Ammonia borane-promoted surface reconstruction of copper oxide catalysts for efficient catalytic hydrogen production from hydrolysis

Abstract

During hydrogen production by hydrolysis of ammonia borane (AB), transition metal oxides act as active sites in the catalyst and can help to achieve rapid and large-scale release of hydrogen, but its catalytic mechanism is still under discussion. We developed a Cu₂O/CuO catalyst with precisely controlled valence states and identified the fundamental source of the catalytic activity of oxides. The successive changes in the Cu valence state content of Cu₂O/CuO resulted in a volcano-like trend of the catalyst activity, with the optimal hydrogen production rate from hydrolysis reaching 378.01 mL·g⁻¹·min⁻¹. The characterization of the catalysts after combined use revealed that AB prompted the catalyst surface to reconstruct during the catalytic process, forming a Cu/Cu₂O heterostructure. This study established, for the first time, the structure-activity relationship between the valence state of copper and its catalytic activity, providing a theoretical basis for the construction of copper-based catalysts for AB hydrolysis.