Selective hydrobenzoin photosynthesis from benzyl alcohol over AgIn5S8@Zn2In2S5 seamless heterostructures

Photocatalytic benzyl alcohol (BA) conversion is a representative for green and sustainable alcohol valorization and concurrent hydrogen production. However, there lacks of an efficient control over product selectivity, particularly the valuable C-C coupling compound hydrobenzoin. Here, selective hydrobenzoin photosynthesis has been realized by fabricating AgIn 5 S 8 @Zn 2 In 2 S 5 heterostructures (denoted hereafter as AIS@ZIS) for BA conversions. AIS@ZIS are essential type-II semiconductor heterojunctions and is characterized by seamless heterointerfaces that contribute to efficient separation of photocarriers (photo-generated e - and h + ). Such desired properties not only provide ample photocarriers for BA conversion but also switch the reaction sites from Zn 2 In 2 S 5 to AgIn 5 S 8 . The latter is critical for the high selectivity of hydrobenzoin as AgIn 5 S 8 favors hydrobenzoin formation whilst is less favorable for hydrobenzoin oxidation, as revealed by both experimental and theoretical studies. Notably, AIS@ZIS can deliver selectivity higher than 80 %, conversion efficiency higher than 90 % and an apparent quantum yield of 4.89 % at 420 ± 20 nm for hydrobenzoin photosynthesis. These findings not only bring new mechanistic insights for selective hydrobenzoin photosynthesis but also serve as a rational guideline for the design of highly active photocatalysts for efficient organic transformation.