Low-vanadium and high-activity SCR catalyst for low-temperature denitrification: Influence of vanadium precursor and surface vanadium concentration

Q3 Energy

燃料化学学报 Pub Date : 2024-11-01 DOI:10.1016/S1872-5813(24)60467-6

Xi TIAN , Peng YE , Qilong WU , Shangchao XIONG , Lina GAN , Jianjun CHEN

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引用次数: 0

Abstract

Nitrogen oxides (NO_x), as the main pollutants of air pollution, cause serious harm to the ecological environment and human health. SCR technology is widely used as the most effective method for treating NO_x. The core of SCR technology is SCR catalyst. The reaction temperature of traditional commercial catalysts is difficult to reach the optimal operating temperature range, so expanding the temperature window of V₂O₅/TiO₂ catalysts to the low-temperature region while reducing vanadium loading is a key issue to be solved. A series of V₂O₅/TiO₂ catalysts with different vanadium precursors and different vanadium loadings were prepared by solid-phase synthesis method. The physicochemical properties of the catalyst were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, temperature programmed desorption of ammonia and temperature programmed reduction of hydrogen. The denitrification activity of the catalyst was evaluated in a fixed bed reactor. The catalysts prepared with vanadyl oxalate (VOC₂O₄·xH₂O) and vanadyl acetylacetonate (VO(acac)₂) as vanadium precursors with a vanadium loading of 5% exhibited the highest denitrification activity, with a stable NO_x conversion of 100% within the temperature range of 200–350 °. Compared with the catalysts prepared with ammonium metavanadate (NH₄VO₃) and vanadyl sulfate (VOSO₄·xH₂O) as the vanadium precursors, the maximum activity temperature of VOC₂O₄-V5Ti and VO(acac)₂-V5Ti shifted towards the low-temperature region by about 150 °. Furthermore, the denitrification activity of catalyst with a low vanadium content (1%) prepared using VO(acac)₂ precursor was even higher than that of catalyst with a high vanadium content (6%) prepared using NH₄VO₃ precursor. Using VOC₂O₄ and VO(acac)₂ as vanadium precursors could effectively regulate the active sites and polymeric states on the catalysts, and promote the interaction of V atoms with different valence states to form more reductive V species (V⁴⁺), thus exhibiting excellent SCR reactivity. This study provided an effective method for the preparation of low-vanadium and high-activity denitrification catalysts at low temperatures.

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用于低温脱硝的低钒高活性 SCR 催化剂：钒前驱体和表面钒浓度的影响

氮氧化物（NOx）作为大气污染的主要污染物，对生态环境和人类健康造成严重危害。选择性催化还原（SCR）技术作为处理氮氧化物最有效的方法被广泛应用。SCR 技术的核心是 SCR 催化剂。传统商用催化剂的反应温度很难达到最佳工作温度范围，因此在降低钒负载的同时，将 V2O5/TiO2 催化剂的温度窗口扩大到低温区域是亟待解决的关键问题。本研究采用固相合成法制备了一系列不同钒前驱体和不同钒负载量的 V2O5/TiO2 催化剂。通过 X 射线衍射、X 射线光电子能谱、氨的温程解吸和氢的温程还原分析了催化剂的理化性质。在固定床反应器中对催化剂的脱硝活性进行了评估。以草酸钒（VOC2O4-xH2O）和乙酰丙酮酸钒（VO(acac)2）为钒前体制备的催化剂（钒负载量为 5%）脱硝活性最高，在 200-350 ° 的温度范围内氮氧化物转化率稳定在 100%。与以偏钒酸铵（NH4VO3）和硫酸钒（VOSO4-xH2O）为钒前体制备的催化剂相比，VOC2O4-V5Ti 和 VO（acac）2-V5Ti 的最高活性温度向低温区移动了约 150 °。此外，使用 VO(acac)2 前驱体制备的低钒含量（1%）催化剂的脱硝活性甚至高于使用 NH4VO3 前驱体制备的高钒含量（6%）催化剂。使用 VOC2O4 和 VO(acac)2 作为钒前驱体，可以有效调节催化剂上的活性位点和聚合态，促进不同价态的钒原子相互作用，形成还原性更强的钒物种（V4+），从而表现出优异的 SCR 反应活性。该研究为低温制备低钒高活性脱硝催化剂提供了一种有效的方法。

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来源期刊

燃料化学学报 Chemical Engineering-Chemical Engineering (all)

CiteScore

2.80

自引率

0.00%

发文量

5825

期刊介绍： Journal of Fuel Chemistry and Technology (Ranliao Huaxue Xuebao) is a Chinese Academy of Sciences(CAS) journal started in 1956, sponsored by the Chinese Chemical Society and the Institute of Coal Chemistry, Chinese Academy of Sciences(CAS). The journal is published bimonthly by Science Press in China and widely distributed in about 20 countries. Journal of Fuel Chemistry and Technology publishes reports of both basic and applied research in the chemistry and chemical engineering of many energy sources, including that involved in the nature, processing and utilization of coal, petroleum, oil shale, natural gas, biomass and synfuels, as well as related subjects of increasing interest such as C1 chemistry, pollutions control and new catalytic materials. Types of publications include original research articles, short communications, research notes and reviews. Both domestic and international contributors are welcome. Manuscripts written in Chinese or English will be accepted. Additional English titles, abstracts and key words should be included in Chinese manuscripts. All manuscripts are subject to critical review by the editorial committee, which is composed of about 10 foreign and 50 Chinese experts in fuel science. Journal of Fuel Chemistry and Technology has been a source of primary research work in fuel chemistry as a Chinese core scientific periodical.