Strong Electronic Metal-Support Interaction Augments Hydrogen Evolution over hcp-Ni/In₂O₃ with Ultrasound-Assisting Dehydrogenation of Ammonia Borane

Rational design of highly efficientcatalysts for thedehydrogenationof ammonia borane (AB) to produce hydrogen is still challenging. Thesize and shape effects of catalysts on the performance have been welldocumented in the past decades. Nevertheless, there is still muchspace for study on the crystal structure-dependent catalytic performance.Herein, In2O3-supported hexagonal-close-packed(hcp) Ni (hcp-Ni/In2O3) has been prepared viaimpregnation of corresponding nanoparticles onto In2O3. The stronger electronic metal-support interactionin hcp-Ni/In2O3 than in fcc-Ni/In2O3 endows it with high capacity to activate AB molecules.It exhibits excellent hydrogen evolution activity from catalytic dehydrogenationof AB with a rate of 7.5 mol(H2) mol(-1) (Ni) min(-1), which is 1.7 times that of thesupported fcc sample. The systematic experiments and DFT calculationsdemonstrate that the hcp catalyst possesses stronger hydrophilicityand lower activation energy for the dissociation of H(2)Othan the fcc counterpart. Moreover, the assistance with sonicationenhances the process of mass and heat transfer and accelerates thereaction. This work provides a new way for the achievement of efficientmetastable catalytic systems and promotes the construction of advanceddevices toward various applications.