Ti₃C₂T_x-Based Three-Dimensional Hydrogel by a Graphene Oxide-Assisted Self-Convergence Process for Enhanced Photoredox Catalysis

Assembly of two-dimensional (2D) layered structures into three-dimensional (3D) macroscopic hydrogel has been an enduring attracting research theme. However, the anisotropic intersheet cross-linking to form Ti3C2Tx MXene-based hydrogel remains intrinsically challenging because of the superior hydrophilic nature of 2D Ti3C2Tx. Herein, Ti3C2Tx MXene is ingeniously assembled into the 3D macroscopic hydrogel under mild conditions by a graphene oxide (GO)-assisted self-convergence process. During the process, GO is reduced to reduced graphene oxide (RGO) by virtue of the reduction ability of Ti3C2Tx, leading to the partial removal of hydrophilic oxygen-containing groups and an increase of the hydrophobicity and the π-conjugated structures of RGO, which enables the assembly of RGO into a 3D RGO framework. Simultaneously, Ti3C2Tx is self-converged to be incorporated into the RGO framework by intimate interfacial interactions, thereby generating Ti3C2Tx-based hydrogel. The hydrogel with interconnected porous structure holds great potential as a promising material platform for photoredox catalysis. With the incorporation of Eosin Y photosensitizer, the functional Ti3C2Tx-based hydrogel exhibits enhanced photoactivity compared to the powder counterpart and features easy operability. This work enriches the rational utilization of GO/MXene colloid chemistry to design Ti3C2Tx MXene-based hydrogels with improved overall efficacy in practical applications.