Enhanced photocatalytic Hg0 oxidation activity of iodine doped bismuth molybdate (Bi2MoO6) under visible light

Abstract

The application of photocatalytic Hg0 oxidation under visible light is an up-and-coming method to solve the problem of energy shortage and environmental pollution. In this work, iodine doped Bi2MoO6 nanomaterials were prepared by one-step solvothermal method. The photocatalytic oxidation efficiency was greatly improved by iodine doping from 35.5% to 95.2% in the N2 + 4% O2 atmosphere under visible light. The main reason was that iodine doping decreased the band gap of the catalyst, expanded the optical response range and intensity, sped up the separation rate of photoinduced carriers and reduced the recombination rate. In addition, the flue gas components of SO2 and NO played a promoting role in mercury removal. Iodine doped Bi2MoO6 had good stability and still maintained high mercury removal efficiency after 5 cycles. Density functional theory (DFT) calculations and experiments demonstrated that iodine doping changed the valence band and conduction band of the catalyst, making superoxide ions, hydroxyl radicals and photoinduced hole become the active species of the catalytic reaction.