Herein, PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness are synthesized via a polyvinyl alcohol (PVA) involved approach and used for hydrogen evolution reaction (HER). The average crystallite size of the PVA protected nMo 2 CN nanospheres (6.1 nm) is one third of that of the PVA-Mo 2 C/Mo 2 N without PVA protection (17.9 nm). At 10 mA cm −2 current density, the as-synthesized PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness exhibit HER overpotentials of 132 mV and 142 mV with corresponding Tafel slope of 51.8 mV dec −1 and 50.4 mV dec −1 in acid and alkaline medium, respectively. This high apparent activity can be attributed to the high intrinsic activity originated from the adjacent surface active sites of Mo 2 C and Mo 2 N as well as the large ECSA of PVA-Mo 2 C/Mo 2 N nanospheres with surface roughness.
Growing demand for clean and renewable energy resources has sparked intensive research on the development of an effective strategy to prepare non-noble metal electrocatalysts for oxygen evolution reaction (OER). Herein, we report a new type of N-doped carbon coated CoP particle/carbon nanotube composite (CNT-NC-CoP) has been synthesized by in situ nucleation and growth of ZIF-67 nanoparticles onto carbon nanotubes, which subsequently is treated with carbonization and phosphorization. Unique hierarchical structure endows as-obtained CNT-NC-CoP with high specific surface area , abundant exposed active sites, quick ion diffusion path , and good electrical conductivity , thus exhibiting the highest electrocatalytic capability with the low overpotential of 251 mV at the current density of 10 mA cm −2 and remaining long-term durability (overlapping LSV curve after 10 h). Besides, density functional theory (DFT) calculations reveal that CoOOH/graphene charged surfaces are more effective for facilitating intermediates adsorption and improving the corresponding catalytic activity .
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