Efficient Synthesis of Ag–Co3O4 Nanocatalysts for Hydrogen Evolution from Ammonia Borane Hydrolysis

It is of great significance to prepare high-performance non-precious metal catalysts for hydrogen evolution from the ammonia borane (NH3BH3, AB). Here, a series of cost-effective and high-performing Ag–Co3O4 nanocatalysts were prepared using AgNO3 and Co(NO3)2⋅6H2O as precursors. The influence of varying doping amounts of Ag atoms (10 mg AgNO3, 20 mg AgNO3, 40 mg AgNO3, 60 mg AgNO3) and heat treatment temperatures (300, 400, 500, 600°C) on the catalytic activity of the Ag–Co3O4 nanocatalysts for AB hydrolysis was investigated. The obtained results reveal that the Ag–Co3O4 nanocatalysts exhibit a well-defined nano-flower morphology with homogeneous distribution of silver atoms over the Co3O4 surface. Moreover, an evident electronic synergy between Ag and Co3O4 is observed. The 20-Ag–Co-500 catalyst (doped with 20 mg of AgNO3 and subjected to heat treatment at 500°C) exhibits exceptional catalytic activity towards AB hydrolysis (TOF = 348.03 $${\text{mo}}{{{\text{l}}}_{{{{{\text{H}}}_{{\text{2}}}}}}}$$ min–1 $${\text{mol}}_{{{\text{Ag}}}}^{{ - 1}}$$ and Ea = 56.20 kJ/mol).