Tailoring the interfacial electron redistribution of ball-in-ball structured CuO-Co3O4 nanocomposites for synergistic enhancement in hydrolytic dehydrogenation of ammonia borane

Abstract

Construction of high-efficiency and affordable catalysts for hydrogen production from hydrolysis of ammonia borane is highly desirable, but significant challenges still exist. In this study, a series of ball-in-ball hollow structured CuO-Co3O4 nanocomposites with varied Cu/Co molar ratio were constructed via simple solvothermal method combined with a post-calcination. The CuO-Co3O4 composite featuring a Cu/Co molar ratio of 1: 2 displayed the highest catalytic efficiency, achieving a turnover frequency (TOF) value of 25.0 molH2 molcat.−1 min−1 for AB hydrolysis. An evident synergistic enhancement in catalytic activity was confirmed between CuO and Co3O4. Experimental and theoretical researches uncovered that the enhancement of activity is originated from the electron transfer between Cu and Co ingredients, which is beneficial for the adsorption and activation of H2O and ammonia borane. In addition, the DFT calculations results revealed that the actual active sites for AB hydrolysis in CuO-Co3O4 composite catalyst is the Co site. These findings should provide some insightful recommendations for designing robust and cost-effective composite catalysts for the hydrolytic dehydrogenation of ammonia borane.