Improving Stability and Photoelectrochemical Performance of BiVO4 Photoanodes in Basic Media by Adding a ZnFe2O4 Layer

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• 作者：Tae Woo Kim ; Kyoung-Shin Choi
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：February 4, 2016
• 年：2016
• 卷：7
• 期：3
• 页码：447-451
• 全文大小：371K
• ISSN：1948-7185

文摘

BiVO<sub>4sub> photoanodes have mainly been investigated under neutral conditions because BiVO<sub>4sub> gradually dissolves under extreme pH conditions. In this study, the possibility of utilizing ZnFe<sub>2sub>O<sub>4sub> as a protection layer to stabilize BiVO<sub>4sub> in a 0.1 M KOH solution was investigated. A 10–15 nm thick ZnFe<sub>2sub>O<sub>4sub> layer was conformally placed on a nanoporous BiVO<sub>4sub> electrode by photodepositing a FeOOH layer, followed by drop casting a zinc nitrate solution and annealing. The resulting BiVO<sub>4sub>/ZnFe<sub>2sub>O<sub>4sub> electrode generated a photocurrent density of >2 mA/cm<sup>2sup> at 1.23 V versus RHE with a significantly improved stability compared with the pristine BiVO<sub>4sub> electrode. The incident and absorbed photon-to-current conversion efficiencies along with absorption spectra suggested that the ZnFe<sub>2sub>O<sub>4sub> protection layer also contributes to photocurrent generation by increasing photon absorption and electron–hole separation. These results suggest that further investigation of protection and catalyst layers can enable more stable and efficient operation of BiVO<sub>4sub>-based photoanodes in basic media.