BiVO4 nanocrystals with controllable oxygen vacancies induced by Zn-doping coupled with graphene quantum dots for enhanced photoelectrochemical water splitting
BiVO4 nanocrystals with controllable oxygen vacancies induced by Zn-doping coupled with graphene quantum dots for enhanced photoelectrochemical water splitting
复制标题
Zn掺杂诱导的具有可控氧空位的BiVO4纳米晶体与石墨烯量子点相结合，用于增强光电化学水分解
DOI：
10.1016/j.cej.2019.04.161
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发表时间：
2019-09-15
影响因子：
15.1
通讯作者：
Yang, Hui
中科院分区：
文献类型：
--
作者：
Pan, Qingguang;Yang, Kunran;Yang, Hui
BiVO4光阳极的弱电子-空穴对分离和转移限制了其光电化学分解水性能。在这项工作中，我们重点研究锌掺杂来取代 BiVO4 纳米晶体中的 Bi 位点，以促进有效的电荷分离和转移。理论和实验结果表明，Zn掺杂会产生含量可控的氧空位。 Zn掺杂和氧空位不仅改变了BiVO4的导带和价带位置，产生局部内建电场，而且增加了载流子密度，有利于电荷分离和转移。同时，Bisites上的水吸附也被激活，这将有助于水的分解。因此，这些贡献协同增强了光电化学性能，0.6 V vs. RHE 下的入射光子到电流转换效率 (IPCE) 为 34%，远高于原始 BiVO4。此外，通过依次电沉积石墨烯量子点（GQDs）和磷酸钴（Co-Pi）纳米薄膜，我们构建了杂化ZnBiVO4/GQDs/Co-Pi结构，以拓宽光吸收并增强稳定性，其IPCE高达57%，光电流密度在0.6 V vs. RHE下达到3.01 mA cm(-2)，是原始结构的8.6倍BiVO4，从而为BiVO4基光电极的结构设计提供了有效的策略。
The weak electron-hole pair separation and transfer of the BiVO4 photoanode restrain its photoelectrochemical performance of water splitting. In this work, we focus on Zn doping to replace Bi-sites within BiVO4 nanocrystals to promote efficient charge separation and transfer. Theoretical and experimental results show that Zn doping induces oxygen vacancies with controllable content. Zn doping and oxygen vacancies not only shift the conduction and valance band positions of BiVO4, resulting a local built-in electric field, but also increase the carrier density, which would be beneficial for charge separation and transfer. In the meantime, water adsorption on Bisites is also activated, which would help water splitting. As a result, these contributions synergistically enhance photoelectrochemical performance with the incident photon-to-current conversion efficiency (IPCE) of 34% at 0.6 V vs. RHE, which is much higher than that of pristine BiVO4. Furthermore, by sequentially electrodepositing graphene quantum dots (GQDs) and cobalt phosphate (Co-Pi) nano-film, we have constructed a hybrid ZnBiVO4/GQDs/Co-Pi structure to broaden the light absorption and to enhance the stability, its IPCE reaches as high as 57% and photocurrent density achieves 3.01 mA cm(-2) at 0.6 V vs. RHE, which is 8.6 times of the pristine BiVO4, thus providing an efficient strategy for the structure design of BiVO4 based photoelectrodes.