Synthesis of Vanadium-Containing Catalytically Active Phases for Exhaust Gas Neutralizers of Motor Vehicles and Industrial Enterprises

The catalytically active vanadium-containing system of γ-Al2O3 was studied using a wide range of physical and chemical methods, depending on the synthesis conditions. It is shown that the vanadium-containing system includes several complexes with different thermal stabilities and catalytic activities. Low-active complexes are destroyed with the formation of more active ones based on V2O5 oxide, as the temperature of heat treatment increases. It can be assumed that V2O5 oxide has the decisive role in its catalytic activity. It was concluded that the vanadium-containing catalytic system on aluminium oxide, in the studied temperature range, is thermally stable and shows high activity not only in the reduction of nitrogen oxides but also in the oxidation of hydrocarbons (even of the most difficult ones, such as oxidizable methane). These properties of the system make it quite promising in the field of application for the purification of the exhaust gases of motor transport and industrial enterprises with environmentally harmful components, as well as for understanding the mechanism of the action of the catalysts in these processes, which is very important for solving the problems of decarbonization and achieving carbon neutrality.

Determination of the Conditions for Carbon Materials Oxidation with Carbon Monoxide Formation at High Temperatures

In this paper, the influence of carbon material type, temperature and oxygen concentration in gas mixture on the processes of carbon monoxide formation in production of the electrodes by graphitization was explored experimentally. Specific quantity of gas formed for a definite time, reduced to mass unit of carbon loading using pitch, packing materials and charge mixture of industrial use, was calculated. It is demonstrated that pitch provides the highest rate of carbon oxidation with the release of CO and substantially exceeds packing materials and charge mixture for this index.

Current scenario of CNG vehicular pollution and their possible abatement technologies: an overview

Compressed natural gas is an alternative green fuel for automobile industry. Recently, the Indian government is targeting to replace all the conventional fuel vehicles by compressed natural gas (CNG) automobiles due to its several merits. Still, the presence of a significant amount of CO, CH₄, and NO_x gases in the CNG vehicle exhaust are quiet a matter of concern. Thus, to control the emissions from CNG engines, the major advances are under development of and oxidation is one of them in catalytic converter. In literature, the catalysts such as noble and non-noble metals have been reported for separate oxidation of CO and CH_4.. Experimentally, it was found that non-noble metal catalysts are preferred due to its low cost, good thermal stability, and molding tractability. In literature, several articles have been published for CO and CH₄ oxidation but no review paper is still available. Thus, the present review provides a comprehensive overview of separate as well as simultaneous CO and CH₄ oxidation reactions for CNG vehicular emission control.

Catalytic Technologies for Solving Environmental Problems in the Production of Fuels and Motor Transport in Kazakhstan

This research is devoted to solving an environmental problem, cleaning of the Kazakhstan air basin, through treatment of auto-transport toxic exhaust by improving the hydrocarbon composition of motor fuels and neutralizing exhaust gas toxic components. The catalytic hydrodearomatization of gasoline fractions (from the reforming stage) of the Atyrau and Pavlodar Refineries and the neutralization of exhaust gas toxic components from an internal combustion engine (ICE) were studied. Two hydrotreated gasoline fractions were tested during ICE operation. The research shows that 100% benzene conversion is observed over Rh-Pt(9:1)/γ-Al2O3 catalysts; that is, benzene is completely removed from both fractions, and the aromatics content decreases from 56.24–58.12% to 21.29–21.89%, within the values of the Euro-5,6 standard. Catalytic treatment of fuels reduces fuel consumption of the ICE engine by 2–3% compared to the initial gasoline fractions, the CO content in the exhaust gases decreases by 6.6–16.2%, and the hydrocarbon content decreases by 7.8–24.7%. In order to neutralize the ICE exhaust gas toxic components, the catalyst 10% Co + 0.5% Pt/Al2O3 was used, with which the CO conversion reaches 100% and the hydrocarbon conversion 94.2% and 91.5% for both gasoline fractions. The catalysts were characterized by electron microscopy (EM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), thermoprogrammed desorption (TPD) and thermoprogrammed reduction (TPR) methods. It was shown by the TPD and EM methods that at the addition of Pt to the Rh-catalyst, the formation of mixed bimetallic Rh-Pt-agglomerates occurs, and hydrogen appears in the TPD spectrum, adsorbed in the form of a new single peak uncharacteristic for the Rh-catalyst. This leads to high activity and selectivity in the hydrogenation of benzene and aromatic compounds in the gasoline fractions. The XRD and TPR results show the formation of CoAl2O4 spinels, on which inactive oxygen is formed for the oxidation of CO and hydrocarbons. Modification of the catalyst by Pt and Mg prevents spinel formation, thereby increasing the activity of the catalysts.