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

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 mg_Co^-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.