A Conductive Network and Dipole Field for Harnessing Photogenerated Charge Kinetics.

Liu, Zhaoli; Zhang, Cui; Liu, Lizhi; Zhang, Tianshu; Wang, Jing; Wang, Rong; Du, Ting; Yang, Chengyuan et al. · Adv Mater · 2021

basic_science · Level V

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Abstract

Photogenerated charge separation and directional transfer to active sites are pivotal steps in photocatalysis, which limit the efficiency of redox reactions. Here, a conductive network and dipole field are employed to harness photogenerated charge kinetics by using a Ti<sub>3</sub> C<sub>2</sub> /TiO<sub>2</sub> network (TTN). The TTN exhibits a prolonged charge-carrier lifetime (1.026 ns) and an 11.76-fold increase in hexavalent chromium photoreduction reaction kinetics compared to TiO<sub>2</sub> nanoparticles (TiO<sub>2</sub> NPs). This super photocatalytic performance is derived from the efficient photogenerated charge kinetics, which is steered by the conductive network and dipole field. The conductivity enhancement of the TiO<sub>2</sub> network is achieved by continuous chemical bonds, which promotes electron-hole (e-h) separation. In addition, at the interface of Ti<sub>3</sub> C<sub>2</sub> and TiO<sub>2</sub> , band bending induced by the dipole field promotes photogenerated electron spatially directed transfer to the catalytic sites on Ti<sub>3</sub> C<sub>2</sub> . This study demonstrates that a conductive network and dipole field offer a new concept to harness charge kinetics for photocatalysis.