Strengthening Bonding Interaction of a (Co<sub>0.91</sub>V<sub>0.09</sub>)<sub>3</sub>(BTC)<sub>2</sub> Metal–Organic Framework with BiVO<sub>4</sub> Photoanodes Enabling Ultrastable Photoelectrochemical Water Oxidation
Liangcheng Xu, Yingjuan Zhang, Boyan Liu, Kang Wan, Xin Wang, Tingsheng Wang, Lianzhou Wang, Songcan Wang, Wei Huang
Abstract
Although the oxygen evolution reaction (OER) activity of BiVO 4 photoanodes has been significantly enhanced, achieving long-term photostability is still challenging due to the gradual dissolution of V 5+ during photoelectrochemical (PEC) water splitting. Herein, we deliberately generate ligand defects in a (Co 0.91 V 0.09 ) 3 (BTC) 2 metal–organic framework (CoV-MOF) that creates more undercoordinated sites, forming strong chemical bonds with BiVO 4 . Consequently, the dissolution of V 5+ from BiVO 4 during PEC water splitting can be effectively suppressed, leading to significantly enhanced stability. The optimized Co 3 O 4 /CoV-MOF/BiVO 4 photoanode exhibits a high photocurrent density of 6.0 mA cm –2 at 1.23 V vs the reversible hydrogen electrode (RHE). Impressively, the photoanode can stably operate for 500 h at 0.6 V vs RHE under AM 1.5 G illumination. This work demonstrates the proof-of-concept of anchoring V 5+ in BiVO 4 photoanodes achieving ultrastable PEC water splitting.