The simultaneous removal of nitrogen oxides (NO_x) and sulfur dioxide (SO₂) by absorption is considered to be one of the most promising technologies for flue gas treatment, and sulfite is the main component of the absorption solution. To understand the chemical behaviors of the NO₂ absorption in sulfite solution, the absorption time dependences of concentrations of nitrogen and sulfur compositions in both gas phase and liquid phases were investigated by flue gas analyzer, Ion chromatography (IC), Gas chromatography (GC), and Fourier transform infrared spectrometry (FTIR) methods using a bubbling reactor. The mass equilibrium of the N and S compositions were also studied. The results indicate that sulfite concentration plays a vital role in NO₂ absorption. The main absorption products are NO₃⁻ and NO₂⁻, and NO₂⁻ can be converted into NO₃⁻ in the presence of oxygen. Besides, about 4% to 9% by-products of S compositions are formed, and 4% to 11% by-products of N compositions such as NO, N₂, N₂O₅, N₂O, and HNO₃ in the gas phase were detected in the emissions from the bubbling reactor. On the basis of N and S compositions, a possible pathway of NO₂ absorption in sulfite solution was proposed.

A series of MnO_x–CeO₂ and MnO_x–TiO₂ catalysts were prepared by a homogeneous precipitation method and their catalytic activities for the NO oxidation in the absence or presence of SO₂ were evaluated. Results show that the optimal molar ratio of Mn/Ce and Mn/Ti are 0.7 and 0.5, respectively. The MnO_x–CeO₂ catalyst exhibits higher catalytic activity and better resistance to SO₂ poisoning than the MnO_x–TiO₂ catalyst. On the basis of Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and scanning transmission electron microscope with mapping (STEM-mapping) analyses, it is seen that the MnO_x–CeO₂ catalyst possesses higher BET surface area and better dispersion of MnO_x over the catalyst than MnO_x–TiO₂ catalyst. X-ray photoelectron spectroscopy (XPS) measurements reveal that MnO_x–CeO₂ catalyst provides the abundance of Mn³⁺ and more surface adsorbed oxygen, and SO₂ might be preferentially adsorbed to the surface of CeO₂ to form sulfate species, which provides a protection of MnO_x active sites from being poisoned. In contrast, MnO_x active sites over the MnO_x–TiO₂ catalyst are easily and quickly sulfated, leading to rapid deactivation of the catalyst for NO oxidation. Furthermore, temperature programmed desorption with NO and O₂ (NO + O₂-TPD) and in situ diffuse reflectance infrared transform spectroscopy (in situ DRIFTS) characterizations results show that the MnO_x–CeO₂ catalyst displays much stronger ability to adsorb NO_x than the MnO_x–TiO₂ catalyst, especially after SO₂ poisoning.

In this work, a simple hydrothermal method was used to prepare a series of ZnO/r-GO (ZGO-x) catalysts. The obtained products were subjected to a series of characterizations, which showed that the zinc oxide particles were deposited onto r-GO and that the crystal structure was not disrupted. In addition, due to the large specific surface area and the good electrical conductivity of r-GO, more photogenerated electrons can be rapidly transferred from ZnO to r-GO to participate in the reaction, thus improving the photocatalytic performance. The degradation rate of the ZGO-3 sample reached 100% for RhB after simulated sunlight irradiation for 150 min, whereas the pure ZnO degraded RhB by about 83% under the same environment. ZGO-3 also showed the best photocatalytic degradation of methyl orange, with 100% degradation in 180 min, whereas pure ZnO degraded only 87.64% of methyl orange under solar irradiation.

High-concentration CaO particles and gas compositions have a significant influence on NO_x reduction by selective non-catalytic reduction (SNCR) in cement precalciners. The effect of gas composition on NO_x reduction by SNCR with NH₃ was studied in a cement precalciner atmosphere with and without CaO at 700–1100 °C. It was found that CaO significantly lowers NO_x reduction efficiency between 750 °C and 1000 °C, which is attributed to the catalytic oxidation of NH₃ to NO. Although increasing NH₃ concentration was advantageous to NO_x reduction, the existence of CaO led to the opposite result at 750–900 °C. Adding H₂O can suppress the negative effect of CaO on NO_x reduction. Decreasing O₂ content from 10% to 1% shifts the temperature range in which CaO has a significant effect from 750–1000 °C to 800–1050 °C. CO has a variety of influences on the CaO effect under different experimental conditions. The influences of NH₃, H₂O, O₂, and CO on the effect of CaO can be attributed to the impacts of the gas compositions on gas-phase NH₃ conversion, gas-solid catalytic NH₃ oxidation, or both processes. A proposed pathway for the effect of gas compositions on NO_x reduction in CaO-containing SNCR process was developed that well predicted the CaO-containing SNCR process.

A series of nanostructured Pt-Au/MO_x-CeO₂ (M = Mn, Fe, Ti) catalysts were prepared and their catalytic performance for the co-oxidation of carbon monoxide (CO) and hydrogen (H₂) were evaluated at room temperature. The results showed that MO_x promoted the CO oxidation of Pt-Au/CeO₂, but only the TiO₂ could enhance co-oxidation of CO and H₂ over Pt-Au/CeO₂. Related characterizations were conducted to clarify the promoting effect of MO_x. Temperature-programmed reduction of hydrogen (H₂-TPR) and X-ray photoelectron spectroscopy (XPS) results suggested that MO_x could improve the charge transfer from Au sites to CeO₂, resulting in a high concentration of Ce³⁺ and cationic Au species which benefits for the CO oxidation. In-situ diffuse reflectance infrared Fourier transform spectroscopy (In-situ DRIFTS) results indicated that TiO₂ could facilitate the oxidation of H₂ over the Pt-Au/TiO₂-CeO₂ catalyst.

An efficient multi-component reaction to synthesize multi-substituted 1,3-oxazolidine compounds of high optical purity was described. All the products were well-characterized and the absolute configuration of one chiral center was determined. The plausible mechanism was proposed and a kinetic resolution of epoxides process was confirmed.