Efficient hydrogen production from ammonia borane hydrolysis catalyzed by TiO2-supported RuCo catalysts

Hydrolysis of ammonia borane provides a reliable pathway for hydrogen production, while suitable catalysts are indispensable to make the hydrolysis reaction reach a considerable rate. In the present work, a series of TiO₂-supported RuCo catalysts have been fabricated by coprecipitation and subsequent reduction of Ru³⁺ and Co²⁺ on the surface of TiO₂ nanoparticles. Transmission electron microscopy and elemental mapping have verified the good distribution of metal species in the catalysts. The fabricated catalysts have shown excellent performance for catalyzing ammonia borane hydrolysis, especially in alkaline solutions with 0.5 M NaOH. For Ru₁Co₉/TiO₂ in which Ru/Co molar ratio is 1:9, the active energy of catalyzed ammonia borane hydrolysis is 33.25 kJ/mol, and a turnover frequency based on Ru as high as 1408 mol_H2/(mol_Ru·min) is obtained at 25 °C. Moreover, when different types of TiO₂ substrates are used, anatase TiO₂-supported catalysts show better catalytic activity than their counterparts with rutile TiO₂ as substrate or mixture of anatase and rutile TiO₂ as substrate.