Hydrogen-evolution characteristics of Ni–Mo-coated, radial junction, n+p-silicon microwire array photocathodes
Hydrogen-evolution characteristics of Ni–Mo-coated, radial junction, n+p-silicon microwire array photocathodes
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DOI：
10.1039/c2ee23192a
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发表时间：
2012-10
影响因子：
32.5
通讯作者：
E. Warren;James R. McKone;H. Atwater;H. Gray;N. Lewis
中科院分区：
文献类型：
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作者：
E. Warren;James R. McKone;H. Atwater;H. Gray;N. Lewis
基于太阳能电池的热力学能量转换效率和优值，对Ni-Mo涂层径向n+p结硅微线（Si MW）阵列的光阴极析氢性能进行了评价。Ni-Mo涂层的n+p-Si MW电极在模拟的1个太阳光照下产生0.46 V的开路光电压（Voc），9.1 mA cm−2的短路光电流密度（Jsc）和1.9%的基于电容的能量转换效率（η）。在名义上相同的条件下，Ni-Mo涂层系统的效率与Pt涂层n+p-Si MW阵列光电阴极的效率相当（Voc = 0.44 V，Jsc = 13.2 mA cm−2，η = 2.7%）。这表明，在高表面积微丝阵列上，在1太阳光强度下，地球丰富的电催化剂可以提供与贵金属催化剂相当的光电化学析氢性能。在微丝上形成发射极层使得基于微丝阵列的光电阴极的开路电压相对于不具有掩埋n+p结的Si MW阵列得到显著改善。这些设备的光谱响应和光强度依赖性的分析允许优化的催化剂负载和光电流密度。还将微丝阵列从基板上移除，以创建具有在太阳能水分解装置中使用的潜力的柔性析氢膜。
The photocathodic H2-evolution performance of Ni–Mo-coated radial n+p junction Si microwire (Si MW) arrays has been evaluated on the basis of thermodynamic energy-conversion efficiency as well as solar cell figures of merit. The Ni–Mo-coated n+p-Si MW electrodes yielded open-circuit photovoltages (Voc) of 0.46 V, short-circuit photocurrent densities (Jsc) of 9.1 mA cm−2, and thermodynamically based energy-conversion efficiencies (η) of 1.9% under simulated 1 Sun illumination. Under nominally the same conditions, the efficiency of the Ni–Mo-coated system was comparable to that of Pt-coated n+p-Si MW array photocathodes (Voc = 0.44 V, Jsc = 13.2 mA cm−2, η = 2.7%). This demonstrates that, at 1 Sun light intensity on high surface area microwire arrays, earth-abundant electrocatalysts can provide performance comparable to noble-metal catalysts for photoelectrochemical hydrogen evolution. The formation of an emitter layer on the microwires yielded significant improvements in the open-circuit voltage of the microwire-array-based photocathodes relative to Si MW arrays that did not have a buried n+p junction. Analysis of the spectral response and light-intensity dependence of these devices allowed for optimization of the catalyst loading and photocurrent density. The microwire arrays were also removed from the substrate to create flexible, hydrogen-evolving membranes that have potential for use in a solar water-splitting device.