Stereoassembly of ultrasmall Rh-decorated zeolite imidazolate framework–MXene heterostructures for boosted methanol oxidation reaction

Abstract

Due to the diminishing energy resources and environmental pollution issues, direct methanol fuel cells (DMFCs) have gained a high profile in recent decades as a green energy generator, thereby promoting the exploitation of the cost-effective and high-performance anode catalysts for the methanol oxidation reaction. Herein, we present the rational design and controllable fabrication of ultrasmall Rh nanocrystal-decorated heterostructures from Zn-based zeolites imidazolate frameworks (ZIFs) and Ti₃C₂T_x MXene nanosheets (Rh/ZIF–MX) via a bottom-up stereoassembly strategy. The incorporation of ZIFs creates abundant pore channels and anchoring sites for Rh immobilization, while the presence of the Ti₃C₂T_x nanosheets affords strong electronic interactions with the Rh atoms and simultaneously guarantees prominent electrical conductivity. Due to this synergistic effect, the harvested Rh/ZIF–MX nanoarchitectures exhibited distinct electrocatalytic superiorities towards methanol oxidation, including a large electrochemically active surface area of 161.5 m² g⁻¹, a high mass activity of 2955.1 mA mg⁻¹ and exceptional long-term stability, which are evidently more competitive than those of traditional Rh catalysts directly supported on carbon black, carbon nanotubes, graphene, and MXene matrices.