Wolframite (FeWO), a typical polyoxometalate, serves as an auspicious candidate for heterogeneous catalysts, courtesy of its high chemical stability and electronic properties. However, the electron-deficient surface-active Fe species in FeWO are insufficient to cleave HO via Fe redox-mediated Fenton-like catalytic reaction. Herein, we doped Sulfur (S) atom into FeWO catalysts to refine the electronic structure of FeWO for HO activation and sulfamethoxazole (SMX) degradation. Furthermore, spin-state reconstruction on S-doped FeWO was found to effectively refine the electronic structure of Fe in the d orbital, thereby enhancing HO activation. S doping also accelerated electron transfer during the conversion of sulfur species, promoting the cycling of Fe(III) to Fe(II). Consequently, S-doped FeWO bolstered the Fenton-like reaction by nearly two orders of magnitude compared to FeWO. Significantly, the developed S-doped FeWO exhibited a remarkable removal efficiency of approximately 100% for SMX within 40 min in real water samples. This underscores its extensive pH adaptability, robust catalytic stability, and leaching resistance. The matrix effects of water constituents on the performance of S-doped FeWO were also investigated, and the results showed that a certain amount of Cl, SO, NO, HCO and PO exhibited negligible effects on the degradation of SMX. Theoretical calculations corroborate that the distinctive spin-state reconstruction of Fe center in S-doped FeWO is advantageous for HO decomposition. This discovery offers novel mechanistic insight into the enhanced catalytic activity of S doping in Fenton-like reactions and paves the way for expanding the application of FeWO in wastewater treatment.

中文翻译：

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硫掺杂诱导多金属氧酸盐 FeWO4 的形态和电子结构改性，增强去除水中有机污染物


黑钨矿 (FeWO) 是一种典型的多金属氧酸盐，由于其高化学稳定性和电子特性，成为多相催化剂的理想候选者。然而，FeWO 中的缺电子表面活性 Fe 不足以通过 Fe 氧化还原介导的类 Fenton 催化反应裂解 H2O。在此，我们将硫（S）原子掺杂到 FeWO 催化剂中，以细化 FeWO 的电子结构，用于 H2O 活化和磺胺甲恶唑（SMX）降解。此外，S掺杂的FeWO的自旋态重构可以有效地细化Fe在d轨道中的电子结构，从而增强H2O2的活化。 S掺杂还加速了硫物质转化过程中的电子转移，促进Fe(III)到Fe(II)的循环。因此，与 FeWO 相比，S 掺杂的 FeWO 将类芬顿反应增强了近两个数量级。值得注意的是，所开发的 S 掺杂 FeWO 在实际水样中对 SMX 表现出约 100% 的显着去除效率，在 40 分钟内。这凸显了其广泛的 pH 适应性、强大的催化稳定性和抗浸出性。还研究了水成分对S掺杂FeWO性能的基体影响，结果表明一定量的Cl、SO、NO、HCO和PO对SMX的降解影响可以忽略不计。理论计算证实，掺硫 FeWO 中 Fe 中心独特的自旋态重构有利于 H2O 分解。这一发现为类芬顿反应中硫掺杂增强催化活性提供了新的机制见解，并为扩大 FeWO 在废水处理中的应用铺平了道路。