Inhak Song

Abstract NO x abatement has been an indispensable part of environmental catalysis for decades. Selective catalytic reduction with ammonia using V 2 O 5 /TiO 2 is an important technology for removing NO x emitted from industrial facilities. However, it has been a huge challenge for the catalyst to operate at low temperatures, because ammonium bisulfate (ABS) forms and causes deactivation by blocking the pores of the catalyst. Here, we report that physically mixed H-Y zeolite effectively protects

Controlling selectivity in heterogeneous catalysis is essential for designing processes that minimize the production of undesired byproducts. For example, TiO2-supported manganese oxide, a promising material for catalyzing the selective reduction of NO with NH3 at very low temperatures, is currently restricted by poor selectivity because of the production of unwanted N2O, which has a greenhouse gas potential 300 times higher than that of CO2. In this study, we located manganese oxides in micropo

Keggin-type heteropolyacids (water-soluble H 3 PMo 12 O 40, H 4 PMo 11 VO 40, and H 8 PMo 10 VCuO 40 and water-insoluble K 3 PMo 12 O 40 and H 3 - x Cs x PMo 12 O 40, x = 1, 2, 2.5, 3) deposited on highly oriented pyrolytic graphite (HOPG) surfaces were successfully imaged by scanning tunneling microscopy (STM). All of these heteropoly acids (HPAs) formed clear two-dimensional ordered arrays on graphite, and their periodicities were in good agreement with values determined by X-ray crystallograp

V/TiO2 catalysts are used in various reactions, including oxidative dehydrogenation, partial oxidation of ethanol, and selective catalytic reduction of NOx with NH3. In this work, we investigated the effect of supported monomeric vanadium oxide (VO3) on the acidity of anatase TiO2(101) surface by using density functional theory calculations combined with in situ diffuse reflectance infrared Fourier transform (DRIFT) experiments. The hydrogenation of TiO2 to form hydroxyl groups on the surface wa

Ultrasmall Pd 4 clusters form in the micropores of FER zeolite during low-temperature treatment (100 °C) in the presence of humid CO gas. They effectively catalyze CO oxidation below 100 °C, whereas Pd nanoparticles are not active as they are poisoned by CO. Using catalytic measurements, infrared (IR) spectroscopy, X-ray absorption spectroscopy (EXAFS), microscopy, and density functional theory calculations, we provide the molecular-level insight into this previously unreported phenomenon. Pd na

Pd-ion-exchanged zeolites have emerged as promising materials for the adsorption and oxidation of air pollutants. For low-temperature vehicle exhaust, dispersed Pd ions can adsorb NOx even in H2O-rich exhaust containing carbon monoxide. To understand this phenomenon, changes in the Pd ligand environment have to be monitored in situ. Herein, we directly observe the activation of hydrated Pd ion shielded by H2O into a carbonyl–nitrosyl complex Pd2+(NO)(CO) in SSZ-13 zeolite. The subsequent thermal

-SCR) is under debate. Here, a Li doping strategy is applied to selectively block Brønsted sites, which aims to prepare model catalysts with the same V loading but different ratios of the two acid sites. Time-resolved in situ DRIFTS observation demonstrates that the surface ammonia species pre-adsorbed on Lewis and Brønsted sites can participate equally in the reaction. Consideration of site redistribution in the early stages of the transient reaction is key to accurate measurement of the ammoni