Prosecution Insights
Last updated: April 19, 2026
Application No. 18/034,217

WATER SPLITTING DEVICE PROTECTION

Non-Final OA §103§112
Filed
Apr 27, 2023
Examiner
CHUNG, HOSUNG CHARLES
Art Unit
1794
Tech Center
1700 — Chemical & Materials Engineering
Assignee
The Regents of the University of Michigan
OA Round
1 (Non-Final)
59%
Grant Probability
Moderate
1-2
OA Rounds
2y 10m
To Grant
97%
With Interview

Examiner Intelligence

Grants 59% of resolved cases
59%
Career Allow Rate
277 granted / 470 resolved
-6.1% vs TC avg
Strong +38% interview lift
Without
With
+38.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
26 currently pending
Career history
496
Total Applications
across all art units

Statute-Specific Performance

§101
1.1%
-38.9% vs TC avg
§103
53.0%
+13.0% vs TC avg
§102
9.8%
-30.2% vs TC avg
§112
30.1%
-9.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 470 resolved cases

Office Action

§103 §112
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. Election/Restrictions Applicant’s election without traverse of group I, claims 1-11 in the reply filed on 2/24/2026 is acknowledged. Claim s 12-29 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), there being no allowable generic or linking claim. Election was made without traverse. Claim Rejections - 35 U.S.C. § 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. Claim s 2-3 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, or for pre-AIA the applicant regards as the invention. 2-3. T he term " about " is a relative term which renders the claim indefinite. This term is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. MPEP § 2173.05(b) . Claim Rejections - 35 U.S.C. § 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 of this title, 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. Claim s 1-7 and 9-11 are rejected under 35 U.S.C. § 103 as being unpatentable over Mi et al., U.S. Patent App. Pub. No. 2016/0273115 A1 [hereinafter Mi] in view of Wang et al., A Single-Junction Cathodic Approach for Stable Unassisted Solar Water Splitting , 3 Joule 2444 (Oct. 16, 2019) [hereinafter Wang] and Kim et al., Enhanced photoelectrochemical stability of GaN photoelectrodes by Al2O3 surface passivation layer , 27(4) Optics Express A206 (2019) [hereinafter Kim] . The body of the claim is generally written with parentheses following the limitations indicating the prior art’s teachings and/or examiner notes. 1. The following references render this claim obvious. I. Mi A device (photocathode; Mi [0077], fig. 1A) comprising: a substrate having a surface (n + /p/p + Si solar cell wafer ; id. ); an array of conductive projections supported by the substrate and extending outward from the surface of the substrate (nanowire arrays; id. ) … . II. Catalyst Nanoparticles - Wang Mi’s fig. 1A embodiment is silent on a plurality of catalyst nanoparticles disposed over the array of conductive projections . However, Wang teaches <10 nm Pt nanoparticles further accelerate the water reduction reaction. Wang p. 2448, figs. 2A, 3D-G. Therefore, it would have been obvious with a reasonable expectation of success to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the aforementioned prior art’s device with Wang’s <10 nm Pt nanoparticles to further accelerate the water reduction reaction. III. Oxide Layer - Kim Mi is silent on an oxide layer covering the plurality of catalyst nanoparticles and the array of conductive projections; wherein the oxide layer has a thickness on the order of a size of each catalyst nanoparticle of the plurality of catalyst nanoparticles. However, Kim teaches an aluminum oxide thin film with thicknesses of 1 and 2 nm enhances stability and hydrogen production. Kim abstract, A207-A208. Therefore, it would have been obvious with a reasonable expectation of success to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the aforementioned prior art’s device with Kim’s aluminum oxide thin film with thicknesses of 1 or 2 nm to enhances stability and /or hydrogen production. 2. The device of claim 1, wherein the thickness of the oxide layer falls within a range of about 1 nm to about 2 nm (rejected for similar reasons stated in the claim 1 rejection) . 3. The device of claim 1, wherein the size of each catalyst nanoparticle of the plurality of catalyst nanoparticles falls in a range from about 2 nm to about 3 nm (rejected for similar reasons stated in the claim 1 rejection) . 4. The device of claim 1, wherein the oxide layer comprises aluminum oxide (rejected for similar reasons stated in the claim 1 rejection) . 