Oxygen modified CoP₂ supported palladium nanoparticles as highly efficient catalyst for hydrolysis of ammonia borane

Ammonia borane (AB) is regarded as a promising chemical hydrogen-storage material due to its high hydrogen content, non-toxicity, and long-term stability under ambient temperature. However, constructing advanced catalysts to further promote the hydrogen production still remains a challenge for the hydrolysis of AB. Herein, we report a novel oxygen modified CoP₂ (O-CoP₂) material with dispersed palladium nanoparticles (Pd NPs) as a highly efficient and sustainable catalyst for AB hydrolysis. The modification of oxygen could optimize the catalytic synergy effect between CoP₂ and Pd NPs, achieving enhanced catalytic activity with a turnover frequency (TOF) number of 532 min⁻¹ and an activation energy (E_a) value of 16.79 kJ·mol⁻¹. Meanwhile, reaction kinetic experiments prove that the activation of water is the rate-determining step (RDS). The water activation mechanism is revealed by quasi in-situ X-ray photoelectron spectroscopy (XPS) and in-situ X-ray absorption fine structure (XAFS) measurements. The activation of water leads to the production of –H and –OH groups, which are further adsorbed on the oxygen atoms in P–O bond and Pd atoms, respectively. In addition, density functional theory (DFT) calculations indicate that the introduced oxygen facilitates the adsorption and activation of water molecules. This novel modulation strategy successfully sheds new light on the development of advanced catalysts for hydrolysis of AB and beyond.