RunPd1 fully-exposed clusters for solvent-free hydrogenation of toluene toward hydrogen storage.

Liquid organic hydrogen carriers are promising for large-scale and long-distance hydrogen storage and transportation. Considering that renewable hydrogen sources are often decentralized and intermittent, designing a catalyst that is simultaneously cost-effective, room-temperature compatible, and environmentally-friendly remains a significant challenge. This contribution introduce a single Pd1 assisted fully exposed Ru clusters supported on defective graphene/nanodiamonds hybrid support (RunPd1/ND@G) catalyzing efficient toluene hydrogenation under solvent-free conditions, in which the conversion of toluene could achieve 100% even at room temperature. Remarkably, RunPd1 fully-exposed cluster delivers an exceptionally high turnover frequency of 35199.5 h-1 at the absence of solvent, which is 5.9 times higher than that of the monometallic Ru/ND@G catalyst. The catalyst exhibits maximized atomic efficiency, excellent recyclability and reaction scalability. Combing with theoretical calculations, it is revealed that Pd1 assisted fully-exposed Ru cluster catalysts promoted H2 activation and C-H formation as well as improved reactant (product) adsorption (desorption), which all contribute to the superior activity of RunPd1 fully-exposed clusters. This work offers a practical strategy for efficient hydrogen energy utilization under solvent-free conditions.