Insight into the effect of morphology on catalytic performance of porous CeO2 nanocrystals for H2S selective oxidation

IF 20.2 1区化学 Q1 CHEMISTRY, PHYSICAL

Applied Catalysis B: Environmental Pub Date : 2019-09-05 DOI:10.1016/j.apcatb.2019.04.014

Xiaohai Zheng , Yanli Li , Linyan Zhang , Lijuan Shen , Yihong Xiao , Yongfan Zhang , Chaktong Au , Lilong Jiang

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引用次数: 179

Abstract

Shape-specific CeO₂ nanocrystals (rods, cubes, spheres and nanoparticles) with well-defined crystal facets and hierarchically porous structure were successfully synthesized and used as model catalysts to study the structure-dependent behavior and reaction mechanism for H₂S selective oxidation over ceria-based catalysts. It is deduced that the defect sites and base properties of CeO₂ are intrinsically determined by the surface crystal facets. Among the nanocrystals, CeO₂ nanorods with well-defined {110} and {100} crystal facets exhibits superb catalytic activity and sulfur selectivity. The high reactivity for H₂S selective oxidation is attributed to the high concentration of surface oxygen vacancies which are beneficial for the conversion of lattice oxygen to active oxygen species. Besides, the presence of hierarchically porous structure of CeO₂ nanorods hinders the formation of SO₂ and sulfate, ensuring good sulfur selectivity and catalyst stability. Through a combined approach of density-functional theory (DFT) calculations and in situ DRIFTS investigation, the plausible reaction mechanism and nature of active sites for H₂S selective oxidation over CeO₂ catalysts have been revealed.

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形貌对多孔CeO2纳米晶催化H2S选择性氧化性能影响的研究

成功合成了具有明确晶面和分层多孔结构的形状特异的CeO2纳米晶体(棒状、立方体、球形和纳米颗粒)，并将其作为模型催化剂，研究了氧化铈基催化剂对H2S选择性氧化的结构依赖行为和反应机理。推导出CeO2的缺陷位置和基体性能本质上是由表面晶面的形貌决定的。纳米晶中，{110}和{100}晶面清晰的CeO2纳米棒表现出优异的催化活性和硫选择性。H2S选择性氧化反应活性高是由于表面氧空位浓度高，有利于晶格氧向活性氧的转化。此外，CeO2纳米棒的分层多孔结构的存在阻碍了SO2和硫酸盐的形成，保证了良好的硫选择性和催化剂稳定性。通过密度泛函理论(DFT)计算和原位DRIFTS研究相结合的方法，揭示了H2S在CeO2催化剂上选择性氧化的可能反应机理和活性位点的性质。

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来源期刊

Applied Catalysis B: Environmental 环境科学-工程：化工

CiteScore

38.60

自引率

6.30%

发文量

1117

审稿时长

24 days

期刊介绍： Applied Catalysis B: Environment and Energy (formerly Applied Catalysis B: Environmental) is a journal that focuses on the transition towards cleaner and more sustainable energy sources. The journal's publications cover a wide range of topics, including: 1.Catalytic elimination of environmental pollutants such as nitrogen oxides, carbon monoxide, sulfur compounds, chlorinated and other organic compounds, and soot emitted from stationary or mobile sources. 2.Basic understanding of catalysts used in environmental pollution abatement, particularly in industrial processes. 3.All aspects of preparation, characterization, activation, deactivation, and regeneration of novel and commercially applicable environmental catalysts. 4.New catalytic routes and processes for the production of clean energy, such as hydrogen generation via catalytic fuel processing, and new catalysts and electrocatalysts for fuel cells. 5.Catalytic reactions that convert wastes into useful products. 6.Clean manufacturing techniques that replace toxic chemicals with environmentally friendly catalysts. 7.Scientific aspects of photocatalytic processes and a basic understanding of photocatalysts as applied to environmental problems. 8.New catalytic combustion technologies and catalysts. 9.New catalytic non-enzymatic transformations of biomass components. The journal is abstracted and indexed in API Abstracts, Research Alert, Chemical Abstracts, Web of Science, Theoretical Chemical Engineering Abstracts, Engineering, Technology & Applied Sciences, and others.