Morphology engineering of BiVO4 with CoOx derived from cobalt-containing polyoxometalate as co-catalyst for oxygen evolution.

Li, Xiaohu; Dong, Yinjuan; Hu, Gaoyang; Ma, Kangwei; Chen, Mengxue; Ding, Yong

Bismuth vanadate (BiVO 4 ) as a metal oxidation semiconductor has stimulated extensive attention in the photocatalytic water splitting field. However, the poor transport ability and easy recombination of charge carriers limit photocatalytic water oxidation activity of pure BiVO 4 . Herein, the photocatalytic activity of BiVO 4 is enhanced via adjusting its morphology and combination co-catalyst. First, the Cu-BiVO 4 was synthesized by copper doping to control the growth of {110} facet of BiVO 4 , which is regarded for the separation of photo-generated charge carriers. Then the CoO x in-situ generated from K 6 [SiCo II (H 2 O)W 11 O 39 ]∙16H 2 O was photo-deposited on Cu-BiVO 4 surface as co-catalyst to speed up reaction kinetics. Cu-BiVO 4 @CoO x hybrid catalyst shows highest photocatalytic activity and best stability among all the prpared catalysts. Oxygen evolution is about 34.6 μmol in pH 4 acetic acid buffer under 420 nm LED irradiation, which is nearly 20 times higher than that of pure BiVO 4 . Apparent quantum efficiency (AQE) in 1 h and O 2 yield are 1.83% and 23.1%, respectively. O 2 evolution amount nearly maintain the original value even after 5 cycles.