #1 on the IDS filed 27 December 2023) in view of Zou et al. (CN 102795668 A), Gao et al. (J. Chin. Ceram. Soc. 2011, 39, 1423-1427), Baker et al. (Inorg. Synth. 1950, 3, 117-118) and Feng (CN 101372321 A), as applied to claim 2, and further in view of Dong (“Inventory of commonly used ceramic crucibles in laboratories”, Retrieved from the Internet: <URL: https://www.linkedin.com/pulse/inventory-commonly-used-ceramic-crucibles-yuli-dong>, Retrieved 18 August 2026, published 13 May 2020). The provided English machine translations of Zou (CN 102795668 A), Gao (J. Chin. Ceram. Soc. 2011, 39, 1423-1427), and Feng (CN 101372321 A) are relied upon in the analysis below.
Regarding claim 14, modified Qi teaches the method of claim 2, where Qi teaches the ammonia vanadate powder being charged into a ceramic container and heated in an electric furnace (tube furnace) under normal pressure in a nitrogen atmosphere.
Qi does not explicitly teach that the ceramic container is an alumina crucible.
However, Dong teaches that alumina crucibles are among the most common ceramic crucibles and that they are suitable at the temperatures used in the method of Qi, and that they have good mechanical stability (Section 1).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use as the ceramic container in the method of Qi an alumina crucible, as taught by Dong. One of ordinary skill in the art would have been motivated to do so because while Qi is silent on the precise composition required, Dong teaches that alumina crucibles are largely suitable for the chemical conditions and temperatures used in the method of Qi, and Dong further teaches that they have good mechanical stability.
Pertinent Prior Art
The following prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
US 2017/0121229 A1 describes the thermolytic reduction of ammonium vanadate to vanadium dioxide at temperatures of 600-800 °C for 2-4 hours, and that various level of nitrogen content can be achieved by varying time, temperature, and atmosphere.
Zhang et al. (Journal of Solid State Chemistry 2022, 311, 123117) describe the fabrication of VO2 by thermolysis of ammonium metavanadate under sealed conditions. The publication date of this document is after the effective filing date of the foreign priority document, but no translation of the certified priority document has been provided. See MPEP §§ 215 and 216.
Conclusion
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.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Sally Merkling can be reached at (571) 272-6297. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/NICHOLAS A. PIRO/Assistant Examiner, Art Unit 1738
/PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735
Prosecution Insights