Fabricating Co3O4–Co2MnO4 based type-II heterostructure architecture with prominent photoelectrocatalytic performance toward water purification

Abstract

Designing heterogeneous micro-nanostructured photoelectrodes based on ideal semiconductor catalytic materials is an efficient method for realizing the practical application of photoelectrocatalysis (PEC) technology. Herein, we propose a one-pot approach for fabricating semiconductor composite heterostructures (Co₃O₄–Co₂MnO₄ architecture), which is a simpler, faster, and more economical method compared with previous layer-by-layer assembly methods. Interestingly enough, coupled Co₃O₄ nanowire/Co₂MnO₄ nanoparticle architecture is fabricated by a one-pot hydrothermal method using cobalt and manganese salts. It can be seen that the micro-nanostructure and PEC performance of Co₃O₄–Co₂MnO₄ architecture can be adjusted by changing the concentration of Mn²⁺ (i.e., ratio of Mn/Co) in the precursor solution. Consequently, the as-prepared Ti/Co₃O₄–Co₂MnO₄ showed better PEC performance for degrading reactive brilliant blue KN-R with 60 mg/L concentration compared with that of Ti/Co₃O₄ and Ti/Co₂MnO₄. The optimized Ti/Co₃O₄–Co₂MnO₄-0.3 exhibited better PEC activity (~ 94.12%) in 2 h for degrading reactive brilliant blue KN-R. The enhancement of PEC performance of Ti/Co₃O₄–Co₂MnO₄ can be proposed to the formation of a type-II heterojunction mechanism between Co₃O₄ and Co₂MnO₄, which promotes the formation of active species (·O₂⁻, and h⁺), leading to good separation of induced carriers. This work provides a feasible strategy for fabrication of coupled semiconductor/semiconductor heterostructure with PEC efficiency using a simplified experimental approach.