Integration of Fe2O3-based photoanode and atomically dispersed cobalt cathode for efficient photoelectrochemical NH3 synthesis

Abstract Realizing nitrogen reduction reaction (NRR) to synthesis NH3 under mild conditions has gained extensive attention as a promising alternative way to the energy- and emission-intensive Haber–Bosch process. Among varieties of potential strategies, photoelectrochemical (PEC) NRR exhibits many advantages including utilization of solar energy, water (H2O) as the hydrogen source and ambient operation conditions. Herein, we have designed a solar-driven PEC-NRR system integrating high-efficiency Fe2O3-based photoanode and atomically dispersed cobalt (Co) cathode for ambient NH3 synthesis. Using such solar-driven PEC-NRR system, high-efficiency Fe2O3-based photoanode is responsible for H2O/OH- oxidation, and meanwhile the generated photoelectrons transfer to the single-atom Co cathode for the N2 reduction to NH3. As a result, this system can afford an NH3 yield rate of 1021.5 μg mgCo-1 h-1 and a faradic efficiency of 11.9% at an applied potential bias of 1.2 V (versus reversible hydrogen electrode) on photoanode in 0.2 mol/L NaOH electrolyte under simulated sunlight irradiation.