Bismuth vanadate (BiVO) is a promising n-type photoanode material for photoelectrochemical (PEC) water splitting. However, its activity is impeded by poor charge carrier transport and sluggish oxygen evolution kinetics. In this study, we reports a Fe doping and caffeic acid (CA)/NiFeOOH (NiFe) modification with BiVO photoanode (NiFe/CA/Fe-BiVO) to enhance the PEC water oxidation performance and stability. The modified BiVO demonstrates significant advantages in promoting the PEC performance and stability. Specifically, Fe doping via in-situ electro-deposition results in smaller crystal sizes, larger specific surface areas, and more exposed active sites. Furthermore, co-catalyst NiFe connects with Fe-BiVO through CA bridge facilitates a more uniform self-assembly distribution of NiFe on BiVO surface. The NiFe/CA/Fe-BiVO exhibits an excellent photocurrent density of 6.2 mA/cm at 1.23 Vand demonstrates good stability at 0.8 V. In addition, the composite photoanode shows a high applied bias photon-to-current efficiency (ABPE) value of 2.15% at 0.65 V. EPR and in-situ FTIR confirm the generation of superoxide active species (O and ·O) during the PEC water oxidation reaction.

中文翻译：

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通过咖啡酸桥接 NiFeOOH 提高 BiVO4 光阳极的光电催化析氧活性


钒酸铋（BiVO）是一种有前途的用于光电化学（PEC）水分解的n型光阳极材料。然而，其活性受到载流子传输不良和析氧动力学缓慢的阻碍。在这项研究中，我们报道了用 BiVO 光阳极 (NiFe/CA/Fe-BiVO) 进行 Fe 掺杂和咖啡酸 (CA)/NiFeOOH (NiFe) 修饰，以增强 PEC 水氧化性能和稳定性。修饰后的 BiVO 在提升 PEC 性能和稳定性方面表现出显着优势。具体来说，通过原位电沉积进行铁掺杂会导致更小的晶体尺寸、更大的比表面积和更多的暴露活性位点。此外，助催化剂NiFe通过CA桥与Fe-BiVO连接，有利于NiFe在BiVO表面上更均匀的自组装分布。 NiFe/CA/Fe-BiVO 在 1.23 V 下表现出 6.2mA/cm 的优异光电流密度，在 0.8V 下表现出良好的稳定性。此外，复合光电阳极表现出较高的外加偏压光子电流效率 (ABPE) 值。 0.65V 时为 2.15%。EPR 和原位 FTIR 证实在 PEC 水氧化反应过程中产生了超氧化物活性物质（O 和·O）。