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 molH2/(molRu·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.