Surface Phosphorus Grafting of Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene as an Interface Charge “Bridge” for Efficient Electrocatalytic Hydrogen Evolution in All-pH Media
Jian Zhang, Xianzhi Yang, Chen Chen, Yong-Hua Li, Jin Li, Wei Chen, Yan Cui, Xing’ao Li, Xinbao Zhu
Abstract
The interface electronic structure of heterogeneous catalysts can be modulated by changing the surface coordination configuration, which is crucial to their catalytic activity. Herein, a surface phosphorus-grafted Ti 3 C 2 T x MXene platform anchored with an MoS 2 nanoflake heterojunction electrocatalyst was assembled through a simple phosphorus-hydrothermal method. An interface charge “bridge” has been created by grafting uniform P atoms coordinated with the surface O atoms of Ti 3 C 2 T x (P-Ti 3 C 2 T x ), resulting in an interface charge-transfer channel between P-Ti 3 C 2 T x and MoS 2 . Based on the ultrafast transient absorption spectroscopy, the fastest electron-transfer kinetics from P-Ti 3 C 2 T x to MoS 2 (1.7 ps) and the slowest electron–hole recombination speed (28 ps) were obtained over MoS 2 @P-Ti 3 C 2 T x than those over MoS 2 @O-Ti 3 C 2 T x and MoS 2 @OP-Ti 3 C 2 T x . Benefiting from the lower carrier transport activation energy, MoS 2 @P-Ti 3 C 2 T x exhibited the stirring electrocatalytic activity toward hydrogen evolution in all-pH media, which delivered three low overpotentials of 48.6, 63.2, and 70.5 mV at 10 mA cm –2 toward the hydrogen evolution in alkaline, acid, and neutral media, respectively. Grafting an atomic scale “bridge” to create an electron-transfer channel proposes a new strategy to design an efficient pH-universal hydrogen evolution heterojunction electrocatalyst.