Modulating composition and electronic structure enhance the catalytic performance of Co2MO4 (M=Fe, Ni, Cu) for NaBH4 hydrolysis

Abstract

The synergistic effect between metals is of great significance for improving the performance of materials, but the mechanism of synergistic catalytic of bimetallic has rarely been reported in the hydrolysis of sodium borohydride (NaBH4, SB). In this paper, a flower shaped Co2FeO4 catalyst with high catalytic performance was selected from a series of CoxM3-xO4 (M = Fe, Ni, Cu) catalysts by controlling the composition. Based on the results of XPS characterization and density functional theory (DFT) calculation, the influence of component control on catalytic performance was discussed and explained from the perspective of electronic structure, and the "valence band center" and "D-band center" descriptors were introduced into the SB hydrolysis reaction. The simulation analysis results showed that the synergistic effect between Co–Fe elements resulted in the smallest center shift of the D band, the smallest binding energy of the hydrolysis reaction, and the best promoting effect on the electronic structure, manifested as the best catalytic performance. The calculation results were consistent with the XPS characterization results and the experimental results of hydrolysis performance testing, revealing the principle of bimetallic synergistic effect on catalytic performance.