Oxidation‐Phosphorization Synthesis of Nitrogen‐Doped Biochar‐Supported CoP for Ammonia Borane Hydrolysis

An oxidation‐phosphorization route was adopted to prepare cobalt phosphide supported on nitrogen‐doped biochar (denoted as CoP/NBC) for ammonia borane hydrolysis. NBC (i.e., nitrogen‐doped biochar) was obtained by NH 4 Cl‐assisted pyrolysis of paulownia wood and used to disperse Co species. After in situ reduction, controlled oxidation, and low‐temperature phosphorization, CoP nanosheets were formed on the porous biochar support. The optimized CoP/NBC catalyst displayed a turnover frequency (TOF) of 47 mol H2 ∙mol Co −1 ∙min −1 at 303 K, and the catalyst had no significant loss of activity over five consecutive cycles. Structural characterization confirmed the formation of crystalline CoP and suggested interfacial electronic interactions between CoP and NBC. The porous N‐doped biochar support favored the dispersion of CoP and facilitated mass transfer, while phosphorization modified the electronic state of Co. These combined structural features contributed to the catalytic performance of CoP/NBC and provide a simple strategy for developing low‐cost non‐noble‐metal catalysts for hydrogen generation from ammonia borane.