CeOx-modified RhNi nanoparticles grown on rGO as highly efficient catalysts for complete hydrogen generation from hydrazine borane and hydrazine

CeOx-modified RhNi nanoparticles (NPs) grown on reduced graphene oxide (rGO) (RhNi@CeOx/rGO) have been facilely prepared and successfully used as highly efficient catalysts for the rapid and complete hydrogen generation from aqueous solution of hydrazine borane (N2H4BH3) and hydrazine (N2H4), respectively. It was found that the CeOx-doped RhNi NPs with a size of around 3.5 nm were highly dispersed on rGO nanosheets. Among all the catalysts investigated, the optimized catalyst Rh0.8Ni0.2@CeOx/rGO with a CeOx content of 13.9 mol% exhibited the highest catalytic performance. The total turnover frequency (TOF) of Rh0.8Ni0.2@CeOx/rGO for hydrogen generation from N2H4BH3 reached 666.7 h(-1) (mol(H2) mol((Rh+Ni))(-1) h(-1)) at 323 K, which was among the highest of all the catalysts reported to date for this reaction, 10-fold higher than that of the benchmark catalyst Rh0.8Ni0.2, and 3-fold higher than that of Rh0.8Ni0.2 with a CeOx dopant (Rh0.8Ni0.2@CeOx) and a rGO support (Rh0.8Ni0.2/rGO). Even at room temperature, Rh0.8Ni0.2@CeOx/rGO can achieve a complete hydrogen generation from N2H4BH3 and N2H4 with a TOF value of 111.2 and 36.4 h(-1). This excellent catalytic performance might be attributed to the synergistic structural and electronic effects of the RhNi NPs, CeOx dopant, and rGO support. Moreover, this general method can be easily extended to facile synthesis of other metal/rGO systems with the doping of rare-earth oxides for more applications.