Abstract：
Wolframite (FeWO4), 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 FeWO4 are insufficient to cleave H2O2 via Fe redox-mediated Fenton-like catalytic reaction. Herein, we doped Sulfur (S) atom into FeWO4 catalysts to refine the electronic structure of FeWO4 for H2O2 activation and sulfamethoxazole (SMX) degradation. Furthermore, spin-state reconstruction on S-doped FeWO4 was found to effectively refine the electronic structure of Fe in the d orbital, thereby enhancing H2O2 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 FeWO4 bolstered the Fenton-like reaction by nearly two orders of magnitude compared to FeWO4. Significantly, the developed S-doped FeWO4 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 FeWO4 were also investigated, and the results showed that a certain amount of Cl-, SO42-, NO3-, HCO3- and PO43- exhibited negligible effects on the degradation of SMX. Theoretical calculations corroborate that the distinctive spin-state reconstruction of Fe center in S-doped FeWO4 is advantageous for H2O2 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 FeWO4 in wastewater treatment.
摘要：
黑钨矿(FeWO4),一种典型的多金属氧酸盐,作为多相催化剂的吉祥候选者，由于其高化学稳定性和电子特性。然而,FeWO4中的缺电子表面活性Fe物种不足以通过Fe氧化还原介导的类Fenton催化反应裂解H2O2。在这里，我们将硫原子掺杂到FeWO4催化剂中，以改善FeWO4的电子结构，用于H2O2活化和磺胺甲恶唑（SMX）降解。此外，在S掺杂的FeWO4上进行自旋态重构可以有效地改善Fe在d轨道上的电子结构，从而增强H2O2活化。S掺杂还加速了硫物种转化过程中的电子转移，促进Fe(III)向Fe(II)的循环。因此,与FeWO4相比，掺杂S的FeWO4使类Fenton反应增强了近两个数量级。重要的是,在实际水样中，开发的S掺杂FeWO4在40分钟内对SMX的去除效率约为100％。这强调了其广泛的pH适应性，强大的催化稳定性，和耐浸出性。还研究了水成分对S掺杂FeWO4性能的基体效应,结果表明，一定量的Cl-，SO42-,NO3-,HCO3-和PO43-对SMX的降解作用可忽略不计。理论计算证实，S掺杂的FeWO4中Fe中心的独特自旋态重构有利于H2O2的分解。这一发现为Fenton类反应中S掺杂的催化活性增强提供了新的机理见解，并为扩大FeWO4在废水处理中的应用铺平了道路。
