Harvesting the infrared part of solar light to promote charge transfer in Bi2S3/WO3 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 Bi2S3 is deposited on the surface of WO3 nanosheets, exhibiting a broad-spectral response. In addition to the enhanced density of photo-generated electrons, significant temperature elevation is observed for the Bi2S3/WO3 composite photoanode under the illumination of infrared part of solar light because of the photothermal conversion property of Bi2S3. 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-2 at 1.23 V vs. reversible reference electrode (VRHE) is achieved by Bi2S3/WO3 composite photoanode, over 880% higher than that of the pristine WO3. The introduction of photothermal effect activated by infrared light provides general and robust strategy to promote the PEC performance of photoanodes. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

The introduction of photothermal effect activated by infrared light enhances the photoelectrochemical (PEC) water splitting performance of photoanodes. The Bi2S3/WO3 composite photoanode achieves a significant temperature elevation under infrared solar light illumination, accelerating charge carrier migration and improving solar energy conversion efficiency.