Photoelectrochemical Hydrogen Evolution Using Si Microwire Arrays

Boettcher, Shannon W.; Warren, Emily L.; Putnam, Morgan C.; Santori, Elizabeth A.; Turner-Evans, Daniel B.; Kelzenberg, Michael D.; Walter, Michael G.; McKone, James R.; Brunschwig, Bruce S.; Atwater, Harry A.; Lewis, Nathan S.

doi:10.1021/ja108801m

Cited by 578 publications

(661 citation statements)

References 29 publications

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“…This combined behavior thus produced similar performance to the best-performing microwire-array photocathodes that have been reported previously. 6,7,25 Integration of the Ni-Mo and TiO 2 layers, to form the complete MEA device depicted in Fig. 2, resulted in Z IRC = 2.9% for the bestperforming Si microwire photocathodes in conjunction with the earth-abundant electrocatalysts that were prepared in this work.…”

Section: Photoelectrode Resultsmentioning

confidence: 91%

Functional integration of Ni–Mo electrocatalysts with Si microwire array photocathodes to simultaneously achieve high fill factors and light-limited photocurrent densities for solar-driven hydrogen evolution

Shaner

McKone

Gray

et al. 2015

Energy Environ. Sci.

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An n + p-Si microwire array coupled with a two-layer catalyst film consisting of Ni-Mo nanopowder and TiO 2 light-scattering nanoparticles has been used to simultaneously achieve high fill factors and lightlimited photocurrent densities from photocathodes that produce H 2 (g) directly from sunlight and water.The TiO 2 layer scattered light back into the Si microwire array, while optically obscuring the underlying Ni-Mo catalyst film. In turn, the Ni-Mo film had a mass loading sufficient to produce high catalytic activity, on a geometric area basis, for the hydrogen-evolution reaction. The best-performing microwire array devices prepared in this work exhibited short-circuit photocurrent densities of À14.3 mA cm À2 , photovoltages of 420 mV, and a fill factor of 0.48 under 1 Sun of simulated solar illumination, whereas the equivalent planar Ni-Mo-coated Si device, without TiO 2 scatterers, exhibited negligible photocurrent due to complete light blocking by the Ni-Mo catalyst layer. Broader contextSolar-driven photoelectrochemical water splitting is a promising approach to enable the large-scale conversion and storage of solar energy. Few integrated systems have been realized that use earth-abundant semiconductor and catalyst materials for the half-reactions involved in solar-driven water-splitting, i.e. hydrogen evolution and oxygen evolution, while also achieving high energy-conversion efficiencies. We describe herein a hydrogen-evolving Si-based photoelectrode that exhibits high light-limited photocurrent densities, as well as high catalytic activities, while using a high mass loading of an earth-abundant electrocatalyst. The design is reminiscent of a membrane-electrode assembly as used for stand-alone fuel cell and electrolysis systems. The approach exploits the high aspect ratio of the absorber layer to avoid parasitic optical absorption normally associated with a thick catalyst layer on the surface of an illuminated photocathode.

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Section: Photoelectrode Resultsmentioning

confidence: 91%

Functional integration of Ni–Mo electrocatalysts with Si microwire array photocathodes to simultaneously achieve high fill factors and light-limited photocurrent densities for solar-driven hydrogen evolution

Shaner

McKone

Gray

et al. 2015

Energy Environ. Sci.

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“…These J sc values are close to the values that have been reported for p-Si microwire arrays in contact with MV 2+/+ (aq), as well as for HER using a Pt electrocatalyst, suggesting minimal net absorption or reflection by the catalyst particles. 12,25 4. Overall photoelectrode performance.…”

Section: Photoelectrochemical Behavior Of Electrocatalysts On P-simentioning

confidence: 99%

“…11 Radial n + -p junction Si microwire array photocathodes that have been decorated with islands of Pt as an electrocatalyst have yielded, with only $50% light absorption, >5% thermodynamically based energy conversion efficiencies for the production of H 2 (g) from 0.5 M H 2 SO 4 (aq) under simulated AM1.5 illumination. 12 A goal is therefore to use earth-abundant electrocatalysts to achieve performance for H 2 (g) evolution that is comparable to that obtainable using Pt or Pd as electrocatalysts.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Pt, Ni, and Ni–Mo electrocatalysts for hydrogen evolution on crystalline Si electrodes

McKone

Warren

Bierman

et al. 2011

Energy Environ. Sci.

