Efficient BiVO4 Thin Film Photoanodes Modified with Cobalt Phosphate Catalyst and W-doping
Efficient BiVO4 Thin Film Photoanodes Modified with Cobalt Phosphate Catalyst and W-doping
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DOI：
10.1002/cctc.201200472
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发表时间：
2013-02-01
期刊：
影响因子：
4.5
通讯作者：
van de Krol, Roel
中科院分区：
文献类型：
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作者：
Abdi, Fatwa F.;Firet, Nienke;van de Krol, Roel
采用喷雾热解法制备了用于光诱导水氧化的钒酸铋薄膜光阳极。所得薄膜具有高质量，如在360和450 nm之间的内部量子效率接近100%所示。然而，其在AM1.5照明下的性能受到缓慢的水氧化动力学的限制。这可以通过使用磷酸钴（Co-Pi）作为水氧化助催化剂来解决。在BiVO_4表面电沉积30 nm Co-Pi催化剂，在高于1.2V的电位下（相对于可逆氢电极（RHE）），水的氧化效率从约30%提高到90%以上。一旦去除表面催化限制，光电阳极的性能就受到低电荷分离效率的限制;超过60%的电子-空穴对在到达各自的界面之前重新组合。慢的电子传输被证明是这种低效率的主要原因。我们表明，这可以通过在BiVO 4中引入W作为施主型掺杂剂来补救，从而导致在1.23V与RHE的1%W掺杂的Co-Pi催化的BiVO 4的AM1.5光电流接近2.3mAcm2。
Bismuth vanadate (BiVO4) thin film photoanodes for light-induced water oxidation are deposited by a low-cost and scalable spray pyrolysis method. The resulting films are of high quality, as indicated by an internal quantum efficiency close to 100% between 360 and 450nm. However, its performance under AM1.5 illumination is limited by slow water oxidation kinetics. This can be addressed by using cobalt phosphate (Co-Pi) as a water oxidation co-catalyst. Electrodeposition of 30nm Co-Pi catalyst on the surface of BiVO4 increases the water oxidation efficiency from approximate to 30% to more than 90% at potentials higher than 1.2V vs. a reversible hydrogen electrode (RHE). Once the surface catalysis limitation is removed, the performance of the photoanode is limited by low charge separation efficiency; more than 60% of the electron-hole pairs recombine before reaching the respective interfaces. Slow electron transport is shown to be the main cause of this low efficiency. We show that this can be remedied by introducing W as a donor type dopant in BiVO4, resulting in an AM1.5 photocurrent of approximate to 2.3mAcm2 at 1.23V vs. RHE for 1% W-doped Co-Pi-catalyzed BiVO4.