Abstract
In the ammonia borane(AB)hydrolysis reaction,overcoming the weak activation of H2O by metal catalysts can be achieved by introducing transition metal oxides(TMOs)for catalyst active-sites design.Herein,we uncovered that oxygen vacancy(Vo)-attired Cu/Cu_(0.76)CO_(2.24)O4 dual-active-sites catalysts significantly increase the hydrogen production rate of AB hydrolysis.The turnover frequency of Cu/Cu_(0.76)CO_(2.24)O4-VO dehydrogenation in 0.10 M NaOH can reach 50.33 mol_(H2)/(mol_(cat)·min),which is 45.9 times that of metal Cu.By means of a joint experimental and computational study,the VO defects promote the formation of electron-rich surface of Cu/Cu_(0.76)CO_(2.24)O4,and the Cu also enriches the surface electrons due to the strong interaction with TMOs,which enhances the activation of O-H and B-H bonds,respectively,and significantly accelerates the rate-determining step of the reaction.This work demonstrates the important role of constructive defects in regulating surface electrons of dual-active-sites catalysts on the performance enhancement and provides a broader idea for the design of excellent AB hydrolysis catalysts.
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