Preferential growth and electron trap synergistically promoting photoreduction CO2 of Tm ion doping bismuth titanate nanosheets

Abstract

In this study, we prepared two-dimensional Bi4Ti3O12 nanosheets doped with rare earth ions. The experimental results show that Bi4-xTmxTi3O12 exhibits the highest reduction performance among various rare earth doped Bi4Ti3O12 materials, with a CO yield of 7.25 μmol g−1h−1. Furthermore, a delayed reaction in Bi3.97Tm0.03Ti3O12 is observed upon a cessation of light irradiation. Theoretical calculations reveal that the introduction of Tm ion not only reduces the surface energy of (001) plane and make it preferential growth in Bi4Ti3O12, but also brings the intervening energy level of Tm ion (4f and 4d mixed orbital), which is closer to the conduction band of Bi4Ti3O12 and facilitates charge carrier accumulation in trap states. The electrons retained in the shallow traps promote the hysteresis reaction following a cessation of illumination. This work provides further insights into elucidating precise reduction reaction mechanisms underlying rare earth dopant on photocatalysts. This research provides enhanced insights into unraveling the precise reduction reaction mechanisms influenced by rare earth dopants in photocatalysts.