In-situ doping-induced lattice strain of NiCoP/S nanocrystals for robust wide pH hydrogen evolution electrocatalysis and supercapacitor

Developing high-efficiency multifunctional nanomaterials is promising for wide pH hydrogen evolution reaction (HER) and energy storage but still challenging. Herein, a novel in-situ doping-induced lattice strain strategy of NiCoP/S nanocrystals (NCs) was proposed through using seed crystal conversion approach with NiCo2S4 spinel as precursor. The small amount of S atoms in NiCoP/S NCs perturbed the local electronic structure, leading to the atomic position shift of the nearest neighbor in the protocell and the nanoscale lattice strain, which optimized the H* adsorption free energy and activated H2O mole-cules, resulting the dramatically elevated HER performance within a wide pH range. Especially, the NiCoP/S NCs displayed better HER electrocatalytic activity than comical 20% Pt/C at high current density in 1 M KOH and natural seawater: it only needed 266 mV vs. reversible hydrogen electrode (RHE) and 660 mV vs. RHE to arrive the current density of 350 mA cm(-2) in 1 M KOH and natural seawater, indicating the application prospect for industrial high current. Besides, NiCoP/S NCs also displayed excellent super-capacitor performance: it showed high specific capacity of 2229.9 F g(-1) at 1 A g(-1) and energy density of 87.49 Wh kg(-1), when assembled into an all-solid-state flexible device, exceeding performance of most transition metal phosphides. This work provides new insights into the regulation in electronic structure and lattice strain for electrocatalytic and energy storage applications. (c) 2022 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

In this study, NiCoP/S nanocrystals were synthesized using a novel method and exhibited excellent hydrogen evolution reaction (HER) and supercapacitor performance in a wide pH range. The findings provide new insights into the modulation of electronic structure and lattice strain for electrocatalytic and energy storage applications.