Supramolecular Anchoring Strategy for Facile Production of Ruthenium Nanoparticles Embedded in N-Doped Mesoporous Carbon Nanospheres for Efficient Hydrogen Generation

Because of the favorable mass transport and increased available active sites, the rational design and preparation of porous carbon structures are essential but still challenging. Herein, a novel and facile supramolecular anchoring strategy was developed to achieve the embedding of ruthenium (Ru) nanoparticles in N-doped mesoporous carbon nanospheres through pyrolyzing the precursor formed by coordination assembly between metal ions and zinc gluconate (G(Zn)). Featuring rich hydroxyl groups, the G(Zn) can effectively chelate Ru3+ via metal-oxygen bonds to form 3D supramolecular nanospheres, and meanwhile, mesopores in carbon nanospheres were expanded after subsequent pyrolysis thanks to the volatilization of zincic species at high temperature. As a demonstration, the best-performing catalyst displayed extraordinary activity for the hydrogen evolution reaction (HER) with a small overpotential of 43 mV versus reversible hydrogen electrode (vs RHE) at 10 mA/cm2 and a Tafel slope of 39 mV/dec, which was superior to that of commercial Pt/C in alkaline medium. Theoretical calculations revealed that the catalytic activity was significantly promoted by the strong electronic coupling between Ru nanoparticles and N-doped porous carbon, which increased the electron transfer capability and facilitated the adsorption and dissociation of H2O to realize an efficient HER.