Harvesting the infrared part of solar light to promote charge transfer in Bi 2 S 3 /WO 3 photoanode for enhanced photoelectrochemical water splitting

Infrared light absorbed by semiconductors hardly contributes to the solar energy conversion due to its low photon energy. Herein, photothermal effect activated by infrared part of solar light is introduced to promote the photoelectrochemical (PEC) water splitting of photoanodes. Narrow band-gap semiconductor Bi S is deposited on the surface of WO nanosheets, exhibiting a broad-spectral response. In addition to the enhanced density of photo-generated electrons, significant temperature elevation is observed for the Bi S /WO composite photoanode under the illumination of infrared part of solar light because of the photothermal conversion property of Bi S . The moderately enhanced temperature accelerates charge carrier migration and finally increases the efficiency of solar energy conversion. With the assistance of photothermal effect, a remarkable photocurrent density of 4.05 mA cm at 1.23 V vs. reversible reference electrode (V ) is achieved by Bi S /WO composite photoanode, over 880% higher than that of the pristine WO . The introduction of photothermal effect activated by infrared light provides general and robust strategy to promote the PEC performance of photoanodes.