Functionalized Sr2MgSi2O7:(Eu,Dy)@CdS heterojunction photocatalyst for round-the-clock hydrogen production

Photocatalytic hydrogen production from water splitting is a crucial strategy for reducing carbon emissions. However, achieving round-the-clock photocatalytic hydrogen production is challenging due to insufficient photocatalytic activity and intermittent solar flux. To circumvent this issue, a Sr2MgSi2O7:(Eu,Dy)@CdS heterojunction photocatalyst is designed to realize round-the-clock photocatalytic hydrogen production. The type II heterojunction effectively suppresses the recombination of photogenerated charge carriers. Sr2MgSi2O7:(Eu,Dy) is of paramount importance in generating long-lived charges and guiding charge transfer, providing the necessary photoenergy for driving photocatalysis in the dark. Sr2MgSi2O7:(Eu,Dy)@CdS exhibits a remarkable UV-vis-driven hydrogen generation of 18.07 mmol g-1 in 0.5 hour and a dark activity of 6.31 mmol g-1 lasting 4 hours, which surpass most previously reported materials. The photocatalytic mechanism is comprehensively investigated through photophysical and electrochemical properties, energy band structure, unique charge transfer paths and first-principles calculations. This work provides a promising strategy to design photocatalysts for round-the-clock photocatalytic hydrogen production.