Unraveling Electron-deficient Setaria-viridis-like Co3O4@MnO2 heterostructure with superior photoelectrocatalytic efficiency for water remediation

Abstract

Photoelectrocatalytic (PEC) degradation efficiency of refractory organic pollutants depends strongly on the characteristics of photoanode semiconductors. Therefore, choosing a photoanode semiconductor material to enhance the PEC efficiency is a critical problem. Here, we assemble a unique Co3O4@(δ-)MnO2 setaria-viridis-like heterostructure employing a two-step hydrothermal method. To maximize PEC degradation efficiency, coupling Co3O4 with an appropriate amount of MnO2 achieves Co3O4@MnO2-0.05, resulting in high oxygen evolution potential, fast carrier transfer, low resistance, electron-deficient surface, and high photo-response current. Those properties endow Co3O4@MnO2-0.05 as a promising candidate for practice application of dye degradation, with a degradation rate of ∼ 94.8 % and long-term durability (∼12000 s) under 1.0 mol·L−1 H2SO4 condition at a current density of 250 mA·cm−2 for blue KN-R degradation. Remarkably, the superior PEC degradation efficiency of Co3O4@MnO2-0.05 outperformed that of Co3O4-based and MnO2-based catalysts due to the dominant role of •O2− and h+ radical during degradation experiments.