High-spin state Fe(III) doped TiO2 for electrocatalytic nitrogen fixation induced by surface F modification

It is a challenging task to overcomes the bottleneck of N2 adsorption and activation in N2 reduction reaction (NRR). Regulating the catalyst surface electronic state is treated as a potential strategy to prevail over the barrier. Here, Incorporating Fe as a dopant in the TiO2 nanoparticles can generate oxygen vacancies and dopant energy levels, promoting the adsorption and activation of N2 molecules. F surface modification induces Fe (III) in the high spin state and upshifts the dopant energy level. That facilitates Fe 3d electrons backdonation to N 1ag* orbital promotes the activation of N2 molecule and reduces the limiting potential of NRR. Therefore, F-Fe: TiO2 electrocatalyst achieved the highest Faradaic efficiency and maximum NH3 production rate of 27.67% and 27.86 mu g h-1 mgcat. -1 at -0.5 V v.s. reversible hydrogen electrode. This work provides deep insights into the design surface electronic state of catalyst toward efficient N2 to NH3 conversion.