Heock-Hoi Kwon

Effect of CO2 addition as an oxidant on the catalytic activity of K/MgO for acrylonitrile synthesis

The catalytic behavior of magnesium oxide doped with potassium oxide was investigated for acrylonitrile formation from acetonitrile and methanol. CO2 was applied as a mild oxidant. Under this oxidative condition, the reaction proceeded via an oxidative dehydrogenation pathway resulting in the increase of both acetonitrile conversion and acrylonitrile selectivity compared with the reaction under a non‐oxidative condition.

Nano-structured Carbon Support for Pt/C Anode Catalyst in Direct Methanol Fuel Cell

Platinum catalysts for the DMFC (Direct Methanol Fuel Cell) were impregnated on several carbon supports and their catalytic activities were evaluated with cyclic voltammograms of methanol electro-oxidation. To increase the activities of the Pt/C catalyst, carbon supports with high electric conductivity such as mesoporous carbon, carbon nanofiber, and carbon nanotube were employed. The Pt/e-CNF (etched carbon nanofiber) catalyst showed higher maximum current density of and lower on-set voltage of 0.54 V vs. NHE than the Pt/Vulcan XC-72 in methanol oxidation. Although the carbon named by CNT (carbon nanotube) series turned out to have larger BET surface area than the carbon named by CNF (carbon nanofiber) series, the Pt catalysts supported on the CNT series were less active than those on the CNF series due to their lower electric conductivity and lower availability of pores for Pt loading. Considering that the BET surface area and electric conductivity of the e-CNF were similar to those of the Vulcan XC-72, smaller Pt particle size of the Pt/e-CNF catalyst and stronger metal-support interaction were believed to be the main reason for its higher catalytic activity.

Single step synthesis of propionitrile over K/MgO from acetonitrile methylation with methanol

A series of potassium-doped MgO catalysts loaded with KOH up to 15 mol% was prepared and evaluated for a single step synthesis of propionitrile from acetonitrile methylation with methanol. As the amount of potassium dope increased, both the acetonitrile conversion and the selectivity toward propionitrile increased. Based on the activity data coupled with CO2-TPD and NH3-IR ones, it was concluded that potassium doping to MgO resulted in the enhancement of both basicity and bifunctionality — methylation and hydrogenation.