Lattice-Induced 2D Ti₃C₂T_x MXene and COF Supramolecular Nanohybrids for Electrocatalytic Water Splitting

Lattice-matching-guided supramolecular assembly offers a promising strategy for developing high-performance electrocatalysts for overall water splitting. This study innovatively proposes a novel supramolecular configuration design between Ti₃C₂T_x MXene nanosheets and a covalent organic framework. Through the in situ growth strategy, a vertically oriented supramolecular network structure is constructed. Because of the high lattice matching, the O atoms in COF can periodically coordinate with the Ti atoms on the surface of Ti₃C₂T_x MXene, forming matrix Ti-O-C bonds. These arrayed bonds can serve as efficient charge transfer "bridges", accelerating the interface charge transfer kinetics process. This unique architecture not only provides a path for the diffusion of electrolytes but also fully exposes catalytically active sites, which directly contribute to the enhancement of electrocatalytic performance. Specifically, it shows that the 10-Ti₃C₂T_x@COF supramolecular nanohybrid prepared exhibits excellent catalytic activity in both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). At a current density of 10 mA cm^-2, the HER overpotential is as low as 37 mV and only 284 mV for OER with impressive stability. Moreover, a low cell voltage of 1.558 V was achieved for the overall water splitting. This study provides a new material system and design inspiration for the development of high-performance overall water-splitting electrocatalysts through the supramolecular assembly strategy induced by lattice matching.