Atomically Precise Ni Nanoclusters for Improving Hydrogen Evolution Reaction Performance
Lipipuspa Sahoo, Aarti Devi, Amitava Patra
Abstract
The generation of green hydrogen via electrocatalytic water splitting is an emerging strategy in the prospect of developing future energy devices. Herein, we designed water-soluble atomically precise Ni nanoclusters (NCs) on MoSe 2 nanosheets (NSs) to enhance the hydrogen evolution reaction (HER) performance. The strong UV–vis absorption band and matrix-assisted laser deposition ionization (MALDI) time-of-flight mass spectra confirm the formation of Ni 7 NCs. The energy-dispersive X-ray spectroscopy mapping confirms the homogeneous distribution of Ni, Mo, and Se throughout the surface of the ultrathin NS. X-ray photoelectron spectroscopy study reveals the strong interfacial interaction between Ni NCs and MoSe 2 in the nanocomposite by substantial electron density transferring from Ni NCs to the MoSe 2 NSs. It is seen that the 5 wt % Ni/MoSe 2 composite structure exhibits the most notable HER efficiency with an overpotential of 170 mV vs reversible hydrogen electrode @ 10 mA/cm 2 which is significantly lower than that of bare MoSe 2 NSs (350 mV). The significantly lower Tafel slope of the Ni/MoSe 2 nanocomposite indicates that the HER kinetics of MoSe 2 is accelerated in the presence of Ni NCs. The charge-transfer resistance of the nanocomposite is significantly low compared to pristine MoSe 2, confirming the enhanced interfacial charge transfer. This work opens up further opportunities to design efficient and low-cost electrocatalysts for improving the HER performance by incorporating the advantages of both non-precious atomically precise metal NCs and transition-metal dichalcogenides in one system.