Ultrasmall Ru Nanoclusters on Nitrogen-Enriched Hierarchically Porous Carbon Support as Remarkably Active Catalysts for Hydrolysis of Ammonia Borane

The development of the highly active nanocatalysts for effective hydrogen (H-2) production is of great significance for its practical applications in fuel cells. Herein, we reported a facile and scale-up synthetic methodology to grow in situ the remarkably active nanocatalysts of ultrasmall Ru nanoclusters on nitrogen (N)-enriched hierarchically macroporous-mesoporous carbon supports (Ru@hPCN). The resultant Ru@hPCN combines structural and chemical merits of well-dispersed 0.7-nm Ru nanoclusters, N-enriched functional surface and 3D hierarchically porous framework, all of which synergistically boost the catalytic performance toward the hydrolysis of ammonia-borane (AB). An unprecedented activity with a turnover frequency of 1850 min(-1) was achieved for the Ru@hPCN, which was 6.0 folds over that of commercialized Ru/C catalyst. Mechanism studies showed that the remarkably enhanced activity can be ascribed to the easier dissociation of electropositive H delta+ from H2O and the breakage of the B-N bonds as well as favorable mass transport in the Ru@hPCN during AB hydrolysis.