Department of Chemistry, Fudan University, Shanghai 200433, P. R. China.
College of Mathematics and Physics, Shanghai University of Electric Power, Shanghai 201306, China.
ACS Appl Mater Interfaces. 2023 Mar 8;15(9):11678-11690. doi: 10.1021/acsami.2c20516. Epub 2023 Feb 21.
The integration of the glycerol oxidation reaction (GOR) with the hydrogen evolution reaction in photoelectrochemical (PEC) cells is a desirable alternative to PEC water splitting since a large quantity of glycerol is easily accessible as the byproduct from the biodiesel industry. However, the PEC valorization of glycerol to the value-added products suffers from low Faradaic efficiency and selectivity, especially in acidic conditions, which is beneficial for hydrogen production. Herein, by loading bismuth vanadate (BVO) with a robust catalyst composed of phenolic ligands (tannic acid) coordinated with Ni and Fe ions (TANF), we demonstrate a modified BVO/TANF photoanode for the GOR with a remarkable Faradaic efficiency of over 94% to value-added molecules in a 0.1 M NaSO/HSO (pH = 2) electrolyte. The BVO/TANF photoanode achieved a high photocurrent of 5.26 mA·cm at 1.23 V reversible hydrogen electrode under 100 mW/cm white light irradiation for formic acid production with 85% selectivity, equivalent to 573 mmol/(m·h). Transient photocurrent and transient photovoltage techniques and electrochemical impedance spectroscopy along with intensity-modulated photocurrent spectroscopy indicated that the TANF catalyst could accelerate hole transfer kinetics and suppress charge recombination. Comprehensive mechanistic investigations reveal that the GOR is initiated by the photogenerated holes of BVO, while the high selectivity to formic acid is attributed to the selective adsorption of primary hydroxyl groups in glycerol on TANF. This study provides a promising avenue for highly efficient and selective formic acid generation from biomass in acid media PEC cells.
甘油氧化反应（GOR）与光电化学（PEC）电池中的析氢反应相结合是一种替代 PEC 水分解的理想方法，因为大量的甘油很容易作为生物柴油工业的副产物获得。然而，PEC 从甘油到附加值产品的增值转化受到法拉第效率和选择性低的困扰，特别是在有利于氢气生产的酸性条件下。在此，通过负载偏钒酸铋（BVO）与由酚配体（单宁酸）与 Ni 和 Fe 离子配位组成的强催化剂（TANF），我们展示了一种改性的 BVO/TANF 光阳极，用于 GOR，在 0.1 M NaSO/HSO（pH = 2）电解质中，对附加值分子的法拉第效率超过 94%。在 100 mW/cm 白光照射下，BVO/TANF 光阳极在 1.23 V 可逆氢电极下实现了 5.26 mA·cm 的高光电流，用于甲酸的生成，选择性为 85%，相当于 573 mmol/（m·h）。瞬态光电流和瞬态光电压技术以及电化学阻抗谱和强度调制光电流谱表明，TANF 催化剂可以加速空穴转移动力学并抑制电荷复合。综合的机理研究表明，GOR 是由 BVO 的光生空穴引发的，而甲酸的高选择性归因于甘油中的伯羟基在 TANF 上的选择性吸附。该研究为在酸性介质 PEC 电池中从生物质高效和选择性地生成甲酸提供了一个有前景的途径。
