Interface and Defect Engineering of a Hollow TiO2@ZnIn2S4 Heterojunction for Highly Enhanced CO2 Photoreduction Activity

Rational engineering of the interfaces or defects of heterojunctions provides an effective strategy to improve their photocatalytic performance but is still a challenge. Herein, we present an ingenious calcination strategy of simultaneously introducing sulfur vacancies and enhancing the interfacial interaction for a hollow TiO2@ZnIn2S4 heterojunction, thus greatly improving the photocatalytic CO2 reduction activity. The low-temperature calcination strategy makes the heterojunction possess both abundant sulfur vacancies and strong interfacial interaction, which lead to an enhanced CO2 photoreduction activity with a CO evolution rate of 1330 mu mol g-1 h-1, much higher than that of the sample without calcination treatment (639 mu mol g-1 h-1). The significantly boosted photocatalytic performance can be ascribed to the improved transfer and separation of photogenerated charges resulting from the intimate heterojunction interface, as well as the strengthened visible-light absorption due to the rich sulfur vacancies. This work presents a feasible and convenient method to optimize the performance of the heterojunction photocatalysts by designing the interfaces and defects.