Interface engineering of three-phase NiO-CuO/Fe3O4 heterostructured catalyst for quick hydrogen release from ammonia borane methanolysis

Catalytic methanolysis of ammonia borane represents a promising technology for in situ hydrogen production. However, the widespread application of this technology is constrained by the prohibitive cost associated with noble metal catalysts. Consequently, the development of cost-effective and robust is essential for commercial scaling of this technology. In this study, a series of NiO-CuO/Fe₃O₄ catalyst with three-phase interfaces for ammonia borane methanolysis were fabricated by supporting NiO-CuO with Fe₃O₄. It was demonstrated that the Fe₃O₄ support in the catalyst could not only modulate the electronic structure of catalyst but also and confer magnetic characteristics upon it. The catalyst bearing a Ni/Cu molar ratio of 2:2 achieved a turnover frequency (TOF) of 13.5 min^-1 in ammonia borane methanolysis, along with long-term stability. Furthermore, magnetic characterization confirmed the catalyst’s ferromagnetic properties with a coercivity of 51.8 Oe, facilitating the magnetic separation of the catalyst under an external magnetic field. Through various exhaustive characterizations, it was revealed that abundant interfacial positively charged Ni sites and negatively charged Cu sites in NiO-CuO/Fe₃O₄ catalyst could activate methanol and ammonia borane, respectively, thus promoting the hydrogen production efficiently. Considering the excellent activity and recyclability of NiO-CuO/Fe₃O₄, it is anticipated to gain widespread applications in the industrial production of hydrogen from ammonia borane methanolysis.