A High-Performance Mn/TiO Catalyst with a High Solid Content for Selective Catalytic Reduction of NO at Low-Temperatures.

Mn/TiO catalysts with varying solid contents were innovatively prepared by the sol-gel method and were used for selective catalytic reduction of NO at low temperatures using NH (NH-SCR) as the reducing agent. Surprisingly, it was found that as the solid content of the sol increased, the catalytic activity of the developed Mn/TiO catalyst gradually increased, showing excellent catalytic performance. Notably, the Mn/TiO (50%) catalyst demonstrates outstanding denitration performance, achieving a 96% NO conversion rate at 100 °C under a volume hourly space velocity (VHSV) of 24,000 h, while maintaining high N selectivity and stability. It was discovered that as the solid content increased, the catalyst's specific surface area (SSA), surface Mn concentration, chemisorbed oxygen, chemisorption of NH, and catalytic reducibility all improved, thereby enhancing the catalytic efficiency of NH-SCR in degrading NO. Moreover, NH at the Lewis acidic sites and NH at the Bronsted acidic sites of the catalyst were capable of reacting with NO. Conversely, NO and NO adsorbed on the catalyst, along with bidentate and monodentate nitrates, were unable to react with NH at low temperatures. Consequently, the developed catalyst's low-temperature catalytic reaction mechanism aligns with the E-R mechanism.