W/O site replace by Ce/N of Bi2WO6 as cations/anions to regulate the reduction potential of conduction band for enhanced photocatalytic degradation and hydrogen evolution capacity

Bismuth tungstate is used as a high potential photocatalytic material, which does not only degrade environmental pollutants but also produces hydrogen for energy use. However, a significant challenge is that the electrochemical potential of its conduction band is more positive, which leads to a weak reduction ability of photogenerated electrons, limiting further improvements in photocatalytic performance and commercial applications. This study proposes a strategy for improving the reduction ability of photo-generated electrons by using Ce/N as a cations anion to partially replace the W/O position in the Bi2WO6 and to regulate the conduction band potential to move negatively. Meanwhile, N-doped energy level is introduced at the top of a valence band to narrow bandgap width and improve visible light absorption ability, as well as make the photoelectric charge move efficiently. First-principles simulation based on DFT is first used to calculate the energy band structure, density of electronic states and charge density of doped Ce/N materials. Theoretically, doped Ce/N ions can cause the conduction band potential to shift negatively and form an impurity level, which is beneficial to light absorption and electron movement. The degradation efficiency of as-prepared BWCeO-4 and BWCeNO-4 up to 95.5% and 85% was achieved within 90 min under visible light irradiation. Hydrogen production reached 16.89 mmol g(-1) and 14.78 mmol g(-1) after 4 h reaction time, respectively. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study proposes a strategy to enhance the reduction ability of photo-generated electrons in bismuth tungstate by doping Ce/N ions, which shifts the conduction band potential negatively and forms an impurity level beneficial to light absorption and electron movement. The as-prepared BWCeO-4 and BWCeNO-4 showed degradation efficiencies of up to 95.5% and 85% within 90 minutes under visible light irradiation, with hydrogen production reaching 16.89 mmol g(-1) and 14.78 mmol g(-1) after 4 hours, respectively.