Mesoporous Anatase–Brookite TiO2: Surface Acidity and Performance in Isopropanol Catalytic Dehydration

IF 2.3 4区化学 Q3 CHEMISTRY, PHYSICAL

Catalysis Letters Pub Date : 2025-08-04 DOI:10.1007/s10562-025-05131-4

Nabil En.nami, Abdelhafid Ait Blal, Jaafar EL Fallah, Guillaume Clet, Konstantin Hadjiivanov, Françoise Maugé, Abdelakrim Aboulayt

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Abstract

The adsorption, catalytic and photocatalytic properties of titania strongly depend on its phase composition, morphology and the presence of impurities. In this work, we report new data on the surface acidity and catalytic performance of anatase–brookite TiO₂ and compare them with data for a commercial anatase–rutile system (TiO₂ Degussa P25). Pure titania was synthesized by the sol-gel method using titanium (IV) isopropoxide as a precursor. It consisted of anatase–brookite nanoparticles, as revealed by XRD, Raman spectroscopy and SEM. The sample has a monomodal, mesoporous structure with well-defined pore size around 7.5 nm. FTIR spectroscopy highlighted the impact of the bulk composition on the surface by identifying different hydroxyl groups associated with anatase and brookite TiO₂. For both titania samples, the adsorption of 2,6-dimethylpyridine showed the existence of Lewis acid sites and two types of Brønsted acid sites of different strengths, but the density of all types of acid sites was much higher for the synthesized TiO₂ polymorph. Anatase–brookite TiO₂ is more active and selective in the dehydration of isopropanol to propene than TiO₂ Degussa P25, which is associated with the significantly higher surface acidity of this catalyst.

Graphical Abstract

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介孔锐钛矿-板钛矿TiO2：表面酸度及异丙醇催化脱水性能

二氧化钛的吸附、催化和光催化性能在很大程度上取决于其相组成、形态和杂质的存在。在这项工作中，我们报告了锐钛矿-绿钛矿TiO2表面酸度和催化性能的新数据，并将其与商业锐钛矿-金红石体系（TiO2 Degussa P25）的数据进行了比较。以异丙醇钛为前驱体，采用溶胶-凝胶法制备了纯二氧化钛。通过XRD、拉曼光谱和扫描电镜分析，发现其为锐钛矿-板钛矿纳米颗粒。样品具有单模、介孔结构，孔径在7.5 nm左右。FTIR光谱通过识别与锐钛矿和板钛矿TiO2相关的不同羟基，突出了体组成对表面的影响。对于两种二氧化钛样品，2,6-二甲基吡啶的吸附均显示存在不同强度的Lewis酸位点和两种类型的Brønsted酸位点，但合成的TiO2多晶型中所有类型酸位点的密度都要高得多。锐钛矿型钙钛矿TiO2在异丙醇脱水制丙烯过程中比TiO2 Degussa P25具有更强的活性和选择性，这与该催化剂的表面酸度显著提高有关。图形抽象

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来源期刊

Catalysis Letters 化学-物理化学

CiteScore

5.70

自引率

3.60%

发文量

327

审稿时长

1 months

期刊介绍： Catalysis Letters aim is the rapid publication of outstanding and high-impact original research articles in catalysis. The scope of the journal covers a broad range of topics in all fields of both applied and theoretical catalysis, including heterogeneous, homogeneous and biocatalysis. The high-quality original research articles published in Catalysis Letters are subject to rigorous peer review. Accepted papers are published online first and subsequently in print issues. All contributions must include a graphical abstract. Manuscripts should be written in English and the responsibility lies with the authors to ensure that they are grammatically and linguistically correct. Authors for whom English is not the working language are encouraged to consider using a professional language-editing service before submitting their manuscripts.