Boosting the performance of Cu2O photocathodes for unassisted solar water splitting devices
Boosting the performance of Cu2O photocathodes for unassisted solar water splitting devices
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DOI：
10.1038/s41929-018-0077-6
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发表时间：
2018-06-01
期刊：
影响因子：
37.8
通讯作者：
Gratzel, Michael
中科院分区：
文献类型：
--
作者：
Pan, Linfeng;Kim, Jin Hyun;Gratzel, Michael
虽然在过去的几十年里，人们对光电化学（PEC）水裂解进行了大量的研究，但缺乏高效、稳定和地球丰富的光电极仍然是实际应用的瓶颈。在这里，我们报告了一个光电阴极的同轴纳米线结构实现了一个Cu 2 O/Ga 2 O3掩埋的p-n结，实现了有效的光收集在整个可见光区域超过600 nm，达到了外部量子产氢接近80%。对于可逆氢电极，光电流起始超过+1V，并且对于可逆氢电极，在0 V下的光电流密度为-10mA cm（-2），我们的电极构成了目前已知的用于从太阳光催化产生氢的最佳氧化物光电阴极。通过TiO 2保护层的原子层沉积实现的保形涂层可实现超过100小时的稳定运行。以NiMo为析氢催化剂，在弱碱性电解液中获得了稳定工作的全地球丰度Cu 2 O光电阴极。为了显示这种光电阴极的实际影响，我们使用最先进的BiVO 4作为光电阳极构建了全氧化物无辅助太阳能水裂解串联装置，实现了~ 3%的太阳能-氢气转化效率。
Although large research efforts have been devoted to photoelectrochemical (PEC) water splitting in the past several decades, the lack of efficient, stable and Earth-abundant photoelectrodes remains a bottleneck for practical application. Here, we report a photocathode with a coaxial nanowire structure implementing a Cu2O/Ga2O3-buried p-n junction that achieves efficient light harvesting across the whole visible region to over 600 nm, reaching an external quantum yield for hydrogen generation close to 80%. With a photocurrent onset over +1V against the reversible hydrogen electrode and a photocurrent density of -10 mA cm(-2) at 0 V versus the reversible hydrogen electrode, our electrode constitutes the best oxide photocathode for catalytic generation of hydrogen from sunlight known today. Conformal coating via atomic-layer deposition of a TiO2 protection layer enables stable operation exceeding 100 h. Using NiMo as the hydrogen evolution catalyst, an all Earth-abundant Cu2O photocathode was achieved with stable operation in a weak alkaline electrolyte. To show the practical impact of this photocathode, we constructed an all-oxide unassisted solar water splitting tandem device using state-of-the-art BiVO4 as the photoanode, achieving -3% solar-to-hydrogen conversion efficiency.