Constructing internal electric field in CdS via Bi, Ni co-doping strategy for enhanced visible-light H2 production

Abstract

Developing a facile method to build internal electric field in CdS is a promising strategy to realize efficient visible-light H2 production. Herein, we proposed a Bi, Ni co-doping strategy to construct internal electric field in CdS and, thus, restrain the recombination of photogenerated electron-hole pairs, achieving a powerful water splitting photocatalysis. The as-synthesized Bi-, Ni-codoped CdS catalyst (Bi/Ni-CdS) presented a coralloid morphology with a large specific surface area (ca. 150.09 m2/g). Besides, the Bi and Ni dopants could conspicuously narrow the band gap of CdS from 2.2 to 1.5 eV, enhancing its visible-light harnessing ability. Therefore, Bi/Ni-CdS exhibited an enhanced photocatalytic H2 evolution rate of ca. 5294.4 μmol h−1 g−1, which was twentyfold higher than pure CdS under visible-light irradiation (λ ≥ 400 nm). From the test and density functional theory (DFT) calculation results, the doped Bi and Ni atoms could synergistically regulate the electron density of Cd and S atoms and build an internal electric field in Bi10/Ni6-CdS, thereby hindering the charge carriers recombination and increasing hydrogen evolution rate significantly. Furthermore, the excellent water splitting of Bi10/Ni6-CdS related to the improved electrons generation and migration properties as well.