Activated carbon derived from tea waste: A promising supporting material for metal nanoparticles used as catalysts in hydrolysis of ammonia borane

Abstract

Activated carbons with high porosity and high surface area are promising materials to be used in wide-range applications. They can easily be prepared from various biomass source following by simple and reproducible activation and carbonization steps. In this study, the woody part of tea which is highly available tea waste after the harvesting of tea leaves is considered as the precursor of highly porous activated carbon. In fact, activated carbon with well-ordered porous structure (micropore area = 1614.3 m2 g−1, micropore volume = 1.13 cm3 g−1) and high surface area (2559 m2 g−1) was achieved using this tea waste. The obtained activated carbon was used to support cobalt, nickel and copper nanoparticles which were used as catalysts in H2 generation from aqueous ammonia borane. The results reveal that Co nanoparticles with an average particle size of 3.18 nm on activated carbon provide higher activity (TOF = 7.5 min−1) as compared to nickel (TOF = 4.8 min−1) and copper nanoparticles in this reaction. Herein, we report also the kinetic studies including the effect of temperature, metal concentration and metal loading on the catalytic activity in hydrolysis of ammonia borane.