Unveiling Hierarchical Dendritic Co3O4-SnO2 Heterostructure for Efficient Water Purification

The construction of a desirable, environmentally friendly, and cost-effective nanoheterostructure photoanode to treat refractory organics is critical and challenging. Herein, we unveiled a hierarchical dendritic Co3O4-SnO2 heterostructure via a sequential hydrothermal process. The time of the secondary hydrothermal process can control the size of the ultrathin SnO2 nanosheets on the basis of the Ostwald solidification mass conservation principle. Ti/Co3O4-SnO2-168h with critical growth size demonstrated a photoelectrocatalysis degradation rate of similar to 93.3% for a high dye concentrate of 90 mg/L with acceptable long-term cyclability and durability over reported Co3O4-based electrodes because of the large electrochemically active area, low charge transfer resistance, and high photocurrent intensity. To gain insight into the photoelectric synergy, we proposed a type-II heterojunction between Co3O4 and SnO2, which prevents photogenerated carriers' recombination and improves the generation of dominant active species center dot O2 -, 1O2, and h+. This work uncovered the Ti/Co3O4-SnO2-168 as a promising catalyst and provided a simple and inexpensive assembly strategy to obtain binary integrated nanohybrids with targeted functionalities.

Automated summary

In this study, a hierarchical dendritic Co3O4-SnO2 heterostructure was prepared via a sequential hydrothermal process for treating refractory organics. The size of the ultrathin SnO2 nanosheets can be controlled by the time of the secondary hydrothermal process. Ti/Co3O4-SnO2-168h showed a photoelectrocatalysis degradation rate of approximately 93.3% for a high dye concentrate, with good long-term cyclability and durability. The proposed type-II heterojunction between Co3O4 and SnO2 prevents carrier recombination and enhances the generation of active species.