Sattayarak Sirachat, Vas-Umnuay Paravee
Center of Excellence in Particle and Material Processing Technology, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University Bangkok 10330 Thailand
Nanoscale Adv. 2025 Mar 24;7(10):3028-3037. doi: 10.1039/d4na01032a. eCollection 2025 May 13.
Photoelectrochemical (PEC) conversion presents a viable strategy for reducing the external bias required in conventional electrochemical methods for organic molecule valorization. However, the efficiency of PEC processes is largely dependent on photoelectrode characteristics, specifically light absorption and charge transport properties. These properties are crucial for efficient generation of charge carriers and photocurrent for driving reactions. Herein, we report efficient PEC conversion of benzyl alcohol to benzaldehyde using tailored TiO photoanodes of both compact and mesoporous film morphologies in a continuous-flow PEC cell. Notably, our PEC flow cell was designed on a microscale to facilitate superior mass transfer. Parameters such as applied potential, electrolyte flow rate, channel width, and photoanode characteristics were systematically investigated to elucidate their impact on conversion efficiency and selectivity in the PEC oxidation process. The results indicated that at an applied potential of 3.5 V and an electrolyte flow rate of 0.05 ml min, the microchannel with a width of 0.1 mm, which corresponds to a residence time of 1.6 min, achieved benzyl alcohol conversion exceeding 80%. Comparative analyses with traditional batch H-cells revealed over a fivefold increase in benzyl alcohol conversion in the microchannel flow cell with the mesoporous TiO photoanode. Additionally, the flow cell exhibited approximately threefold higher benzaldehyde selectivity compared to batch reactors employing the compact TiO photoanode. Overall, this work demonstrates the potential of continuous-flow microchannels with tailored photoanodes for achieving efficient and rapid PEC conversions, promising advancements in sustainable organic transformations.
光电化学（PEC）转化为降低传统电化学方法中有机分子增值所需的外部偏压提供了一种可行的策略。然而，PEC过程的效率在很大程度上取决于光电极特性，特别是光吸收和电荷传输特性。这些特性对于有效产生驱动反应的电荷载流子和光电流至关重要。在此，我们报告了在连续流动PEC电池中使用具有致密和介孔薄膜形态的定制TiO光阳极将苯甲醇高效PEC转化为苯甲醛。值得注意的是，我们的PEC流动电池是在微观尺度上设计的，以促进优异的传质。系统研究了诸如施加电位、电解液流速、通道宽度和光阳极特性等参数，以阐明它们对PEC氧化过程中转化效率和选择性的影响。结果表明，在施加电位为3.5 V和电解液流速为0.05 ml min时，宽度为0.1 mm的微通道（对应于1.6 min的停留时间）实现了超过80%的苯甲醇转化率。与传统间歇式H型电池的对比分析表明，使用介孔TiO光阳极的微通道流动电池中苯甲醇转化率提高了五倍以上。此外，与使用致密TiO光阳极的间歇式反应器相比，流动电池的苯甲醛选择性高出约三倍。总体而言，这项工作展示了具有定制光阳极的连续流动微通道在实现高效快速PEC转化方面的潜力，有望在可持续有机转化方面取得进展。
