Steering the electronic communication between Al/Ru bimetallic clusters in metal–organic framework composites for accelerating hydrogen evolution kinetics

Abstract

Synergistically modulating electron distribution between metal nodes in metal–organic frameworks (MOFs) is an effective strategy to improve the electrocatalytic performance of MOFs. Herein, a special bimetallic MOF composite (Al_0.35/Ru_0.15-TCPP-CNTs) was constructed by introducing highly dispersed Ru and Al co-existing in the MOF metal clusters and combining them with conductive carboxylic multi-walled carbon nanotubes (CNTs). Notably, the catalyst exhibited excellent hydrogen evolution reaction (HER) performance, with an overpotential of as low as 32 mV at a current density of 10 mA cm⁻² in acidic media, comparable to commercial Pt/C. Experimental results and density functional theory (DFT) calculations proved that a reasonable proportion of Al/Ru bimetallic clusters in MOFs and the loaded CNTs induced charge redistribution and cooperative electronic coupling, which not only optimized the adsorption energy of H intermediates (ΔG_H*) and produced a possible hydrogen spillover effect, but also increased the specific surface area and facilitated electron/mass transfer. This work may provide an improved method and research idea for the study of MOF electrocatalysts at the atomic level.