Kunthakudee Naphaphan, Puangpetch Tarawipa, Ramakul Prakorn, Serivalsatit Karn, Ponchio Chatchai, Hunsom Mali
Department of Chemical Engineering, Faculty of Engineering, Mahidol University Phuttamonthon 4 Road Nakhon Pathom 73170 Thailand
Department of Chemical Engineering, Faculty of Engineering and Industrial Technology, Silpakorn University Nakhon Pathom 73000 Thailand.
RSC Adv. 2024 Aug 2;14(33):24213-24225. doi: 10.1039/d4ra04284k. eCollection 2024 Jul 26.
An ultra-fast green synthesis of defective titanium dioxide (TiO) photocatalysts was conducted by the microwave-assisted method using l-ascorbic acid (l-As) as a reducing agent. Effect of l-As concentrations on the chemical-, optical- and photoelectrochemical properties as well as the photocatalytic performance towards the hydrogen (H) production was explored. The obtained TiO nanoparticles (NPs) illustrated the brown fine powders with different brownness levels depending on the concentrations of l-As. A high l-As concentration provided a high brownness of TiO NPs with a high generation of Ti defects and oxygen vacancies (O), which can extend the light absorption towards the visible and near-infrared regions, suppress the recombination rate of electron-hole pairs, promote the photocurrent response and minimize the interface charge transfer resistance. An appropriate quantity of generated defects and good porous properties played a crucial role in photocatalytic H production. Under fluorescence illumination, the sample synthesized with a TiO and l-As weight ratio of 1 : 0.25 (PAs0.25) exhibited the highest H production rate (∼162 μmol g h in the presence of 1 wt% Au co-catalyst) with a slight drop (∼8.2%) after the 5th use (15 h). The synthesis method proposed in this work provides a new insight to an ultra-fast synthesis of defective TiO NPs using an eco-friendly chemical precursor under non-severe conditions.
采用微波辅助法，以L-抗坏血酸（L-As）作为还原剂，对缺陷型二氧化钛（TiO₂）光催化剂进行了超快速绿色合成。研究了L-As浓度对其化学、光学和光电化学性质以及光催化产氢性能的影响。所制备的TiO₂纳米颗粒（NPs）呈现出棕色细粉，其棕色程度因L-As浓度而异。高浓度的L-As可使TiO₂ NPs具有较高的棕色度，同时产生大量的Ti缺陷和氧空位（O），这可以将光吸收扩展到可见光和近红外区域，抑制电子-空穴对的复合率，促进光电流响应，并使界面电荷转移电阻最小化。适量的缺陷生成和良好的多孔性能在光催化产氢中起着关键作用。在荧光照射下，TiO₂与L-As重量比为1:0.25合成的样品（PAs0.25）表现出最高的产氢速率（在1 wt% Au助催化剂存在下约为162 μmol g⁻¹ h⁻¹），在第5次使用（15 h）后略有下降（约8.2%）。本文提出的合成方法为在非苛刻条件下使用环保型化学前驱体超快速合成缺陷型TiO₂ NPs提供了新的思路。
