The Unique CO Activation Effects for Boosting NH3 Selective Catalytic Oxidation over CuO-CeO2
Yong Liao1, Zhisong Liu1, Zihao Li1
1School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
Environmental Science & Technology
|July 11, 2022
Summary
Carbon monoxide (CO) surprisingly enhances ammonia (NH₃) selective catalytic oxidation (NH₃-SCO) over CuO-CeO₂ catalysts. This finding is crucial for simultaneously removing pollutants from flue gases, improving industrial emission control.
Area of Science:
- Environmental Catalysis
- Flue Gas Treatment
- Pollutant Oxidation
Background:
- Ammonia (NH₃) slip is a significant concern in flue gases post-denitrification.
- Simultaneous catalytic removal of NH₃ and carbon monoxide (CO) is an emerging challenge in deep flue gas treatment.
- CO was previously thought to hinder NH₃ selective catalytic oxidation (NH₃-SCO) due to active species competition.
Purpose of the Study:
- To investigate the effect of CO on NH₃-SCO over CuO-CeO₂ catalysts.
- To elucidate the underlying mechanism of CO's influence on NH₃ oxidation.
- To explore the potential of CO in promoting simultaneous catalytic oxidation of coexisting pollutants.
Main Methods:
- Experimental catalytic oxidation of NH₃ and CO over CuO-CeO₂.
- Varied CO concentrations and reaction temperatures (180-300 °C).
- In-situ mechanistic studies involving redox cycles and active oxygen species analysis.
Main Results:
- CO significantly promoted NH₃-SCO, contrary to expectations.
- NH₃ conversion rates increased linearly with CO concentration.
- CuO-CeO₂ catalyst demonstrated enhanced performance, with NH₃ conversion accelerating by 2.8 times at 220 °C with 10,000 ppm CO.
- Mechanism revealed CO actuation of Cu⁺/Cu²⁺ redox cycle, boosting active isolated oxygen atoms (Oᵢ) generation.
- CuO species facilitated NH₃ dehydrogenation, mitigating competition and stabilizing promotion via i-SCR.
Conclusions:
- CO can act as a promoter, not an inhibitor, for NH₃-SCO over CuO-CeO₂.
- The Cu-O-Ce solid solution and CuO species play synergistic roles in CO and NH₃ oxidation.
- This study highlights a novel approach for simultaneous pollutant removal in industrial flue gases.
Keywords:
CO oxidationCO utilizationmultipollutant simultaneous controlslip NH3 removalsynergistic effectMore Related Videos
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