Self-Supported Composite of (Ni,Co)<sub>3</sub>C Mesoporous Nanosheets/N-Doped Carbon as a Flexible Electrocatalyst for pH-Universal Hydrogen Evolution
Mengqi Yao, Bojun Wang, Ni Wang, Sridhar Komarneni, Yunjian Chen, Jianwei Wang, Xiaobin Niu, Wencheng Hu
Abstract
Scalable synthesis of highly efficient and nonprecious metal based catalysts for pH-universal hydrogen evolution reaction (HER) is a daunting challenge. In this work, we fabricated self-supported composites of (Ni,Co)3C mesoporous nanosheets/N-doped carbon with adjustable sizes from 1 cm × 1 cm to 25 cm × 25 cm using a facile and rapid electrodeposition, which was then followed by carbonization. The as-prepared catalyst shows small overpotentials of 58, 118, and 71 mV at 10 mA cm–2 in acid, neutral, and basic electrolytes, respectively with high exchange current densities. The above HER activities exceeded most non-noble metal caride-based catalysts in a pH-universal electrolyte. Theoretical calculations suggest that bimetallic carbide is favorable for HER because of its metallic conductivity, close-to-zero Gibbs free energy change (ΔGH*), and downshifted d-band center (εd) revealed by density of states (DOS). The outstanding performance can be attributed to the tunable ultrathin nanosheet-like structure, large specific surface area, and electronic structure modulations. Our work developed an efficient, controllable, and large-scale synthesis of a cost-effective, highly efficient, high performance, and stable catalyst for hydrogen evolution reaction, which can operate in a wide pH range.