Highly Active and Robust Catalyst: Co 2 B-Fe 2 B Heterostructural Nanosheets with Abundant Defects for Hydrogen Production.

A high-performance and reusable nonnoble metal catalyst for catalyzing sodium borohydride (NaBH 4 ) hydrolysis to generate H 2 is heralded as a nuclear material for the fast-growing hydrogen economy. Boron vacancy serves as a flexible defect site that can effectively regulate the catalytic hydrolysis performance. Herein, we construct a uniformly dispersed and boron vacancy-rich nonnoble metal Co 2 B-Fe 2 B catalyst via the hard template method. The optimized Co 2 B-Fe 2 B exhibits superior performance toward NaBH 4 hydrolysis, with a high hydrogen generation rate (5315.8 mL min -1 g catalyst -1 ), relatively low activation energy (35.4 kJ mol -1 ), and remarkable cycling stability, outperforming the majority of reported catalysts. Studies have shown that electron transfer from Fe 2 B to Co 2 B, as well as abundant boron defects, can effectively modulate the charge carrier concentration of Co 2 B-Fe 2 B catalysts. Density functional theory calculations confirm that the outer electron cloud density of Co 2 B is higher than that of Fe 2 B, among which Co 2 B with high electron cloud density can selectively adsorb BH 4 - ions, while the electron-deficient Fe 2 B is favorable for capturing H 2 O molecules, therefore synergistically promoting the catalytic NaBH 4 hydrolysis to produce H 2 .