The sluggish kinetics of Volmer step in the alkaline hydrogen evolution results in large energy consumption. The challenge that has yet well resolved is to control the water adsorption and dissociation. Here, we develop biaxially strained MoSe₂ three dimensional nanoshells that exhibit enhanced catalytic performance with a low overpotential of 58.2 mV at 10 mA cm⁻² in base, and long-term stable activity in membrane-electrode-assembly based electrolyser at 1 A cm⁻². Compared to the flat and uniaxial-strained MoSe₂, we establish that the stably adsorbed OH engineer on biaxially strained MoSe₂ changes the water adsorption configuration from O-down on Mo to O-horizontal on OH* via stronger hydrogen bonds. The favorable water dissociation on 3-coordinated Mo sites and hydrogen adsorption on 4-coordinated Mo sites constitute a tandem electrolysis, resulting in thermodynamically favorable hydrogen evolution. This work deepens our understanding to the impact of strain dimensions on water dissociation and inspires the design of nanostructured catalysts for accelerating the rate-determining step in multi-electron reactions.

The structure-performance relationship for single atom catalysts has remained unclear due to the averaged coordination information obtained from most single-atom catalysts. Periodic array of single atoms may provide a platform to tackle this inaccuracy. Here, we develop a data-driven approach by incorporating high-throughput density functional theory computations and machine learning to screen candidates based on a library of 1248 sites from single atoms array anchored on biaxial-strained transition metal dichalcogenides. Our screening results in Au atom anchored on biaxial-strained MoSe₂ surface via Au-Se₃ bonds. Machine learning analysis identifies four key structural features by classifying the ΔG_H* data. We show that the average band center of the adsorption sites can be a predictor for hydrogen adsorption energy. This prediction is validated by experiments which show single-atom Au array anchored on biaxial-strained MoSe₂ archives 1000 hour-stability at 800 mA cm^-2 towards acidic hydrogen evolution. Moreover, active hotspot consisting of Au atoms array and the neighboring Se atoms is unraveled for enhanced activity.

Developing low-cost, environmentally friendly and efficient non-precious metal electrocatalysts as alternatives to noble metals for the hydrogen evolution reaction (HER) is highly essential for the sustainable advancement of green hydrogen energy. Herein, a novel heterostructured Ni₃P/Ni nanoparticle anchored in nitrogen-doped mesoporous carbon nanofibers (Ni₃P/Ni@N-CNFs) is prepared by a facile solid-phase calcination protocol. The results demonstrated that benefiting from the intensive electronic coupling effect at the interface of the Ni₃P/Ni heterostructure, the electron configuration of the Ni active site is optimized and thus the favorable HER activity. Furthermore, the N-doped carbon nanofiber scaffold with an extensive mesoporous structure endows Ni₃P/Ni@N-CNFs with abundant electrochemically active sites together with excellent conductivity and stability, contributing to fast electron/mass transport. As expected, the resultant Ni₃P/Ni@N-CNF electrocatalyst exhibited exceptional HER catalytic properties under universal pH conditions, driving a current density of 10 mA cm⁻² at pretty low overpotentials of 121 mV, 145 mV and 187 mV in acidic, basic and neutral solutions, respectively, and retaining the catalytic stability for over 60 h. This intriguing work represents a fresh perspective for designing and exploiting highly advanced phosphide electrocatalysts for green hydrogen fuel production.