Understanding on the roles of oriented-assembly-constructed defects in design of efficient AIS-based photocatalysts for boosting photocatalytic H2 evolution

Abstract

High defect tolerance and versatile surface engineering of AgInS2 (AIS) provide platforms to design donor-band (DB) regulated Zn-alloyed AIS (ZAIS) for effective photocatalytic H2 evolution (PHE). After that, understanding the correlations among DB-related defects, Zn-alloying, and ZnS shell plays critical roles in the design of effective photocatalysts. Initially, the growth kinetics of GSH-capped AIS QDs involving size and defects evolution and the evolution of the PHE rates for samples corresponding to growth kinetics were investigated. In combination with structural characterization, steady-transient photoluminescence (PL) analysis suggests these planar defects constructed via oriented assembly are responsible for enhanced PHE. TGA-assisted Zn-alloying or ZnS deposition was further developed to stabilize or passivate these defects and led to Zn-alloyed AIS (i.e., ZAIS) QDs, or core-shelled AIS@ZnS and ZAIS@ZnS nanocrystals, respectively. Structural investigations confirmed samples' crystal structures, aggregation-related morphologies, and microstructure. Steady-transient PL and transient photocurrent response suggest improved carriers’ separation/transfer in this ZAIS, while a significant decrease in carriers’ separation/transfer in the corresponding ZnS-shelled counterpart. As a result, the ZAIS shows superior PHE rates of 2.01 mmol. g−1. h−1, ∼ 3.6 times higher than AIS QDs or 11.8 times higher than AIS@ZnS (0.17 mmol. g−1. h−1). Based on band alignment analysis, the total decrease of PHE of AIS@ZnS or ZAIS@ZnS can be ascribed to the passivation of DB-related defects. This work is expected to provide new insight for designing core-shelled or alloy ternary QDs for effective PHE. Data Availability StatementThe raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.