Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St., Chestnut Hill, MA 02467 (USA); Key Laboratory for Colloid and Interface Chemistry of Education Ministry, Shandong University, 27 South Shanda Road, Jinan, Shandong, 250100 (P.R. China).
Angew Chem Int Ed Engl. 2014 Dec 1;53(49):13493-7. doi: 10.1002/anie.201408375. Epub 2014 Oct 5.
Whereas wide-bandgap metal oxides have been extensively studied for the photooxidation of water, their utilization for photoreduction is relatively limited. An important reason is the inability to achieve meaningful photovoltages with these materials. Using Cu2 O as a prototypical photocathode material, it is now shown that the photovoltage barrier can be readily broken by replacing the semiconductor/water interface with a semiconductor/semiconductor one. A thin ZnS layer (ca. 5 nm) was found to form high-quality interfaces with Cu2 O to increase the achievable photovoltage from 0.60 V to 0.72 V. Measurements under no net exchange current conditions confirmed that the change was induced by a thermodynamic shift of the flatband potentials rather than by kinetic factors. The strategy is compatible with efforts aimed at stabilizing the cathode that otherwise easily decomposes and with surface catalyst decorations for faster hydrogen evolution reactions. A combination of NiMo and CoMo dual-layer alloy catalysts was found to be effective in promoting hydrogen production under simulated solar radiation.
虽然宽禁带金属氧化物已被广泛研究用于水的光氧化，但它们在光还原方面的应用相对有限。一个重要的原因是这些材料无法实现有意义的光电压。使用 Cu2O 作为典型的光电阴极材料，现在表明通过用半导体/半导体界面代替半导体/水界面，可以很容易地打破光电压势垒。发现一层约 5nm 的 ZnS 层与 Cu2O 形成高质量的界面，可以将可实现的光电压从 0.60V 提高到 0.72V。在没有净交换电流条件下的测量证实，这种变化是由平带电位的热力学位移引起的，而不是由动力学因素引起的。该策略与旨在稳定阴极的努力兼容，否则阴极很容易分解，并且与用于更快的析氢反应的表面催化剂装饰兼容。发现 NiMo 和 CoMo 双层合金催化剂的组合在模拟太阳光下有效地促进了氢气的产生。
