Self-Assembly of Hierarchical Ni-Mo-Polydopamine Microflowers and their Conversion to a Ni-Mo2C/C Composite for Water Splitting

With the aim of finding efficient non-noble metal catalysts for water splitting, hierarchical Ni-Mo-polydopamine microflowers (Ni-Mo2C/C MF) were synthesized through a facile aqueous-phase reaction at room temperature. NiMoO4 nanowires were utilized as both Ni and Mo source; they can complex with dopamine to form a hierarchical structure and affect the scale of the final product. The energy dispersive spectroscopy (EDS) measurement of Ni-Mo2C/C microflowers (MF) shows a high content of Mo2C and Ni (>90wt%). For the hydrogen evolution reaction (HER), the Ni-Mo2C/C MF displays a low overpotential of 99mV at a current density of -10mAcm(-2) and a small Tafel slope of 73mVdec(-1) in 1.0m KOH. By comparison with Mo2C/C microspheres (MS), the nanosized Ni-doped particles offer more active sites and enhance the kinetic performance. This facile synthesis strategy is also suitable for preparing other metal-Mo2C/C composites that can be used in the fields of catalysis and energy conversion.