Chrysanthemum-like CoP/Co3O4 heterostructures for efficient hydrogen generation from ammonia borane hydrolysis

Cost-effective non-noble metal CoP/Co 3 O 4 catalyst for AB hydrolysis. • TOF of 9.8 min -1 and Ea of 51.87 kJ/mol for AB hydrolysis over CoP/Co 3 O 4 . • Reaction kinetics: pseudo-first-order in catalyst, pseudo-zero-order in AB. Hydrogen production via ammonia borane (AB) hydrolysis represents a promising pathway for advancing the hydrogen economy. Developing cost-effective, highly active catalysts for this reaction is imperative, yet remains a significant challenge. Herein, a precursor of chrysanthemum-like Co 3 O 4 was synthesized from cobalt chloride hexahydrate via hydrothermal treatment followed by calcination in air. Then,non-noble metal CoP/Co 3 O 4 cocatalyst was fabricated through a simple solid phosphidation at 300 °C using chrysanthemum-like Co 3 O 4 and NaH 2 PO 2 . The as-prepared samples were comprehensively analyzed to determine their composition, structure, morphology using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The catalytic performance of the CoP/Co 3 O 4 composite toward hydrogen evolution from AB hydrolysis was systematically evaluated. The hydrogen evolution rate and turnover frequency (TOF) of the CoP/Co 3 O 4 -catalyzed hydrolysis of AB were further evaluated under various conditions. The results indicate that at a phosphidation ratio of m (Co 3 O 4 ) / m (NaH 2 PO 2 ) = 0.1, the CoP/Co 3 O 4 exhibits superior catalytic activity toward AB hydrolysis, achieving a TOF of 9.8 min -1 and an activation energy determined to be 51.87 kJ·mol −1 . The reaction kinetics followed pseudo-first-order dependence on catalyst concentration and pseudo-zero-order dependence on AB concentration. The remarkable performance of CoP/Co 3 O 4 can be attributed to its chrysanthemum-like morphology, which provides abundant accessible active sites. Given its low cost, this catalyst represents a promising, non-precious alternative for hydrogen generation. Download: Download high-res image (226KB) Download: Download full-size image