Modulating negative magnetoresistance via inducing vacancy for regulates electron transport under magnetic ambient conditions.

The introduction of external magnetic field is one of the most widely studied strategies for photogenerated carrier separation in recent years. However, magnetic materials have great disadvantages in terms of photocatalytic performance. Semiconductor materials with magnetic properties are also extremely rare. It is extremely peculiar to research the magnetism of semiconductor photocatalyst triggered by vacancy. Here, the first example of ferromagnetic Bi 2 S 3 is achieved by controlled Bi vacancy (Bi 2 S 3 -V Bi). The magnetism properties depends largely on the spin polarization of p electrons in S atoms, and its magnetic moment is mainly distributed on S atoms around cation vacancies. Under the induction of external magnetic field, the tunneling of spin-polarized electrons in S-2p orbital makes Bi 2 S 3 -V Bi have negative magnetoresistance effect. The ferromagnetic arrangement of Bi 2 S 3 -V Bi particles can reduce the resistivity and increase the tunneling of electrons. Meanwhile, Lorentz force generated by external magnetic field acts reversely on photogenerated electrons and holes, thus effectively inhibiting the recombination of carriers in photocatalyst. Moreover, the influence of Bi vacancy on Bi 2 S 3 magnetism is investigated by DFT calculation. This study provides a new strategy for effective carrier separation in photocatalysis. Schematic diagram of photocatalytic reaction mechanism induced by negative magnetoresistance effect and Lorentz force. [Display omitted] • For the first time, the introduction of Bi vacancy makes Bi 2 S 3 ferromagnetic. • Bi 2 S 3 -V Bi nanoparticles tunneling can induce negative magnetoresistance effect. • Under the action of external magnetic field, Lorentz force inhibits the separation of photogenerated carriers. • The hydrogen production rate of CdS/Bi 2 S 3 -V Bi reaches 9.93 mmol g−1 h−1 and has excellent cycle stability. [ABSTRACT FROM AUTHOR]