Su Jin, Hisatomi Takashi, Minegishi Tsutomu, Domen Kazunari
Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Current address: Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK.
Angew Chem Int Ed Engl. 2020 Aug 10;59(33):13800-13806. doi: 10.1002/anie.202000688. Epub 2020 Jun 3.
Most CdTe photoanodes and photocathodes show positive and negative photocurrent onset potentials for water oxidation and reduction, respectively, and are thus unable to drive photoelectrochemical (PEC) water splitting without external applied biases. Herein, the activity of a CdTe photoanode having an internal p-n junction during PEC water oxidation was enhanced by applying a CdCl annealing treatment together with surface modifications. The resulting CdTe photoanode generated photocurrents of 1.8 and 5.4 mA cm at 0.6 and 1.2 V , respectively, with a photoanodic current onset potential of 0.22 V under simulated sunlight (AM 1.5G). The CdCl annealing increased the grain sizes and lowered the density of grain boundaries, allowing more efficient charge separation. Consequently, a two-electrode tandem PEC cell comprising a CdTe-based photoanode and photocathode split water without any external bias at a solar-to-hydrogen conversion efficiency of 0.51 % at the beginning of the reaction.
大多数碲化镉光阳极和光阴极分别对水氧化和还原表现出正和负的光电流起始电位，因此在没有外部施加偏压的情况下无法驱动光电化学（PEC）水分解。在此，通过施加氯化镉退火处理并结合表面改性，提高了具有内部p-n结的碲化镉光阳极在PEC水氧化过程中的活性。所得碲化镉光阳极在模拟太阳光（AM 1.5G）下，在0.6和1.2 V时分别产生1.8和5.4 mA cm的光电流，光阳极电流起始电位为0.22 V。氯化镉退火增加了晶粒尺寸并降低了晶界密度，从而实现了更有效的电荷分离。因此，由碲化镉基光阳极和光阴极组成的双电极串联PEC电池在反应开始时无需任何外部偏压就能分解水，太阳能到氢能的转换效率为0.51%。