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452

382

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The dark electrocatalytic and light photocathodic hydrogen evolution properties of Ni, Ni-Mo alloys, and Pt on Si electrodes have been measured, to assess the viability of earth-abundant electrocatalysts for integrated, semiconductor coupled fuel formation. In the dark, the activities of these catalysts deposited on degenerately doped p + -Si electrodes increased in the order Ni < Ni-Mo # Pt. Ni-Mo deposited on degenerately doped Si microwires exhibited activity that was very similar to that of Pt deposited by metal evaporation on planar Si electrodes. Under 100 mW cm À2 of Air Mass 1.5 solar simulation, the energy conversion efficiencies of p-type Si/catalyst photoelectrodes ranged from 0.2-1%, and increased in the order Ni z Ni-Mo < Pt, due to somewhat lower photovoltages and photocurrents for p-Si/Ni-Mo relative to p-Si/Ni and p-Si/Pt photoelectrodes. Deposition of the catalysts onto microwire arrays resulted in higher apparent catalytic activities and similar photoelectrode efficiencies than were observed on planar p-Si photocathodes, despite lower light absorption by p-Si in the microwire structures.

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“…Constructing such a PEC cell requires both a photoanode and photocathode with high activity for water oxidation and reduction. Although many highly active and stable p-type photocathodes have been developed in recent years [8][9][10][11][12] , the more challenging task is to develop a photoanode that can stably oxidize water into oxygen under sunlight with high efficiency. The poor stability because of the strong oxidizing conditions and the low efficiency because of the high overpotential of four-electron water oxidation are the major challenges in designing the photoanode.…”

mentioning

confidence: 99%

Cobalt phosphate-modified barium-doped tantalum nitride nanorod photoanode with 1.5% solar energy conversion efficiency

et al. 2013

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Spurred by the decreased availability of fossil fuels and global warming, the idea of converting solar energy into clean fuels has been widely recognized. Hydrogen produced by photoelectrochemical water splitting using sunlight could provide a carbon dioxide lean fuel as an alternative to fossil fuels. A major challenge in photoelectrochemical water splitting is to develop an efficient photoanode that can stably oxidize water into oxygen. Here we report an efficient and stable photoanode that couples an active barium-doped tantalum nitride nanostructure with a stable cobalt phosphate co-catalyst. The effect of barium doping on the photoelectrochemical activity of the photoanode is investigated. The photoanode yields a maximum solar energy conversion efficiency of 1.5%, which is more than three times higher than that of state-of-the-art single-photon photoanodes. Further, stoichiometric oxygen and hydrogen are stably produced on the photoanode and the counter electrode with Faraday efficiency of almost unity for 100 min.

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Photoelectrochemical Hydrogen Evolution Using Si Microwire Arrays

Cited by 578 publications

References 29 publications

Functional integration of Ni–Mo electrocatalysts with Si microwire array photocathodes to simultaneously achieve high fill factors and light-limited photocurrent densities for solar-driven hydrogen evolution

Functional integration of Ni–Mo electrocatalysts with Si microwire array photocathodes to simultaneously achieve high fill factors and light-limited photocurrent densities for solar-driven hydrogen evolution

Evaluation of Pt, Ni, and Ni–Mo electrocatalysts for hydrogen evolution on crystalline Si electrodes

Cobalt phosphate-modified barium-doped tantalum nitride nanorod photoanode with 1.5% solar energy conversion efficiency

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