Fe₂O₃, as an earth-abundant photocatalyst for water purification, has attracted great attention. However, the high-spin Fe^III in traditional Fe₂O₃ restricts its catalytic performance. In this work, based on the nanocrystal size alteration strategy, cubic Fe₂O₃ nanoclusters (3–4 nm) with low-spin Fe^III were successfully anchored on six-fold cavities of the supramolecular condensed g-C₃N₄ rod (FCN) through the impregnation-coprecipitation method. FCN showed high photocatalytic activity, as the d band center of Fe 3d orbital (−1.79 eV) in low-spin Fe^III shifted closer to Femi level, generating a weaker antibonding state. Then, the enhanced bonding state strengthened the interaction between Fe and O, further accelerating the charge carrier separation and enhancing its ability to capture OH⁻. Thus, low-spin Fe^III enhanced the production of dominant reactive oxygen species (•OH/•O₂⁻), promoting diclofenac photocatalytic degradation under solar light, with a kinetic rate constant (0.206 min⁻¹) of ~5 times compared with that of pristine g-C₃N₄.

Fe ₂ O ₃作为一种储量丰富的水净化光催化剂，引起了人们的广泛关注。然而，传统Fe ₂ O ₃中的高自旋Fe ^III限制了其催化性能。在这项工作中，基于纳米晶体尺寸改变策略，具有低自旋 Fe ^{III的立方 Fe} ₂ O _{3纳米团簇（3-4 nm）成功地锚定在超分子凝聚 gC 3} N ₄棒（FCN）的六倍腔上。通过浸渍-共沉淀法。FCN 显示出高光催化活性，作为低自旋 Fe ^{III中 Fe 3d 轨道 (-1.79 eV) 的 d 带中心}移近 Femi 能级，产生较弱的反键态。然后，增强的键合状态加强了 Fe 和 O 之间的相互作用，进一步加速了电荷载流子的分离并增强了其捕获 OH ^-的能力。因此，低自旋 Fe ^III增强了主要活性氧物质 (•OH/•O ₂ ^- ) 的产生，促进了双氯芬酸在太阳光下的光催化降解，其动力学速率常数 (0.206 min ^-1 ) 为约 5 倍的原始 gC ₃ N ₄。