Nowadays the air pollution caused by NO and CO needs to be solved urgently. Precious metal catalyst has good activity but is expensive. Transition metal oxide catalyst is low in cost, and support transition metal oxide can improve the catalytic activity. The metal oxides synthesized by traditional methods often have uneven loading due to their irregular morphology and small pore size. So we select MOFs with abundant pore structures and controllable morphologies as the carriers. This paper Cu-BTC (BTC is trimellitic acid radical) as the template was loaded with different proportions of Co by impregnation method, and then heterogeneous commensal metal oxide containing carbon skeleton with regular morphology, excellent performance and stability were prepared by calcination. Samples were characterized by SEM, EDX, TEM, TG, XRD, H2-TPR, XPS, BET and in situ DRIFTS. The pyrolysis of cobalt-loaded CuBTC resulted in the multi-phase coexisting metal oxide of CuO, Cu2O and Co3O4, with a highly dispersed carbon on the surface of the catalysts. The carbon containing lone electrons could promote the electron transfer between Cu and Co, thus improving the catalytic activity. The best catalytic ability was Co-0.75-CuOx/C, and reaction mechanism on it was E-R mechanism (& LE;200 celcius) and L-H mechanism (225-300 celcius).

NOx is one of the main sources of air pollution, and the abatement of NOx emission has aroused increasing attention. The NH3-SCR technology is mature and widely used for controlling NOx emissions from fixed sources. In this work, SmxMnTiSnOy was synthesized by a mixed solvothermal synthesis. The NH3-SCR performance of SmxMnTiSnOy was tested and the H2O and SO2 resistance of Sm0MnTiSnOy, Sm0.1MnTiSnOy, and Sm0.2MnTiSnOy catalysts (5 %H2O, 25 ppm SO2) were tested at 250 ?. The physicochemical properties of SmxMnTiSnOy were studied by XRD, FESEM, TEM, BET, XPS, H-2-TPR, NH3-TPD and In-situ DRIFTS. The experimental results reveal that Sm0.2MnTiSnOy has a better low-temperature NH3-SCR performance and splendid H2O and SO2 durability. Moreover, appropriate Sm doping increases the specific area and enhances the acidity of the catalyst's surface. The In-situ DRIFTS results suggest that the adsorption and activation of NH3 are of primary importance in the NH3-SCR reaction. Besides, a large number of weak acid sites on Sm0.2MnTiSnOy are conducive to adsorb and activate NH3 and good redox ability facilitates the activation of bidentate nitrate, respectively. Meanwhile, Sm doping could transfer electrons from the Sm species to the Mn species, which inhibits the formation of Mn sulfate.

The Zr-modified CeTiOx mixed oxide catalyst with good NH3-SCR activity and SO2 resistance was synthesized and reduced by H-2. Performance test revealed that the obtained R-CZT-20/1 (Ce: Zr: Ti = 20: 1: 100) catalyst exhibited outstanding low-temperature activity after H-2 reduction treatment, which achieved upon 98% NO conversion at 200-350 degrees C. Remarkably, it possessed excellent SO2 resistance as well as good reversibility, with the activity decreased from 100% to 96%. Meanwhile, R-CZT-20/1 possessed more surface acid sites and oxygen defects, which promoted the chemical adsorption and activation of NO and NH3 on the catalyst surface. XPS results confirmed that R-CZT-20/1 enriched Ce3+, accelerated the electron transfer between Ce3++ Ti4+ -> Ce4++ Ti3+, and generated a large number of oxygen vacancies. Moreover, there is strong synergistic effect between Ce-Zr-Ti, which might be the reason for the excellent SO2 resistance. Among them, the presence of Zr facilitated the favorable process. In situ DRIFTS experiments indicated that the unreduced catalysts followed E-R and L-H mechanism at low and high temperatures, respectively, while R-CZT-20/1 obeyed only the L-H mechanism.

