Double functionalization of Mo ₂ C and NiMn‐LDH assembling g‐C ₃ N ₄ as efficient bifunctional electrocatalysts for selective electrocatalytic reactions and overall water splitting

Abstract

Summary Recently, the development of durable electrocatalysts with bifunctional and high‐efficiency applications in overall water splitting has become a hot spot in the energy field. Herein, Mo2C@g‐C3N4@NiMn‐LDH, a bifunctional electrocatalyst, is obtained through self‐assembly strategies of heat treatment, g‐C3N4 coating, and hydrothermal growth of NiMn‐LDH nanosheets using homogeneous Mo2C precursor nanowire as template. Specifically, Mo2C and NiMn‐LDH are located on the inner wall and outer wall of g‐C3N4, respectively, realizing separate‐sided different functions of g‐C3N4 by electronic control of the interface. The Mo2C@g‐C3N4@NiMn‐LDH composite exhibits excellent bifunctional electrocatalytic performance, in which the inner Mo2C@g‐C3N4 are the dominant catalytic active center for hydrogen evolution reaction (HER) and the outer NiMn‐LDH acts as co‐catalyst, whereas the active center transfer to g‐C3N4@NiMn‐LDH for oxygen evolution reaction (OER) and the inner Mo2C turns into the co‐catalyst. The performance of Mo2C@g‐C3N4@NiMn‐LDH electrocatalyst is reflected by the overpotential of 116 mV (for HER) and 290 mV (for OER) at the current density of 10 mA cm−2 in alkaline medium, respectively. In addition, the voltage required for overall water splitting to reach 10 mA cm−2 is only 1.587 V, and the sample has excellent stability under constant applied voltage. This work provides a strategy for the development of high‐performance electrocatalysts with controllable active sites through interface engineering, so as to achieve competitive equilibrium of different reaction processes.

Interfacing NiV layered double hydroxide with sulphur-doped g-C3N4 as a novel electrocatalyst for enhanced hydrogen evolution reaction through Volmer–Heyrovský mechanism

“…34 The Mo 2 C@g-C 3 N 4 @NiMn-LDH tertiary composite showed functional activity towards the HER and the OER in an alkaline medium, with respective overpotentials of 116 mV and 298 mV at 10 mA cm −2 . 35 Based on these reports, a composite between NiV LDH, which has high conductivity and high catalytic activity, and g-C 3 N 4 may significantly improve the catalytic activity of g-C 3 N 4 . For photocatalytic and photoelectrochemical water splitting, most studies on g-C 3 N 4 have focused on band-gap modification via heterojunction formation.…”