Fluorinated Ni-O-C Heterogeneous Catalyst for Efficient Urea-Assisted Hydrogen Production

Constructing multiple heterogeneous structures allows for improving the electrocatalytic activity of NiO by incorporating multiple active sites. Unfortunately, the poor conductivity of NiO makes efficient charge transfer within the heterogeneous structures difficult, thereby inhibiting the improvement of its intrinsic activity. Herein, F-doped NiO/Ni@C heterogeneous catalyst (F-NiO/Ni@C) is fabricated via a new organic-inorganic hybrid approach, showing both advanced hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) activity. The targeted F-doping increases electron delocalization, and facilitates electron transfer from Ni to NiO at the nano-interfaces. This interphase synergy provides ready-to-use F-NiO active sites, allowing F-NiO/Ni@C to achieve optimum H* adsorption Gibbs free energy for HER and a lower energy barrier for UOR. As a result, the as-configured F-NiO/Ni@C || F-NiO/Ni@C cell requires an ultra-low cell voltage of 1.37 V to achieve 10 mA cm −2 in alkaline media (with 0.3 M urea), outperforming the state-of-the-art benchmark Pt/C|| RuO 2 cell (1.45 V). This study reveals the positive impact of anion doping on interphase synergy and provides useful guidelines for designing monometallic catalysts for UOR as well as hydrogen generation.