As an ideal substitute for the precious metals in the selective catalytic reduction of NO by CO, transition metal oxides perform very well. Thus, a series of CuO - Co3O4 symbiotic oxide porous nanosheet catalysts are prepared with a CTAB-assisted hydrothermal method. Cu5 with the ratio of Cu and Co is 5 : 10, has the best activity on the premise of maintaining the nanosheet structure. Reduction pretreatment of Cu5 with H2 is carried out, and the surface will be rapidly oxidized in air. In this period, Cu, CuO and Co3O4 were produced and coexisted on surface. Cu5-re-163 exhibits greatly higher N2 selectivity but a little inferior NO conversion. Further DFT calculation and characterizations proved that [N] free radicals exist during the reaction. The reaction on Cu5 and Cu-re-163 follow L-H and E-R mechanism respectively. [N] radicals on the latter are much easier to desorb, so that they are easy to combine with each other to form N2 rather than with NO to generate N2O, as the reason why Cu5-re-163 has better selectivity.

The loading of Mn on TiO2 for NH3-SCR has good low temperature catalytic activity and has been extensively studied. In this experiment, a series of second metals (Ce, Fe, Co, Ni) were added to modify the Mn/TiO2 mixed oxide. The experimental results show that Ni-Mn/TiO2 has excellent catalytic activity, but the addition of Co element did not increase the catalytic activity. The excellent catalytic activity of Ni-Mn/TiO2 is mainly due to its the strong interaction, which enhances the reducibility, increases the total acid amount, Ti3+ ratio, Mn4+ ratio, and the proportion of adsorbed oxygen. These factors facilitate the adsorption and activation of reactant molecules. In addition, in situ DRIFTS results indicate that both the B acid site and the L acid site function at 200 degrees C, bidentate nitrate not participate in the catalytic reaction and the Langmuir-Hinshelwood (L-H) mechanism dominates at 200 degrees C.

Monometallic and bimetallic MOF-74-M (M = Mn, Co, Ni, Zn, MnCo, MnNi, and MnZn) catalysts were prepared by the solvothermal method for NH3-SCR. XRD, BET, SEM, and EDS-mapping tests indicate the successful synthesis of the MOF-74-M catalyst with uniform distribution of metal elements and large specific surface area, and the morphology is almost hexagonal. Adding Mn element to a single-metal catalyst can enhance activity, which is mainly because of the existence of various valence states of Mn so that it has excellent redox properties; the catalytic activity of water and sulfur resistance tests showed that the catalytic activity of MOF-74-M increases after adding a proper amount of SO2, mainly because of the increase in acidic sites. In situ DRIFTS results indicate that the low-temperature range of MOF-74-MnCo and MOF-74-Mn is dominated by the E-R mechanism and the high-temperature range is dominated by the L-H mechanism. The entire temperature range of MOF-74-Zn is dominated by the L-H mechanism.

A series of samples with the precursor's molar ratio of {KMn8O16}/{CuFe2O4} = 0, 0.008, 0.010, 0.016, and 0.020 were successfully synthesized for selective catalytic reduction of NO by CO. The physicochemical properties of all samples were studied in detail by combining the means of X-ray photoelectron spectroscopy, H2-temperature-programmed reduction, scanning electron microscopy mapping, X-ray diffraction (XRD), N2 physisorption (Brunauer-Emmett-Teller), NO + CO model reaction, and in situ Fourier transform infrared spectroscopy techniques. The results show that three phases of γ-Fe2O3, CuFe2O4, and CuO, which have strong synergistic interaction, coexist in this catalyst system, and different phases play a leading role in different temperature ranges. Mn species are highly dispersed in the three-phase coexisting system in the form of Mn2+, Mn3+, and Mn4+. Because of the strong interaction between Mn2+ and Fe species, a small amount of Cu2+ precipitates from CuFe2O4 and grows along the CuO(110) plane, which has better catalytic performance. Mn3+ can inhibit the conversion of γ-Fe2O3 to α-Fe2O3 at high temperature and then increases the high-temperature activity. The synergistic effect between Mn4+ and the surfaces of three phases generates active oxygen species Cu2+-O-Mn4+ and Mn4+-O-Fe3+, which can be more easily reduced to some synergistic oxygen vacancies during the reaction. Furthermore, the formed synergistic oxygen vacancies can promote the dissociation of NO and are also propitious to the transfer of oxygen species. All of these factors make the appropriate manganese-modified three-phase coexisting system have better catalytic activity than the manganese-free catalyst, making NO conversion rate reach 100% at around 250 °C and maintain to 1000 °C. Combining comprehensive analysis of various characterization results and in situ infrared as well as XRD results in the equilibrium state, a new possible NO + CO model reaction mechanism was temporarily proposed to further understand the catalytic processes.