An in-situ strategy for tuning tensile strain to enhance hydrogen electrocatalysis on nickel-based catalysts

New setup monitors catalytic activity in-situ under tensile stress on metal foils. • Tensile stress shifts Ni d-band center up, lowering water dissociation barrier, boosting HER. • Heterostructure enables simple tensile strain tuning in Ni to enhance catalysis. Nickel is a widely used, non-precious metal electrocatalyst in the hydrogen evolution reaction (HER) and the hydrogen oxidation reaction (HOR). Herein, we developed a unique in-situ setup to investigate and monitor the impact of strain on the electrocatalytic properties of nickel metal by examining the HER activity of a macroscopically strained nickel sheet. The application of strain effectively optimizes the electronic structure of Ni, facilitating the accelerated dissociation of water and, consequently, enhancing the catalytic reaction. Furthermore, we synthesized Ni/Ni 0.2 Mo 0.8 N catalysts with heterostructures and induced microscopic stress on the crystal plane of Ni through these heterojunctions. The resulting Ni/Ni 0.2 Mo 0.8 N exhibited remarkable HER and HOR activity in alkaline solutions. A series of characterizations confirmed the presence of strain, and the activity of Ni was found to increase with the degree of strain. These findings introduce a novel approach for optimizing Ni-based materials in hydrogen catalysis and beyond.