화학공학소재연구정보센터
Journal of Catalysis, Vol.377, 684-691, 2019
Enhanced photoelectrochemical water oxidation activity of BiVO4 by coating of Co-phenolic networks as hole-transfer and co-catalyst
Bismuth vanadate (BiVO4) has been regarded as a promising photoanode material for photoelectrochemical (PEC) water splitting owing to its low cost, and small band gap energy (similar to 2.4 eV). However, the achieved current density of the BiVO4 photoanode remains far below its theoretical value (similar to 7.5 mA cm(-2)) because of its severe surface charge recombination. Herein, a simple process is developed for preparing a new type of low-cost metal-organic coordination composed of tannic acid coordinated with Co ions (TACo) as an efficient cocatalyst to suppress the charge-carrier recombination on BiVO4 photoanodes. For the BiVO4/TACo photoanode, a high photocurrent density of 4.8 mA cm(-2) was achieved at 1.23 V (vs. reversible hydrogen electrode (RHE), AM 1.5 G), which approximately 3-fold higher than that of bare BiVO4. Systematic studies reveal that the enhanced water oxidation performance of BiVO4/TACo photoanode can be ascribed to the synergistic effect of following factors: (i) For the thermodynamic process, the photogenerated holes are directly transferred to TACo layer; (ii) For the kinetic process, the transferred holes can directly oxidied Co2+ to generate Co3+ active sites, which could directly oxidize H2O to molecular O-2. This work provides a new tool-kit for designing efficient water oxidation PECs. (C) 2019 Elsevier Inc. All rights reserved.