Carbon-Encapsulated Multimetallic Hybrid Electrocatalyst for Overall Water Splitting and Urea Oxidation

Abstract

Overall water splitting is a hot topic in the development of green energy, but it cannot be generalized on a large scale due to the lack of low-cost and highly efficient overall water-splitting catalysts. As a result, currently, the exploitation of stable and nonprecious metal catalysts with elevated performance has become a research focus in overall water splitting. Here, we introduce a multicomponent material (Ni/MoC/Ti3C2Tx@C) by a strategy of the combination of electrostatic assembly and elevated-temperature calcination to employ it as an electrocatalyst for water splitting and urea oxidation. The Ni/MoC/Ti3C2Tx@C electrocatalyst presents a superior hydrogen evolution reaction and oxygen evolution reaction ability with an overpotential of 128 and 338 mV at 10 mA cm–2 in 1.0 M KOH, respectively, along with long-term stability over 24 h. The Ni/MoC/Ti3C2Tx@C catalyst has a turnover frequency of 1.64 s–1 at 100 mV. Improved catalytic behavior of Ni/MoC/Ti3C2Tx@C is principally due to the synergistic effect of Ni and MoC nanoparticles, the introduction of the conductive Ti3C2Tx MXene matrix with a layered porous structure, and the protection of the carbon layer. In addition, when Ni/MoC/Ti3C2Tx@C electrodes are used to electrolyze water with urea assistance, a voltage of 1.56 V is required for both electrodes to reach 10 mA cm–2, which is 80 mV lower than that required for conventional water electrolysis. Our work provides a strategy for the exploitation of elevated-performance MXene-based electrocatalysts for overall water splitting as well as future advancement of green energy.