Study on the influence factors of Pt-based catalyst on dehydrogen performance of ammonia borane hydrolysis-Which is more important, geometric effects or electronic effects?

Abstract

The basic catalytic properties of catalysts are largely determined by their geometric and electronic structures. However, the geometric and electronic interference between the active atoms and their neighbors makes it difficult to determine the extent of the effects of geometric and electronic effects on the catalytic activity. In this paper, Pt-based (Fe, Co, Ni, Cu and Zn) alloy nanoparticles (NPs) were prepared by a one-step reduction method. Through X-ray diffraction (XRD) analysis, high-resolution transmission electron microscopy (HRTEM) analysis and X-ray photoelectron spectroscopy (XPS) analysis, the superior lattice compression effect of Pt3Cu was found. It has great influence on catalytic performance. However, with the increase of Cu content, electron transfer increases, and the effect of electron effect is greater than the effect of lattice compression. Among them, Pt3Cu has the best performance as the content of Pt is high, which is controlled by geometric effects. When the content of Pt is few, the catalytic performance of PtNi3 is the best, showing the results regulated by electronic effects. The d-band center and Bader charge are determined by DFT calculation, and the experimental results are verified. The results show that the position of the d-band center is in a volcanic trend with HER properties. Pt3Cu has a suitable d-band central position, which affects the adsorption and desorption behavior of H2O molecules in the hydrolysis reaction, thus affecting its catalytic performance. These results provide new insights into the relationship between the geometric and electronic effects of catalysts and their catalytic ammonia borane hydrolysis activity.