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 μmol g–1 h–1, much higher than that of the sample without calcination treatment (639 μmol 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.