ZnSe Nanorods as Visible-Light Absorbers for Photocatalytic and Photoelectrochemical H2 Evolution in Water.

ABSTRACT: A precious-metal- and Cd-free photocatalyst system for efficient H2 evolution from aqueous protons with a performance comparable to Cd-based quantum dots is presented. Rod-shaped ZnSe nanocrystals (nanorods, NRs) with a Ni(BF4 )2 co-catalyst suspended in aqueous ascorbic acid evolve H2 with an activity up to 54±2?mmol H2 ?gZnSe -1 ?h-1 and a quantum yield of 50±4?% (?=400?nm) under visible light illumination (AM?1.5G, 100?mW?cm-2 , ?>400?nm). Under simulated full-spectrum solar irradiation (AM?1.5G, 100?mW?cm-2 ), up to 149±22?mmol H2 ?gZnSe -1 ?h-1 is generated. Significant photocorrosion was not noticeable within 40?h and activity was even observed without an added co-catalyst. The ZnSe NRs can also be used to construct an inexpensive delafossite CuCrO2 photocathode, which does not rely on a sacrificial electron donor. Immobilized ZnSe NRs on CuCrO2 generate photocurrents of around -10??A?cm-2 in an aqueous electrolyte solution (pH?5.5) with a photocurrent onset potential of approximately +0.75?V vs. RHE. This work establishes ZnSe as a state-of-the-art light absorber for photocatalytic and photoelectrochemical H2 generation.

SUBMITTER: Kuehnel MF 

PROVIDER: S-EPMC6492148 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature