Surface Photovoltage Measurements on a Particle Tandem Photocatalyst for Overall Water Splitting
Surface Photovoltage Measurements on a Particle Tandem Photocatalyst for Overall Water Splitting
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DOI：
10.1021/acs.nanolett.7b04020
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发表时间：
2018-02-01
期刊：
影响因子：
10.8
通讯作者：
Osterloh, Frank E.
中科院分区：
文献类型：
--
作者：
Melo, Mauricio A., Jr.;Wu, Zongkai;Osterloh, Frank E.
表面光电压谱（SPS）用于测量Ru-STiO 3：Rh/BiVO 4颗粒串联整体水裂解光催化剂上的光电势。该串联由Ru修饰的SrTiO 3：Rh纳米晶和BiVO 4微晶通过静电组装然后热退火合成。它将水分解为H-2和O-2，在435 nm处的表观量子效率为1.29%，太阳能转化为氢的效率为0.028%。根据SPS，光电压发展超过2.20 eV，串联的有效带隙，并在435 nm处达到其最大值-2.45 V（2.44 mW cm（-2）），其对应于在氟掺杂的氧化锡涂覆的玻璃（FTO）基底上的光催化剂膜的理论极限的96%：电荷分离是82%可逆的，其中18%的电荷载流子被捕获在缺陷态中。异常强烈的光电压（每十年1.16 V）的光强度依赖性是由于耗尽层内的BiVO 4微晶的变化。这些发现促进了对无机粒子光催化剂转化太阳能的理解。
Surface photovoltage spectroscopy (SPS) is used to measure the photopotential across a Ru-STiO3:Rh/BiVO4 particle tandem overall water splitting photocatalyst. The tandem is Synthesized from Ru-modified SrTiO3:Rh nanocrystals and BiVO4 microcrystals by electrostatic assembly followed by thermal annealing. It splits water into H-2 and O-2 with an apparent quantum efficiency of 1.29% at 435 nm and a Solar to hydrogen conversion efficiency of 0.028%. According to SPS, a photovoltage develops above 2.20 eV, the effective band gap of the tandem, and reaches its maximal value of -2.45 V at 435 nm (2.44 mW cm(-2)), which corresponds to 96% of the theoretical limit of the photocatalyst film on the fluorine-doped tin-oxide-coated glass (FTO) substrate: Charge separation is 82% reversible with 18% of charge Carriers being trapped in defect states. The unusually strong light intensity dependence of the photovoltage (1.16 V per decade) is attributed to depletion layer changes inside of the BiVO4 microcrystals. These findings promote the understanding, of solar energy conversion with inorganic particle photocatalysts.