The “electric-dipole” effect of Pt–Ni for enhanced catalytic dehydrogenation of ammonia borane

In this work, we prepared the PtNi alloy nanoparticles on Al2O3 (Al2O3–PtNi) via a simple wet-grinding method followed by a thermal reduction process. The as-prepared Al2O3–PtNi displayed a higher TOF of 426.84 molH2 (molPt·min)−1 toward the dehydrogenation of AB (ammonia borane) than Al2O3–Pt and Al2O3–Ni. Based on the theoretical calculations, an “electric-dipole” effect generated by the neighboring Pt–Ni atoms was found to facilitate the catalytic dehydrogenation process of ammonia borane (AB). The external electric field produced by the Pt–Ni dipole can elongate the B–H bond and increase the negative charges of H atoms on the BH3 group, which helps to activate the B–H bond in the AB molecule, and thus enhances the kinetic process of catalysis. [Display omitted] •An electric dipole is formed between the neighboring Pt and Ni atom.•The Pt–Ni dipole generates a local external electric field.•The electric field increases negative charges in H atoms on BH3 group and B–H length.•The electric field helps to improve the interaction between AB molecule and Pt atom.•The electric dipole effect leads to the higher catalytic activity of Al2O3@PtNi.