Stable Solar-Driven Water Oxidation to O2(g) by Ni-Oxide-Coated Silicon Photoanodes.
Stable Solar-Driven Water Oxidation to O2(g) by Ni-Oxide-Coated Silicon Photoanodes.
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DOI：
10.1021/jz5026195
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发表时间：
2015-01
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通讯作者：
K. Sun;M. McDowell;A. Nielander;Shu Hu;Matthew Shaner;Fan Yang;B. Brunschwig;N. Lewis
中科院分区：
文献类型：
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作者：
K. Sun;M. McDowell;A. Nielander;Shu Hu;Matthew Shaner;Fan Yang;B. Brunschwig;N. Lewis
具有小带隙（< 2ev）的半导体在用作光电极直接从阳光中产生燃料之前，必须在水电解质中稳定防止腐蚀或钝化。此外，为了有效地将H2O氧化为O2(g)，并将H2O或H2O和CO2还原为燃料，需要在光电极表面加入电催化剂。我们在此报道了np(+)-Si（100）和n-Si（111）光阳极在1.0 M KOH（aq）中连续光驱动O2(g)演化超过1200小时的稳定性，这是由一个地球丰富的、光学透明的、电催化的、稳定的、导电的氧化镍层实现的。在模拟太阳光照和优化的抗反射指数匹配条件下，niox涂层的np(+)-Si（100）光阳极产生的光电流起始电位为-180±20 mV（参考O2的平衡演化电位(g)），光电流密度为29±1.8 mA cm(-2)（参考O2的平衡演化电位(g)），太阳能到O2(g)的转换优值为2.1%。
Semiconductors with small band gaps (<2 eV) must be stabilized against corrosion or passivation in aqueous electrolytes before such materials can be used as photoelectrodes to directly produce fuels from sunlight. In addition, incorporation of electrocatalysts on the surface of photoelectrodes is required for efficient oxidation of H2O to O2(g) and reduction of H2O or H2O and CO2 to fuels. We report herein the stabilization of np(+)-Si(100) and n-Si(111) photoanodes for over 1200 h of continuous light-driven evolution of O2(g) in 1.0 M KOH(aq) by an earth-abundant, optically transparent, electrocatalytic, stable, conducting nickel oxide layer. Under simulated solar illumination and with optimized index-matching for proper antireflection, NiOx-coated np(+)-Si(100) photoanodes produced photocurrent-onset potentials of -180 ± 20 mV referenced to the equilibrium potential for evolution of O2(g), photocurrent densities of 29 ± 1.8 mA cm(-2) at the equilibrium potential for evolution of O2(g), and a solar-to-O2(g) conversion figure-of-merit of 2.1%.