Çetinkaya Sıdıka, Khamidov Gofur, Özcan Levent, Palmisano Leonardo, Yurdakal Sedat
Kimya Bölümü, Fen-Edebiyat Fakültesi, Afyon Kocatepe Üniversitesi, Ahmet Necdet Sezer Kampüsü, Afyonkarahisar, Turkey.
Biyomedikal Mühendisliği Bölümü, Mühendislik Fakültesi, Afyon Kocatepe Üniversitesi, Ahmet Necdet Sezer Kampüsü, Afyonkarahisar, Turkey.
Front Chem. 2022 May 12;10:856947. doi: 10.3389/fchem.2022.856947. eCollection 2022.
Nanotube/nanowire-structured TiO was formed on the Ti surface by an anodic oxidation method performed at different potential values (50 or 60 V) and for different times (3 or 5 h). The TiO photocatalysts were taken in powder form using the ultrasonic treatment from the Ti electrodes, calcined at different temperatures, and characterized by XRD and SEM techniques, and BET surface area analyses. Both the crystallinity and the size of the primary TiO particles increased by increasing the heat treatment temperature. While all the photocatalysts heat treated up to 500°C were only in the anatase phase, the particles heat-treated at 700°C consisted of both anatase and rutile phases. The BET specific surface area of the samples decreased drastically after heat treatment of 700°C because of partial sinterization. SEM analyses indicated that the prepared materials were structured in both nanotubes and nanowires. They were tested as photocatalysts for the selective oxidation of glycerol and 3-pyridinemethanol under UVA irradiation in water at room temperature and ambient pressure. Glyceraldehyde, 1,3-dihydroxyacetone, and formic acid were determined as products in glycerol oxidation, while the products of 3-pyridinemethanol oxidation were 3-pyridinemethanal and vitamin B. Non-nanotube/nanowire-structured commercial (Degussa P25 and Merck TiO) photocatalysts were used for the sake of comparison. Low selectivity values towards the products obtained by partial oxidation were determined for glycerol. On the contrary, higher selectivity values towards the products were obtained (total 3-pyridinemethanal and vitamin B selectivity up to ca. 90%) for the photocatalytic oxidation of 3-pyridinemethanol. TiO photocatalysts must be highly crystalline (calcined at 700°C) for effective oxidation of glycerol, while for the selective oxidation of 3-pyridinemethanol it was not necessary to obtain a high crystallinity, and the optimal heat treatment temperature was 250°C. Glycerol and its oxidation products could more easily desorb from highly crystalline and less hydroxylated surfaces, which would justifies their higher activity. The prepared photocatalysts showed lower activity than Degussa P25, but a greater selectivity towards the products found.
通过在不同电势值（50或60V）下进行不同时间（3或5小时）的阳极氧化法，在钛表面形成了纳米管/纳米线结构的二氧化钛。使用超声处理从钛电极获取粉末形式的二氧化钛光催化剂，在不同温度下煅烧，并通过XRD、SEM技术以及BET表面积分析进行表征。随着热处理温度的升高，初级二氧化钛颗粒的结晶度和尺寸均增大。虽然所有在500°C以下热处理的光催化剂仅处于锐钛矿相，但在700°C热处理的颗粒由锐钛矿相和金红石相组成。由于部分烧结，700°C热处理后样品的BET比表面积急剧下降。SEM分析表明，制备的材料呈纳米管和纳米线结构。在室温常压下的水中，在UVA辐射下，将它们作为光催化剂用于甘油和3 - 吡啶甲醇的选择性氧化测试。甘油氧化的产物确定为甘油醛、1,3 - 二羟基丙酮和甲酸，而3 - 吡啶甲醇氧化的产物为3 - 吡啶甲醛和维生素B。为了进行比较使用了非纳米管/纳米线结构的商用（德固赛P25和默克二氧化钛）光催化剂。对于甘油，对部分氧化得到的产物的选择性值较低。相反，对于3 - 吡啶甲醇的光催化氧化，对产物获得了更高的选择性值（3 - 吡啶甲醛和维生素B的总选择性高达约90%）。为了有效氧化甘油，二氧化钛光催化剂必须高度结晶（在700°C煅烧），而对于3 - 吡啶甲醇的选择性氧化，不必获得高结晶度，最佳热处理温度为250°C。甘油及其氧化产物更容易从高度结晶且羟基化程度较低的表面解吸，这可以解释它们较高的活性。所制备的光催化剂活性低于德固赛P25，但对所发现的产物具有更高的选择性。
