The mechanism and challenges of cobalt-boron-based catalysts in the hydrolysis of sodium borohydride

Abstract

Among boron compounds, NaBH₄ has emerged as a prominent candidate for hydrogen energy sources owing to its environmentally friendly characteristics and a high hydrogen content of up to 10.6 wt%. However, the hydrolysis of NaBH₄ on catalyst surfaces is an exothermic reaction, necessitating catalysts with high stability and structural strength for efficient hydrolysis. Previous studies have demonstrated that Co–B alloys exhibit favorable catalytic activity for NaBH₄ hydrolysis. In this review, we summarize the synthetic methods, catalytic characteristics, applications, and reaction mechanisms of Co–B-based catalysts for further investigation. The report provides an overview of the relationships between the material structures, properties, and applications of Co–B-based catalysts. Firstly, we introduce the hydrogen generation mechanism of NaBH₄, followed by a discussion on recent progress in the synthetic methods and catalytic properties of unsupported and supported Co–B-based catalysts. Finally, we summarize details related to Co–B-based catalysts with supporting structures. Notably, among supported structures, exceptional hydrogen generation ability is exhibited by a Co–B/BFS catalyst at 70 410 mL min⁻¹ g⁻¹, while among unsupported structures, the highest HG value is observed with Co–Mn–B at 35 000 mL min⁻¹ g⁻¹. Lastly, we provide a brief outlook on future development prospects for Co–B-based catalysts in NaBH₄ applications.