Carbon nitride supported Ni0.5Co0.5O nanoparticles with strong interfacial interaction to enhance the hydrolysis of ammonia borane

Ammonia borane (AB) is an ideal hydrogen-storage material for fuel cells but its application has been strongly limited by using rare noble-metal-based catalysts. Here we have prepared a hybrid material of Ni0.5Co0.5O nanoparticles on nitric-acid treated carbon nitride (NCN) for the hydrolysis of AB. The Ni0.5Co0.5O-NCN catalyst achieves a high total turnover frequency (TOF) value of 76.1 (H-2)mol per (Cat-metal) mol min in pure water at room temperature, with a good stability by keeping 83.2% activity after 6 runs. The TOF is comparable to the best values ever reported for noble-metal-free catalysts without extra conditions such as light illumination or a strong alkaline environment. Synchrotron radiation based X-ray absorption spectroscopy reveals that the carbon nitride substrate has two reaction centers to form stable interfacial interaction with the NPs, in which carbon can act as the electron acceptor while nitrogen acts as the electron donor. Thus the NP-NCN system has a hybridized electronic structure which is favorable for the catalytic reaction to produce hydrogen. In-depth understanding of the interfacial interaction between NCN and NPs may also shed light on the mechanism study of various energy-related applications based on carbon nitride.