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Decoupling H_2(g) and O_2(g) Production in Water Splitting by a Solar-Driven V^(3+/2)+(aq,H_2SO_4)|KOH(aq) Cell

Ho, Alec and Zhou, Xinghao and Han, Lihao and Sullivan, Ian and Karp, Christoph and Lewis, Nathan S. and Xiang, Chengxiang (2019) Decoupling H_2(g) and O_2(g) Production in Water Splitting by a Solar-Driven V^(3+/2)+(aq,H_2SO_4)|KOH(aq) Cell. ACS Energy Letters, 4 (4). pp. 968-976. ISSN 2380-8195. http://resolver.caltech.edu/CaltechAUTHORS:20190321-152633678

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Abstract

A solar-driven V^(3+/2+)(aq,H_2SO_4)|KOH(aq) cell, consisting of a carbon-cloth cathode in 2.0 M H_2SO_4(aq) with 0.36 M V_2(SO_4)_3 (pH −0.16), a Ni mesh anode in 2.5 M KOH(aq) (pH 14.21) for the oxygen-evolution reaction (OER), and a bipolar membrane that sustained the pH differentials between the catholyte and anolyte, enabled water splitting with spatial and temporal decoupling of the hydrogen evolution reaction (HER) from the OER and produced H_2(g) locally under pressure upon demand. Over a range of potentials and charging depths, V^(3+) was selectively reduced with >99.8% faradic efficiency. The V^(2+) species produced in the catholyte was then passed subsequently on demand over a MoCx-based HER catalyst to produce H_2(g) and regenerate V^(3+) for subsequent reduction. Under a base hydrogen pressure of 1, 10, and 100 atm, the discharge efficiency of the V^(3+) to hydrogen was 83%, 65.2%, and 59.8%, respectively. In conjunction with a solar tracker and a photovoltaic device, the V^(3+/2+)(aq,H_2SO_4)|KOH(aq) cell was charged outdoors under sunlight and discharged at night with a daily averaged diurnal solar-to-hydrogen (STH) energy conversion efficiency of 3.7% and a STH conversion efficiency of 5.8% during daylight operation.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acsenergylett.9b00278DOIArticle
https://pubs.acs.org/doi/suppl/10.1021/acsenergylett.9b00278PublisherSupporting Information
ORCID:
AuthorORCID
Zhou, Xinghao0000-0001-9229-7670
Han, Lihao0000-0002-0452-3381
Lewis, Nathan S.0000-0001-5245-0538
Xiang, Chengxiang0000-0002-1698-6754
Alternate Title:Decoupling H2(g) and O2(g) Production in Water Splitting by a Solar-Driven V3+/2+(aq,H2SO4)|KOH(aq) Cell
Additional Information:© 2019 American Chemical Society. Received: February 4, 2019; Accepted: March 21, 2019; Published: March 21, 2019. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993, as well as the Gordon and Betty Moore Foundation. The authors thank Caltech’s SURF Board for a Summer Undergraduate Research Fellowship and acknowledge Caltech’s Federal Work-Study program. The authors declare no competing financial interest.
Group:JCAP, Kavli Nanoscience Institute
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0004993
Gordon and Betty Moore FoundationUNSPECIFIED
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Record Number:CaltechAUTHORS:20190321-152633678
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20190321-152633678
Official Citation:Decoupling H2(g) and O2(g) Production in Water Splitting by a Solar-Driven V3+/2+(aq,H2SO4)|KOH(aq) Cell. Alec Ho, Xinghao Zhou, Lihao Han, Ian Sullivan, Christoph Karp, Nathan S. Lewis, and Chengxiang Xiang. ACS Energy Letters 2019 4 (4), 968-976. DOI: 10.1021/acsenergylett.9b00278
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94034
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:21 Mar 2019 23:26
Last Modified:17 Apr 2019 21:52

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