Novel Strain Engineering Combined with a Microscopic Pore Synergistic Modulated Strategy for Designing Lattice Tensile-Strained Porous VC-MXene for High-Performance Overall Water Splitting.

Transition metal carbon/nitride (MXene) holds immense potential as an innovative electrocatalyst for enhancing the overall water splitting properties. Nevertheless, the re-stacking nature induced by van der Waals force remains a significant challenge. In this work, the lattice tensile-strained porous VC-MXene (named as TS-P-VC) is successfully constructed via the rapid spray freezing method and the following hydrothermal treatment. Besides, the influence of lattice strain degree and microscopic pores on the catalytic ability is reviewed and explored systematically. The lattice tensile strain within VC-MXene could widen the interlayer spacing and accelerate the ion transfer. The microscopic pores could change the ion transmission path and shorten the migration distance. As a consequence, the obtained TS-P-VC shows extraordinary hydrogen evolution reaction and oxygen evolution reaction activity with the overpotential of 154 and 269 mV, respectively, at the current density of 10 mA/cm, which is quite remarkable compared to the MXene-based electrocatalysts. Moreover, the overall water splitting device assembled using TS-P-VC as both anode and cathode demonstrates a low cell voltage requirement of 1.57 V to obtain 10 mA/cm. Overall, the implementation of this work could offer an exciting avenue to overcome the re-stacking issue of VC-MXene, affording a high-efficiency electrocatalyst with superior catalytic activity and desirable reaction kinetics.