Schottky barrier tuning via surface plasmon and vacancies for enhanced photocatalytic H2 evolution in seawater

Although Schottky barriers at the interface of metal/semiconductor help electron/hole separation in photocatalysis, they also limit the migration of electrons across the interface. Herein, we tune Schottky barriers over Ni/S vacancy-rich Mn0.3Cd0.7S (Ni/MCS-s) composites prepared by self-assembly and photochemical method. The Ni/MCS-s heterostructures exhibits superior hydrogen production activity up to 164.1 mmol/h/g in simulated seawater (3.5 wt% NaCl), which is 68 and 5 times higher than MCS-s and 1 wt% Pt/MCS-s, respectively. The apparent quantum yield reached 60.4% at 420 nm. The excellent photocatalytic performance of Ni/MCS-s results from the coupling of plasmonic Ni and S vacancies, which can effectively lower Schottky barrier and enhance hot electrons across the interface for photocatalytic process. Moreover, the Ni layer effectively prevents the catalyst from being corroded in seawater. This work provides a feasible strategy for designing efficient photocatalysts for solar energy conversion in seawater.