New Ethanol-Assisted Catalyst Design Dramatically Improves Low-Temperature Nitrogen Oxide Removal

(Biochar Editorial Office, Shenyang Agricultural University/EurekAlert!) A research team has developed a new strategy to improve catalysts used to remove nitrogen oxides from industrial emissions. By using ethanol during catalyst preparation, the scientists significantly enhanced the performance of manganese based carbon catalysts, achieving very high pollution removal efficiency at relatively low temperatures.

Nitrogen oxides, commonly referred to as NOx, are major air pollutants produced during fossil fuel combustion in power plants and heavy industries. These gases contribute to smog formation, acid rain, and environmental and health problems. One of the most widely used technologies to control these emissions is ammonia selective catalytic reduction, which converts NOx into harmless nitrogen and water.

However, conventional catalysts used in this process often require high operating temperatures, typically between 300 and 400 degrees Celsius. In many industrial sectors such as steel manufacturing, cement production, and glass processing, exhaust gases are much cooler. This temperature mismatch reduces the efficiency of current technologies and often requires additional energy to reheat the gases.

To address this challenge, researchers developed a new preparation method for manganese oxide supported on activated carbon, a material known for its large surface area and strong adsorption capacity. The key innovation involved using ethanol instead of water during the catalyst impregnation process.

The study showed that ethanol improves the interaction between the manganese precursor and the carbon support. Because ethanol has lower polarity and surface tension than water, it spreads more easily across the carbon surface and penetrates the pores more effectively. This allows the active manganese oxide species to disperse more uniformly throughout the catalyst structure.

“Our goal was to improve the distribution of active catalytic components on the carbon surface,” said lead researcher Donghong Nan. “Using ethanol as the impregnation solvent helped us achieve much more uniform dispersion, which is essential for high catalytic performance.”

The researchers combined the ethanol assisted impregnation with a carefully controlled low temperature calcination process. This step increased the amount of Mn4+, a highly active manganese oxidation state known to play a critical role in the catalytic reduction of nitrogen oxides.

Laboratory tests showed that the optimized catalyst achieved impressive performance. At a reaction temperature of only 150 degrees Celsius and a gas hourly space velocity of 20,000 per hour, the catalyst reached a nitrogen oxide conversion efficiency of 96.3 percent. This was significantly higher than the 82.9 percent efficiency achieved by catalysts prepared using water as the solvent.

“The improvement was striking,” said corresponding author Kai Li. “Simply changing the solvent used during preparation led to a major increase in catalytic activity.”

The study also identified the optimal preparation conditions. The best performance was obtained when the catalyst contained eight percent manganese and was calcined in air at 200 degrees Celsius. Under these conditions the catalyst exhibited a high proportion of active Mn4+ species and strong surface oxygen activity, both of which are crucial for promoting the catalytic reaction.

Another advantage of the method is its practicality. The preparation process requires no complex equipment and can be easily integrated into existing catalyst production systems.

According to the researchers, the new approach could help industries reduce nitrogen oxide emissions more efficiently while lowering energy consumption. The catalyst is particularly promising for applications where exhaust temperatures are relatively low and conventional high temperature catalysts are less effective.

The team believes that the strategy of tailoring solvent properties during catalyst preparation could also inspire new designs for other environmental catalysts.

“This work demonstrates that subtle changes in catalyst preparation can lead to significant improvements in environmental performance,” Nan said. “It opens new possibilities for designing more efficient low temperature pollution control technologies.”

Journal reference: Nan D, Xie J, Wu T, Niu Q, Zhang X, et al. 2026. Preparation and performance evaluation of a novel ethanol-enhanced Mn-modified carbon-based deNOx catalyst. Sustainable Carbon Materials 2: e009 doi: 10.48130/scm-0026-0009

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