We describe here a simple, efficient and stable CdSe QDs/NiO photocathode engineered using a molecular linker, mercaptoacetic acid (MAA), for H2 generation from neutral water. This protocol does not require any sacrificial reagent, external cocatalyst, protecting layer and buffer solution as well. Upon visible-light irradiation, photocurrent as high as ?60 μA cm?2 is achieved at a bias of ?0.1 V vs. NHE in 0.1 M Na2SO4 (pH 6.8). Simultaneously, the photocathode evolves H2 consistently for 45 h with ~100% Faradic efficiency, which is unprecedented in the field of sensitized photocathodes for H2 production. A mechanistic study reveals that the exceptional performance is derived from the efficient hole transfer process. Energy Environ. Sci., 2015 |