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

By McKone, James R.; Warren, Emily L.; Bierman, Matthew J.; Boettcher, Shannon W.; Brunschwig, Bruce S.; Lewis, Nathan S. & Gray, Harry B.
Published in Energy Environ. Sci. The Royal Society of Chemistry 2011

Abstract

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 [less-than-or-equal] 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-2 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 [approximate] 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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