Unveiling a remarkable enhancement role by designing a confined structure Ho-TNTs@Mn catalyst for low-temperature NH-SCR reaction.

MnO-based catalysts are considered promising alternative catalysts for NH-SCR to remove NO at low temperature. However, their poor SO or HO tolerance and unfavorable N selectivity are still the main obstacles restraining their further practical application. Herein, we carefully confined the manganese oxide active species in Ho-modified titanium nanotubes to improve their SO resistance and N selectivity.

Engineering 3D structure Mn/YTiO nanotube catalyst with an efficient HO and SO tolerance for low-temperature selective catalytic reduction of NO with NH.

TiO with a 3D structure is considered to be a promising support for Mn-based catalysts for the NH-SCR reaction, but it is still insufficient to solve problems such as poor N selectivity and tolerance of HO/SO at low temperature. In this work, a novel 3D-structured Mn/YTiO nanotube catalyst was designed and the role of Y on the catalytic performance was investigated for the NH-SCR reaction at low temperature. The results indicated that the Y-doped TiO gradually transformed from nanotubes to nanosheets with the increase in Y doping, leading to a reduction in specific surface area and Brønsted acid sites.

The roles of Brønsted acidity in low-temperature catalytic oxidation of NO over acidic zeolites with HO.

In this study, low-temperature catalytic NO oxidation with HO over Na- and H-exchanged Y and ZSM-5 zeolites was investigated at 140 °C which is the average exhaust temperature of coal-fired power plant. Fast catalytic NO oxidation rates were observed over H-zeolites, and catalytic activity was proportional to the amount of Brønsted acid sites. HZSM-5 and HY zeolites show 65% and 95% NO removal efficiency, respectively, but the catalytic stability of HY was lower than HZM-5 due to partial dealumination during the reaction.

Simultaneous removal of NOx and SO with HO over silica sulfuric acid catalyst synthesized from fly ash.

Considering that the utilization of fly ash in the removal of flue gas pollutants not only provide a way of high value-added utilization of fly ash, but also greatly reduce the cost of removing flue gas pollutant, the synthesis of silica sulfuric acid catalyst from fly ash and its application in simultaneous removal of NOx and SO with HO were investigated in this work. Circulating fluidized bed boiler (CFB) fly ash and pulverized coal boiler (PC) fly ash were selected as raw material to prepare silica sulfuric acid catalyst by HSO activation. PC fly ash was difficult to be activated by HSO due to its dense structure, while CFB fly ash could be treated with HSO to promote dealumination, thereby increasing the silica content.

NO oxidation over Fe-based catalysts supported on montmorillonite K10, γ-alumina and ZSM-5 with gas-phase HO.

The catalytic gas-phase HO oxidation of NO was achieved over Fe-based catalysts supported on montmorillonite K10, γ-alumina and ZSM-5. ESR tests illustrate that the three catalysts can catalyze decomposition of HO yielding highly reactive hydroxyl radicals, of which Fe/K10 has the fastest rate, followed by Fe/γ-alumina. Fe in Fe/K10 and Fe/γ-alumina show lower density of electron cloud due to a strong interaction between Fe and the support, which benefits the electron transfer from the HO to Fe, thus favoring the production of hydroxyl radicals.