Asymmetrically modified titanium(IV) oxide particles having both hydrophobic and hydrophilic parts of their surfaces for liquid-liquid dual-phase photocatalytic reactions
Asymmetrically modified titanium(IV) oxide particles having both hydrophobic and hydrophilic parts of their surfaces for liquid-liquid dual-phase photocatalytic reactions
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表面具有疏水性和亲水性部分的不对称改性氧化钛（IV）颗粒用于液-液双相光催化反应
DOI：
10.1016/j.apcata.2004.01.004
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发表时间：
2004
影响因子：
5.5
通讯作者：
B. Ohtani
中科院分区：
文献类型：
--
作者：
S. Ikeda;Y. Kowata;K. Ikeue;M. Matsumura;B. Ohtani
利用烷基硅基对钛(IV)氧化物(TiO2光催化剂)颗粒外表面进行部分改性，制备了组装在液-液两相混合物相界面的TiO2光催化剂颗粒。通过对样品的碳和灰分的元素分析以及在乙醇水溶液中的可浮性，估算了烷基硅基的平均表面覆盖率。结果表明，不对称改性样品的疏水性-亲水性与完全覆盖烷基硅基的样品相当。不对称或完全烷基硅基修饰的二氧化钛颗粒在没有搅拌的情况下对苯氧化生成苯酚表现出光催化活性，而裸露的二氧化钛需要机械搅拌才能诱导光催化反应。然而，由于表面烷基硅基的光催化分解，长时间的照射在水层中析出了一些表面修饰的颗粒。以包覆多孔二氧化硅(SiO_2)的TiO_2粒子为原料，提高了其光稳定性。与完全烷基硅基修饰的SiO_2包覆的TiO_2粒子(o-Si/Ti)相比，非对称修饰的SiO_2-TiO_2粒子(w/o-Si/Ti)对苯氧化的光催化活性略高。另一方面，在苯-水混合物和脱氧条件下的水溶液中，两种粒子的光催化放氢活性有显著差异；w/o-Si/Ti的光催化活性是o-Ti/Si的两倍多，这可能是因为w/o-Si/Ti与水和有机相的有效接触，而o-Si/Ti很难与水相接触。
Titanium(IV) oxide (TiO2)-based photocatalyst particles assembled at the phase boundary of a liquid–liquid dual-phase mixture were prepared by partial modification of the external surface of each particle with alkylsilyl groups. The average surface coverage of alkylsilyl groups was estimated by elemental analyses of carbon and ash components of the samples and floatability on aqueous ethanol solutions. Results revealed that the hydrophobicity–hydrophilicity of asymmetrically modified samples was comparable to that of samples fully covered with alkylsilyl groups. TiO2particles asymmetrically or fully modified with alkylsilyl groups showed photocatalytic activity for benzene oxidation to produce phenol from an aerated benzene–water dual-phase mixture even without agitation, while bare TiO2required mechanical agitation to induce the photocatalytic reaction. However, prolonged irradiation precipitated some of the surface-modified particles in the aqueous layer due to photocatalytic decomposition of surface alkylsilyl groups. The photostability was improved by employment of TiO2particles coated with porous silica (SiO2) as a starting material. Compared with the SiO2-coated TiO2particles fully modified with alkylsilyl groups (o-Si/Ti), the asymmetrically modified SiO2–TiO2particles (w/o-Si/Ti) showed slightly higher photocatalytic activity for benzene oxidation. On the other hand, a notable difference between the two types of particles was observed in photocatalytic hydrogen evolution in the presence of sacrificial donors from a benzene–water mixture and from an aqueous solution under deaerated conditions; w/o-Si/Ti showed the activity more than two-fold greater than that of o-Ti/Si, presumably because of efficient contact of w/o-Si/Ti with both aqueous and organic phases compared with o-Si/Ti, which was rather difficult to contact with the aqueous phase.
DOI：
10.1524/zpch.1999.211.part_1.117
发表时间：
2021-07
期刊：
Zeitschrift für Physikalische Chemie
影响因子：
--
作者：
J. Strunk;F. Osterloh;J. Hofmann
通讯作者：
J. Strunk;F. Osterloh;J. Hofmann
影响因子：
5.5
作者：
Ohno, T;Tokieda, K;Matsumura, M
通讯作者：
Matsumura, M