Mitigating SO2 poisoning during CO oxidation over Pt/Al2O3 catalysts via sulfur spillover from highly under-coordinated platinum to the Al2O3 support

IF 4.8 2区化学 Q2 CHEMISTRY, PHYSICAL

Applied Catalysis A: General Pub Date : 2025-09-17 DOI:10.1016/j.apcata.2025.120580

Xiao Yang , Heying Zhao , Aiyong Wang , Wangcheng Zhan , Yanglong Guo , Li Wang , Xuan Tang , Yun Guo

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引用次数: 0

Abstract

SO₂ in the sintering flue gas severely inhibits the CO oxidation performance of commercial Pt/Al₂O₃ catalysts. However, the major poisoning mechanism of SO₂ on Pt/Al₂O₃ in CO oxidation in the presence of H₂O remains to be elucidated. Here, Pt/Al₂O₃ was pretreated with different reducing atmospheres at high temperatures. Among these, the catalyst pretreated with a CO atmosphere at 600 °C (denoted as Pt/Al₂O₃-CO-600) exhibited superior CO oxidation performance and enhanced sulfur resistance in the presence of both H₂O and SO₂. The combination of XPS, HAADF-STEM, TG-MS, SO₂ oxidation test, and in-situ DRIFTS reveal that the Pt species on Pt/Al₂O₃-CO-600 transformed from Pt oxide clusters to metallic Pt nanoparticles. This transformation enhanced SO₂ adsorption and reactivity, leading to increased sulfate accumulation. Despite the high SO₂ reactivity and sulfate content, in-situ DRIFTS revealed that the CO reaction of Pt/Al₂O₃-CO-600 was less hindered by SO₂ and the sulfated Al₂O₃. This is attributed to the high ratio of the under-coordinated (UC) Pt sites in Pt/Al₂O₃-CO-600, which promotes the reaction intermediates spillover from Pt site to Al₂O₃ compared to the Pt/Al₂O₃. This phenomenon was positively correlated with the sulfur resistance of reduced catalysts. Accordingly, the UC site contributes to the spillover of sulfate intermediate (H₂SO₄), reducing the CO reactivity loss of Pt/Al₂O₃ due to the intermediate coverage. This study elucidates that the primary poisoning pathway of Pt/Al₂O₃ in the presence of H₂O and SO₂ is the difficulty of sulfate intermediate spillover.

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通过硫从高度欠配位铂向Al2O3载体的溢出，减轻Pt/Al2O3催化剂上CO氧化过程中的SO2中毒

烧结烟气中的SO2严重抑制了Pt/Al2O3商用催化剂的CO氧化性能。然而，在H2O存在的CO氧化条件下，SO2对Pt/Al2O3的主要中毒机制仍有待阐明。本文采用不同的还原气氛对Pt/Al2O3进行高温预处理。其中，在600℃CO气氛下预处理的催化剂（记为Pt/Al2O3-CO-600）在H2O和SO2存在下均表现出优异的CO氧化性能和抗硫性能。结合XPS、HAADF-STEM、TG-MS、SO2氧化测试和原位漂移等方法，发现Pt/Al2O3-CO-600表面的Pt由氧化Pt团簇转变为金属Pt纳米颗粒。这种转变增强了SO2的吸附和反应性，导致硫酸盐积累增加。尽管Pt/Al2O3-CO-600具有较高的SO2反应活性和硫酸盐含量，但原位漂移显示，SO2和硫酸化Al2O3对Pt/Al2O3-CO-600的CO反应影响较小。这是由于Pt/Al2O3- co -600中欠配位（UC） Pt位点的比例高，与Pt/Al2O3相比，这促进了反应中间体从Pt位点向Al2O3的溢出。这一现象与还原催化剂的耐硫性呈正相关。因此，UC位点有助于硫酸盐中间体（H2SO4）的溢出，减少Pt/Al2O3因中间体覆盖而造成的CO反应性损失。本研究阐明了Pt/Al2O3在H2O和SO2存在下的主要中毒途径是硫酸盐中间溢出困难。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Applied Catalysis A: General 化学-环境科学

CiteScore

9.00

自引率

5.50%

发文量

415

审稿时长

24 days

期刊介绍： Applied Catalysis A: General publishes original papers on all aspects of catalysis of basic and practical interest to chemical scientists in both industrial and academic fields, with an emphasis onnew understanding of catalysts and catalytic reactions, new catalytic materials, new techniques, and new processes, especially those that have potential practical implications. Papers that report results of a thorough study or optimization of systems or processes that are well understood, widely studied, or minor variations of known ones are discouraged. Authors should include statements in a separate section "Justification for Publication" of how the manuscript fits the scope of the journal in the cover letter to the editors. Submissions without such justification will be rejected without review.