Synthesis and optimization of catalytic materials for combustion of hydrocarbons in exhaust gases
Natural gas, an abundant energy resource with worldwide proven reserves of over 204.7 trillion m3, is used primarily for power generation and heating. The composition of natural gas (NG) is highly variable, but CH4 typically accounts for 80–90% of the components of NG. CH4 has the highest H/C ratio among all hydrocarbon fuels and during combustion, generates the lowest amount of CO2 per unit of energy. Exhaust gas emissions from NGVs are difficult to control because low concentrations of CH4 (400–1500 ppmv) must be oxidized in the presence of high concentrations of H2O (10-15 vol.%) and CO2 (15 vol.%) at relatively low exhaust gas temperatures (450–550 °C). The greater strength of the C-H bond in CH4 (~450 kJ/mol) relative to other hydrocarbon implies that catalysts with high CH4 oxidation activity must be used. Over the past ~20 years, conventional converter technologies have been adapted for NGVs using Pd catalysts (which have the highest activity for CH4 oxidation to adequately reduce (by 50–60%) the CH4 content in NGV exhausts at <500 °C in the presence of high H2O concentrations.We have explored several Pd based catalytic systems supported on ZrO2, SiO2, and Yttria stabilized ZrO2 for Methane and Ethylene oxidation. Catalysts are characterized by various techniques including XRD, N2-BET, O2-TPD, CO chemisorption, XRF and TEM. It is noted that modification of metal oxide support like ZrO2 with ailovalent Y2O3 in current work has played a significant role in catalyst stability and higher total oxidation at lower temperature. It is stated that further detailed investigations and optimization of dopant materials can help design catalysts of commercial viability.
Hassnain A. Khan obtained his MS, PhD degree in Clean Energy and Chemical Engineering from Korea Institute of Science and Technology South Korea, in 2019. His PhD work highlighted the Design of Catalytic systems for the water-splitting cycle to produce hydrogen and catalytic dehydrogenation of alkane into alkene, which are the basic building blocks for petrochemicals. He joined CCRC in February 2019 as a Post-doctoral fellow, in the group of Prof. Aamir Farooq. Hassanin’s current interests include experimental studies on exhaust after-treatment systems. Mostly he will be focusing on catalytic Methane and ethylene oxidation over supported catalysts.