Ultrafine Ni−MoOx Nanoparticles Anchored on Nitrogen‐Doped Carbon Nanosheets: A Highly Efficient Noble‐Metal‐Free Catalyst for Ammonia Borane Hydrolysis

Abstract

AbstractThe development of low‐cost and high‐efficiency catalysts for the hydrolytic dehydrogenation of ammonia borane (AB, NH3BH3) is still a challenging technology. Herein, ultrafine MoOx‐doped Ni nanoparticles (~3.0 nm) were anchored on g‐C3N4@glucose‐derived nitrogen‐doped carbon nanosheets via a phosphate‐mediated method. The strong adsorption of phosphate‐mediated nitrogen‐doped carbon nanosheets (PNCS) for metal ions is a key factor for the preparation of ultrasmall Ni nanoparticles (NPs). Notably, the alkaline environment formed by the reduction of metal ions removes the phosphate from the PNCS surface to generate P‐free (P)NCS so that the phosphate does not participate in the subsequent catalytic reaction. The synthesized Ni−MoOx/(P)NCS catalysts exhibited outstanding catalytic properties for the hydrolysis of AB, with a high turnover frequency (TOF) value of up to 85.7 min−1, comparable to the most efficient noble‐metal‐free catalysts and commercial Pt/C catalyst ever reported for catalytic hydrogen production from AB hydrolysis. The superior performance of Ni−MoOx/(P)NCS can be ascribed to its well‐dispersed ultrafine metal NPs, abundant surface basic sites, and electron‐rich nickel species induced by strong electronic interactions between Ni−MoOx and (P)NCS. The strategy of combining multiple modification measures adopted in this study provides new insights into the development of economical and high‐efficiency noble‐metal‐free catalysts for energy catalysis applications.