Synergistic interface between metal Cu nanoparticles and CoO for highly efficient hydrogen production from ammonia borane

Abstract

The development of efficient non-noble metal catalysts for the dehydrogenation of hydrogen (H₂) storage materials is highly desirable to enable the global production and storage of H₂ energy. In this study, Cu_x–(CoO)_1−x/TiO₂ catalysts with a Cu–CoO interface supported on TiO₂ are shown to exhibit high catalytic efficiency for ammonia borane (NH₃BH₃) hydrolysis to generate H₂. The best catalytic activity was observed for a catalyst with a Cu : Co molar ratio of 1 : 1. The highest dehydrogenation turnover frequency (TOF) of 104.0 mol_H2 mol_metal⁻¹ min⁻¹ was observed in 0.2 M NaOH at room temperature, surpassing most of the TOFs reported for non-noble catalysts for NH₃BH₃ hydrolysis. Detailed characterisation of the catalysts revealed electronic interactions at the Cu–CoO heterostructured interface of the catalysts. This interface provides bifunctional synergetic sites for H₂ generation, where activation and adsorption of NH₃BH₃ and H₂O are accelerated on the surface of Cu and CoO, respectively. This study details an effective method of rationally designing non-noble metal catalysts for H₂ generation via a metal and transition-metal oxide interface.