Urchin-like Ni-Co-P-O nanocomposite as novel methanol electro-oxidation materials in alkaline environment

A facile one-pot solvothermal method is proposed to fabricate a new series of Ni-Co-P-O compound-based electrocatalysts for methanol oxidation in alkaline environment. It is found that the chemical composition, surface morphology, as well as the crystallographic structure of the final Ni-Co-P-O composites are largely depends on the Co2+/Ni2+ molar ratios in the reaction system. The sample of NiCoPO-2 possessing an urchin-like architecture and a hybrid composition of nano-scaled Ni/Co phosphides and phosphates was produced at a Co2+/Ni2+ molar ratio of 0.18. A larger specific surface area of 540.5 m2 g−1 and a bimodal pore size distribution are found in the NiCoPO-2 sample. As a potential catalyst, the NiCoPO-2 delivers a highest oxidation current density (∼1567 A g−1) and a good durability (≥20000 s) toward the methanol electrooxidation reaction. The superior catalytic performance of the NiCoPO-2 catalyst should be attributed to its unique microstructure and compositions. It is also supposed that the formation of electron tunneling junctions between the metal phosphides and phosphates could provide new channels for facilitating electron transfer throughout the composite electrocatalysts.