Systematic Engineering on Ni-Based Nanocatalysts Effectively Promote Hydrogen Evolution Reaction

Designing a synthesis of ultra-small Ni-based nanomaterials with high intrinsic activity and stability in alkaline hydrogen evolution reaction (HER) is a major challenge. Herein, a series of noble metal doped ultra-small size (4 nm) M-Ni/NiO nanoparticles supported on CNT are rationally designed by a solvent-free microwave reduction method that is fast (60 s), simple, includes no surfactants, extensive (>1 g), and has high yield (82.7%). The Ir-Ni/NiO@CNT has superior performance with a low overpotential of 24.6 mV at 10 mA cm(-2). In addition, the turnover frequency (TOF) value up to 2.51 s(-1) and the exchange current density reaches 4.34 mA cm(-2), indicating that the catalyst has better intrinsic catalytic activity. It is further proved by density functional theory (DFT) that the NiO surface is conducive to the adsorption of OH* in the Volmer step while the Ni is inclined to adsorb H*, which synergistically promotes the water-splitting reaction, thereby increasing the catalytic rate of HER. It is believed that this work will provide valuable contributions and inspirations toward the large-scale production of high-performance Ni-based electrocatalysts for HER.

Automated summary

In this study, a series of noble metal-doped ultra-small size (4 nm) M-Ni/NiO nanoparticles supported on CNT were designed using a solvent-free microwave reduction method. The catalysts showed high intrinsic activity and stability in the alkaline hydrogen evolution reaction (HER). The performance of Ir-Ni/NiO@CNT was particularly superior, with low overpotential, high turnover frequency, and exchange current density. Density functional theory further validated the catalyst's excellent performance.