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Since the signing of the Minamata Convention in 2013, attempts have been primarily focused on reducing the emission of elemental mercury (Hg0) from coal-fired power plants (CFPPs). The most cost-effective measure for controlling the emission of mercury involves oxidizing Hg0 to mercury oxides, which are then removed using wet flue gas desulfurization (WFGD). Thus, novel photocatalysts with the best properties of photocatalytic ability and thermal stability need to be developed urgently. In this study, titanium dioxide (TiO2)-based photocatalysts were synthesized through the modification of three metal oxides: CuO, CeO2, and Bi2O3. All the photocatalysts were further characterized using X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence, and ultraviolet-visible spectrometry. The photocatalytic oxidation efficiencies of Hg0 were evaluated under an atmosphere of N2 + Hg0 at 100–200 °C. The photocatalytic reactions were simulated by kinetic modeling using the Langmuir–Hinshelwood (L–H) mechanism. The results showed that Bi2O3/TiO2 exhibited the best thermal stability, with the best oxidation efficiency at 200 °C and almost the same performance at 100 °C. L–H kinetic modeling indicated that photocatalytic oxidation reactions for the tested photocatalysts were predominantly physical adsorption. Additionally, the activation energy (Ea), taking into account Arrhenius Law, decreased dramatically after modification with metal oxides. [ABSTRACT FROM AUTHOR]

This article reviews the fundamental theories and reaction mechanisms of photocatalytic technologies with the assistance of electrical field for degrading multi-phase pollutants. Photo(electro)catalysis including photocatalytic oxidation (PCO) and photoelectrocatalytic oxidation (PECO) have been a potential technologies applied for the treatment of organic and inorganic compounds in the wastewaters and waste gases, which has been treated as a promising technique by using semiconductors as photo(electro)catalysts to convert light or electrical energy to chemical energy. Combining photocatalytic processes with electrical field is an option to effectively decompose organic and inorganic pollutants. Although photocatalytic oxidation techniques have been used to decompose multi-phase pollutants, developing efficient advanced oxidation technologies (AOTs) by combining photocatalysis with electrical potential is urgently demanded in the future. This article reviews the most recent progress and the advances in the field of photocatalytic technologies combined with external electrical field, including the characterization of nano-sized photo(electro)catalysts, the degradation of multi-phase pollutants, and the development of electrical assisted photocatalytic technologies for the potential application on the treatment of organic and inorganic compounds in the wastewaters and waste gases. Innovative oxidation techniques regarding photo(electro)catalytic reactions with and without oxidants are included in this review article. [ABSTRACT FROM AUTHOR]