Enhanced hydrogen storage performance of reduced graphene oxide hybrids with nickel or its metallic mixtures based on spillover mechanism

•Reduced graphene oxide (rGO) was decorated with metallic nanoparticles.•Ni/rGO, Ni/Pd/rGO and Ni/Ag/Pd/rGO hybrids were synthesized.•High hydrogen adsorption capability was observed at ambient environment.•Enhancement on H2 storage performance was attributed to the spillover mechanism.•Composition of the metallic NPs affects H2 adsorption/desorption reversibility.

In this work, as a fascinating 2-dimensional carbon material, reduced graphene oxide (rGO) has been decorated with Ni, Ni/Pd, and Ni/Ag/Pd nanoparticles on its surface to enhance its hydrogen storage performance based on the spillover mechanism. First, graphene oxide (GO) was fabricated from graphite by a modified Hummer method. Next the GO was dispersed in water and mixed with nickel chloride, palladium chloride, and/or silver nitrate to synthesize parental Ni(OH)2/GO, Ni(OH)2/Pd(OH)2/GO, and Ni(OH)2/Pd(OH)2/AgOH/GO hybrids through hydrothermal treatment with HMTA as a capping and precipitation agent. After in situ reduction of these parental hybrids with hydrogen flow and heat treatment at 350 °C, nanostructured Ni/rGO, Ni/Pd/rGO, and Ni/Ag/Pd/rGO hybrids were obtained. These Ni (Ni/Pd, or Ni/Ag/Pd)/rGO hybrids show great potential in hydrogen storage at ambient environment, as measured at room temperature (293.15 K) and 800 mmHg, 0.007, 0.13, and 0.055 wt% hydrogen adsorption capacity was obtained from the Ni/rGO, Ni/Pd/rGO, and Ni/Ag/Pd/rGO hybrids, respectively.

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