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Catalytic ozonation is a new method used for removal of NH4OH solution. Therefore, high catalytic performance (activity and selectivity) should be achieved. In this work, we report the synthesis and catalytic performance of Fe2O3-Co3O4 modified dolomite in the catalytic ozonation of NH4OH solution. Dolomite was successfully activated and modified with Fe2O3 and Co3O4. Firstly, dolomite was activated by heating at 800°C for 3 h and followed by KOH treatment. Activated dolomite was modified with Fe2O3 by the atomic implantation method using FeCl3 as Fe source. Fe2O3 modified dolomite was further modified with Co3O4 by precipitation method. The obtained catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), N2 adsorption–desorption (BET), and temperature-programmed reduction (H2-TPR). From SEM image, it was revealed that nano-Fe2O3 and Co3O4 particles with the size of 80–120 nm. Catalytic performance of activated dolomite, Fe2O3 modified dolomite, and Fe2O3-Co3O4 modified dolomite in catalytic ozonation of NH4+ solution was investigated and evaluated. Among 3 tested catalysts, Fe2O3-Co3O4 modified dolomite has the highest NH4+ conversion (96%) and N2 selectivity (77.82%). Selectivity toward N2 over the catalyst was explained on the basis of bond strength M-O in oxides through the standard enthalpy Δ H ° f of oxide. Catalyst with lower Δ H ° f value has higher N2 selectivity and the order is the following: Co3O4 (Δ H ° f of 60 kcal (mole O)) > Fe2O3 (Δ H ° f of 70 kcal (mole O)) > MgO (Δ H ° f of 170 kcal (mole O)). Moreover, high reduction ability of Fe2O3-Co3O4 modified dolomite could improve the N2 selectivity by the reduction of NO3- to N2 gas. [ABSTRACT FROM AUTHOR]

Summary Catalytic stability with time‐on‐stream is an important aspect in ethanol dry reforming (EDR) since catalysts could encounter undesirable deterioration arising from deposited carbon. This work examined the promotional effect of La on 10%Co/Al2O3 in terms of activity, stability, and characteristics. Catalysts were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman, and X‐ray photoelectron spectroscopy (XPS) measurements whilst catalytic EDR performance of La‐promoted and unpromoted 10%Co/Al2O3 prepared via wet impregnation technique was investigated at 973 K for 72 h using a stoichiometric feed ratio (C2H5OH/CO2 = 1/1). La promoter substantially enhanced both metal dispersion and metal surface area from 0.11% to 0.64% and 0.08 to 0.43 m2 g−1, respectively. Ethanol and CO2 conversions appeared to be stable within 50 to 72 h after experiencing an initial activity drop. The conversion of C2H5OH and CO2 for La‐promoted catalyst was about 1.65 and 1.34 times greater than unpromoted counterpart in this order. The carbonaceous deposition was considerably decreased from 55.6% to 36.8% with La promotion due to La2O2CO3 intermediate formation. Additionally, 3%La‐10%Co/Al2O3 possessed greater oxygen vacancies acting as active sites for CO2 adsorption and hence increasing carbon gasification. Even though graphitic and filamentous carbons were formed on used catalyst surface, La‐addition diminished graphite formation and increased the reactiveness of amorphous carbon. La‐promotion on Co/Al2O3 significantly improved metal dispersion, metal surface area, activity, and stability for ethanol dry reforming.La2O2CO3 intermediate formation with La promotion reduced carbon deposition about 33.8%.3%La‐10%Co/Al2O3 catalyst owned greater oxygen vacancies, thereby suppressing carbonaceous deposition. [ABSTRACT FROM AUTHOR]