p-Si/W2C and p-Si/W2C/Pt Photocathodes for the Hydrogen Evolution Reaction

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• 作者：Sean P. Berglund ; Huichao He ; William D. Chemelewski ; Hugo Celio ; Andrei Dolocan ; C. Buddie Mullins
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：January 29, 2014
• 年：2014
• 卷：136
• 期：4
• 页码：1535-1544
• 全文大小：699K
• ISSN：1520-5126

文摘

p-Si/W₂C photocathodes are synthesized by evaporating tungsten metal in an ambient of ethylene gas to form tungsten semicarbide (W₂C) thin films on top of p-type silicon (p-Si) substrates. As deposited the thin films contain crystalline W₂C with a bulk W:C atomic ratio of approximately 2:1. The W₂C films demonstrate catalytic activity for the hydrogen evolution reaction (HER), and p-Si/W₂C photocathodes produce cathodic photocurrent at potentials more positive than 0.0 V vs RHE while bare p-Si photocathodes do not. The W₂C films are an effective support for Pt nanoparticles allowing for a considerable reduction in Pt loading. p-Si/W₂C/Pt photocathodes with Pt nanoparticles achieve photocurrent onset potentials and limiting photocurrent densities that are comparable to p-Si/Pt photocathodes with Pt loading nine times higher. This makes W₂C an earth abundant alternative to pure Pt for use as an electrocatalyst on photocathodes for the HER.