Photocatalytic Synthesis of Ammonia over Fe2O3/ZnO with Rich Surface Oxygen Vacancy

Photocatalytic synthesis of ammonia is a sustainable and energy-saving synthetic ammonia technology. Rich oxygen vacancies and heterostructures are important to increase the photocatalytic nitrogen to ammonia. We synthesized Fe2O3/ZnO nanocomposites by solvothemtal method using ethylene glycol as the reducing agent. X-ray diffraction (XRD), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), UV-Vis DRS, photoluminescence (PL) and photocurrent (PC) were used to characterize the Fe2O3/ZnO catalysts. The performance of photocatalytic synthesis of ammonia by Fe2O3/ZnO catalysts Was tested at room temperature. The results show that heterostructure was formed between ZnO nanorods and Fe2O3, nanoparticles while abundant surface oxygen vacancies were produced over the Fe2O3/ZnO catalysis. Fe2O3 nanoparlieles not only provide rich N-2 chemical adsorption sites, but also promote the light absorption of ZnO in the visible region. The :introduction of Fe2O3 reduces the concentration of bulk oxygen vacancies and :inhibits the recombination of photogenerated electrons and holes. The 4%Fe2O3/ZnO catalyst exhibited enhanced photocatalytic nitrogen "fixation efficiency with a NH3 rate of 2 059 mu mol.L-1.g(-1).h(-1) Ivith better stability. The high catalytic efficiency is attributed to the enhancement of visible light absorption, the activation of nitrogen molecules on surface oxygen vacancies and Fe3+ active sites, and the high separation efficiency of photogenerated electrons and holes.