Open Access

ARTICLE

Experimental Research on Mercury Catalytic Oxidation over Ce Modified SCR Catalyst

Yadi Qin, Qiyu Weng, Yuqun Zhuo^*

Key Laboratory for Thermal Science and Power Engineering of the Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing, 100084, China

* Corresponding Author: Yuqun Zhuo. Email:

(This article belongs to the Special Issue: Advancement of Understanding of PM_2.5 and Hg Emissions and Their Control Technologies for Cleaner Combustion)

Energy Engineering 2022, 119(1), 35-47. https://doi.org/10.32604/EE.2022.015477

Received 24 December 2020; Accepted 29 March 2021; Issue published 22 November 2021

Abstract

In order to improve the ability of SCR catalyst to catalyze the oxidation of gaseous elemental mercury, a series of novel Ce modified SCR (Selection Catalytic Reduction, V₂O₅–WO₃/TiO₂) catalysts were prepared via two-step ultrasonic impregnation method. The performance of Ce/SCR catalysts on Hg⁰ oxidation and NO reduction as well as the catalytic mechanism on Hg⁰ oxidation was also studied. The XRD, BET measurements and XPS were used to characterize the catalysts. The results showed that the pore volume and pore size of catalyst was reduced by Ce doping, and the specific surface area decreased with the increase of Ce content in catalyst. The performance on Hg⁰ oxidation was promoted by the introduction of CeO₂.Ce₁/SCR (1%Ce, wt.%) catalyst exhibited the best Hg⁰ oxidation activity of 21.2% higher than that of SCR catalyst at 350°C, of which the NO conversion efficiency was also higher at 200–400°C. Furthermore, Ce₁/SCR showed a better H₂O resistance but a slightly weaker SO₂ resistance than SCR catalyst. The chemisorbed oxygen and weak absorbed oxygen on the surface of catalyst were increased by the addition of CeO₂. The chemisorbed oxygen and weak absorbed oxygen on the surface of catalyst were increased by the addition of CeO₂. The Ce₁/SCR possed better redox ability compared with SCR catalyst. HCl was the most effective gas responsible for the Hg⁰ oxidation, and the redox cycle (V⁴⁺ + Ce⁴⁺ ↔ V⁵⁺ + Ce³⁺) played an important role in promoting Hg⁰ oxidation.

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