5. The device of claim 1, wherein the oxide layer conformally covers the plurality of catalyst nanoparticles and the array of conductive projections (Kim teaches a conformal layer, which when applied would conformally cover) . See Kim fig. 1. 6. The device of claim 1, wherein: each conductive projection of the array of conductive projections comprises a plurality of indium gallium nitride ( InGaN ) segments; the plurality of InGaN segments comprises a first segment having a compound semiconductor composition configured for photogeneration of charge carriers (top p- InGaN segment; Mi [0077], fig. 1A) , and second and third segments configured to establish a tunnel junction (p ++ InGaN / InGaN /n ++ GaN tunnel junction; id. ) ; the substrate comprises a plurality of silicon layers; and the plurality of silicon layers are doped to establish a junction for charge carriers photogenerated in the substrate (plurality of doped silicon layers; id. ) . 7. The device of claim 6, wherein the plurality of … segments further comprises a fourth segment between the tunnel junction and the substrate (fourth segment; id. ) . Mi is silent on the fourth segment comprising InGaN . However, Wang teaches that InGaN is a suitable material for the fourth segment. Wang fig. 2A. Therefore, it would have been obvious with a reasonable expectation of success to a person having ordinary skill in the art before the effective filing date of the claimed invention to have substituted the aforementioned prior art’s material to be InGaN to yield the predictable result of having a suitable fourth segment material. 9. The device of claim 1, wherein each conductive projection of the array of conductive projections comprises indium gallium nitride doped with magnesium (magnesium doping) . Mi [0119]. 10. The device of claim 1, wherein each conductive projection of the array of conductive projections comprises a nanowire (rejected for similar reasons stated in the claim 1 rejection) . 11. The device of claim 1, wherein each catalyst nanoparticle of the plurality of catalyst nanoparticles comprises platinum (rejected for similar reasons stated in the claim 1 rejection) . Claim 8 is rejected under 35 U.S.C. § 103 as being unpatentable over Mi in view of Wang and Kim as applied to claim 1 previously, and further in view of Kibria et al., Atomic- Scale Origin of Long-Term Stability and High Performance of p- GaN Nanowire Arrays for Photocatalytic Overall Pure Water Splitting , 28 Advanced Materials 8388 (2016) [hereinafter Kibria]. 8. The device of claim 1, wherein: each conductive projection of the array of conductive projections has a semiconductor composition (semiconductor composition; Mi fig. 1A) … . Mi is silent on the semiconductor composition of each conductive projection of the array of conductive projections is terminated with nitrogen along surfaces of the conductive projection. However, Kibria teaches N termination along surfaces passivate nanowires against attack by electrolytes and is essential to efficiently separate and transport photogenerated charges. Kibria p. 8389, fig. 1. Therefore, it would have been obvious with a reasonable expectation of success to a person having ordinary skill in the art before the effective filing date of the claimed invention to have modified the aforementioned prior art’s photoelectrode with N termination along surfaces to passivate nanowires against attack by electrolytes an d/or to efficiently separate and transport photogenerated charges. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to FILLIN "Examiner name" \* MERGEFORMAT Hosung Chung whose telephone number is FILLIN "Phone number" \* MERGEFORMAT (571) 270-7578 . The examiner can normally be reached FILLIN "Work Schedule?" \* MERGEFORMAT Monday-Wednesday, 9 AM - 6 PM CT . If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, FILLIN "SPE Name?" \* MERGEFORMAT James Lin can be reached on FILLIN "SPE Phone?" \* MERGEFORMAT (571) 272-8902 . 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. /HOSUNG CHUNG/ Primary Examiner, Art Unit 1794
Read full office action

Prosecution Timeline

Apr 27, 2023
Application Filed
Mar 20, 2026
Non-Final Rejection — §103, §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

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2y 5m to grant Granted Apr 07, 2026
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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
59%
Grant Probability
97%
With Interview (+38.2%)
2y 10m
Median Time to Grant
Low
PTA Risk
Based on 470 resolved cases by this examiner. Grant probability derived from career allow rate.

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