Fabricating Bi2MoO6@Co3O4 core–shell heterogeneous architectures with Z‑scheme for superior photoelectrocatalytic water purification

Abstract

The decomposition efficiency of refractory organic contaminants depends strongly on the characteristics of photoanode semiconductors during the photoelectrocatalytic (PEC) process, and selecting an excellent material with superior PEC efficiency is a challenge for the current PEC oxidation technique's practical application. Herein, a novel Bi2MoO6@Co3O4 hierarchical core–shell heterogeneous photoanode is fabricated by the simple hydrothermal process. Moreover, the amount of Bi2MoO6 nanosheets adhered to the surface of the Co3O4 nanowire can be easily tuned by changing the concentration of the Bi2MoO6 precursor solution. The as-prepared Bi2MoO6@Co3O4 photoanode exhibited larger electroactive surface area, lower charge transfer resistance, more negative flat band potential, and high separation efficiency of induced e-/h+ pairs, as compared with that of bare Co3O4 nanowire. It is worth mentioning that the Z-scheme heterojunction structure formed by the combination of Bi2MoO6 and Co3O4 maintained the more vital redox ability of induced e-/h+. Consequently, the as-prepared Bi2MoO6@Co3O4 photoanodes showed better PEC performance than Bi2MoO6 or Co3O4 for the degradation of reactive brilliant blue KN-R. The optimized Bi2MoO6@Co3O4-2.0 exhibited the highest degradation rate of 88.43% and accelerated stability of 110 min at the current density of 500 mA·cm−2 in 1.0 mol·L-1 H2SO4 solution. The strategy of fabricating core–shell heterostructure Bi2MoO6@Co3O4 photoanode with superior PEC efficiency may guide other heterogeneous designs.