Fe₂O₃ as photoanode photoelectrocatalytic (PEC) CH₃OH conversion is a promising approach for industrial preparation of high value-added HCHO. However, the conversion efficiency is limited by its poor charge separation and sluggish oxidation mechanism. This study reports a direct Z-scheme system consisting of 1D nanotubes oxygen-deficient a-Fe₂O₃ and g-C₃N₄ (ZOF@CN NTs) with great enhancement of PEC CH₃OH oxidation to HCHO activity. The ZOF@CN NTs presents a CH₃OH oxidation photocurrent density of 1.05 mA cm⁻² at 0.6 V vs Ag/AgCl, 5.25 times than that of oxygen-deficient a-Fe₂O₃ alone (0.20 mA cm⁻²), and HCHO selectivity of 81.5%. Combining by UV–vis, UPS, PL spectroscopy, PEC performance and density functional theory calculations, the mechanism of CH₃OH oxidation to HCHO on Z-scheme ZOF@CN NTs photoanode was found along following pathway: CH₃OH*–CH₃O*- CH₂O* –CH₂O (g), which is starting from the O–H bond scission and then followed by C−H scission. The CH₃O* via the C–H bond scission to form CH₂O* is the key step for the reaction, and N atoms from g-C₃N₄ with higher electronegativity compared with O atoms, which is useful for C–H bond scission. This work serves as a solid foundation for understanding Fe₂O₃-based Z-scheme system photoanodes for CH₃OH oxidation to HCHO.

Fe ₂ O ₃作为光阳极光电催化（PEC）CH ₃ OH的转化是工业制备高附加值HCHO的有前途的方法。然而，转化效率受到其不良的电荷分离和缓慢的氧化机理的限制。这项研究报告了一种直接的Z方案系统，该体系由缺氧的一维纳米管a -Fe ₂ O ₃和g -C ₃ N ₄（ZOF @ CN NTs）组成，极大地增强了PEC CH ₃ OH氧化成HCHO的活性。ZOF @ CN NTs在0.6 V下的CH ₃ OH氧化光电流密度为1.05 mA cm ^-2与Ag / AgCl相比，是缺氧的-Fe ₂ O ₃单独（0.20 mA cm ^-2）的5.25倍，HCHO选择性为81.5％。结合UV-vis，UPS，PL光谱，PEC性能和密度泛函理论计算，通过以下途径发现了Z型ZOF @ CN NTs光阳极上CH ₃ OH氧化为HCHO的机理：CH ₃ OH * –CH ₃ O *-CH ₂ O * –CH ₂ O（g），它是从O–H键断裂开始，然后是CH–H断裂。的CH ₃经由CH键断裂以形成2 CH 2 O * ₂ ○*是该反应的关键步骤，并且从N原子g -C ₃ N ₄具有比O原子更高的电负性，这对于C–H键断裂是有用的。这项工作为理解基于Fe ₂ O ₃的Z方案体系光阳极，将CH ₃ OH氧化为HCHO奠定了坚实的基础。