Jinhui Zhang

Herein, FeMnO_x composite catalysts were synthesized using the agar method, aiming to enhance the catalytic performance for toluene oxidation. Compared to traditional preparation methods, the agar‐gel technique leveraged the unique templating effect of biopolymer gels, which promoted the uniform dispersion and crystallization of the Fe‐O‐Mn structure, leading to the formation of abundant oxygen vacancies and surface defect sites. Results indicated that the catalytic performance of FeMnO_x (T₉₀ = 225°C) was significantly superior to that of single‐metal oxides, attributed to the enhanced Mn³⁺ content, O_ads, and oxygen mobility induced by the Fe‐Mn synergistic effect. Systematic characterization confirmed that the strong interaction between Fe and Mn in FeMnO_x reduced the Mn‐O bond strength and optimized the adsorption and activation capabilities of oxygen species. In situ DRIFTS analysis further revealed the unique reaction pathway of FeMnO_x: benzoic acid could be directly converted to maleic anhydride, circumventing the formation of phenol intermediates, thereby reducing the accumulation of by‐products and accelerating the deep oxidation of toluene to CO₂ and H₂O. This research presented a novel strategy for the green synthesis of efficient Fe‐Mn catalysts and provided an innovative approach to the catalytic degradation of toluene.

CeO ₂ ‐H ₂ SO ₄ (C‐S), CeO ₂ ‐TiO ₂ (C‐T), and CeO ₂ ‐TiO ₂ ‐H ₂ SO ₃ (C‐T‐S) were used for the selective catalytic reduction of NO with NH ₃ (NH ₃ ‐SCR). Nearly 100% NO _x conversion of C‐T‐S was achieved at 250°C–450°C. When the concentration of Ce ₂ (SO ₄ ) ₃ was excessively high, it causes tightly binding with Ce ³⁺ ions in CeO ₂ , prevents some Ce ³⁺ ions from effectively participating in redox reactions, and results in the inferior SCR activity. Consequently, C‐T‐S possessed the superior catalytic performance due to the optimal content of sulfates. Furthermore, the presence of NO ₂ facilitated the rapid SCR reaction on C‐T‐S, thereby further enhancing the catalytic activity. Additionally, the formation of Ce ₂ (SO ₄ ) ₃ on C‐T‐S could increase the number of acid sites, particularly Brönsted acid sites, resulting in the improvement of SCR performance. C‐S, C‐T, and C‐T‐S mainly followed the Langmuir–Hinshelwood (L–H).

UiO‐66 series metal–organic framework materials (MOFs) are typical porous materials assembled by Zr ⁴⁺ with a large mass‐to‐nucleus ratio and terephthalic acid ligands, which form tetrahedral and octahedral cages arranged in a periodic triangular window pattern. Due to the strong interaction between Zr and O, UiO‐66 series MOFs exhibit high thermal stability, structural stability, and chemical stability. This article mainly reviews the applications of UiO‐66 and its composites in adsorption, photocatalysis, and resource utilization, while exploring the harm of pollutants to human health and the environment. In the first part, the differences in adsorption and removal mechanisms of liquid organic pollutants, heavy metals, and volatile organic compounds (VOCs) are investigated. The results show that organic pollutants are mainly removed by physical adsorption, electrostatic interactions, hydrogen bonding, and π‐π interactions, while heavy metals are mainly removed by chemical adsorption, electrostatic interactions, reduction, and chelation. VOCs are mainly removed by the pore volume and pore size structure of the material. Heterojunction catalysis can achieve non‐toxic treatment of pollutants, and this study mainly focuses on UiO‐based composite materials constructed by strategies such as semiconductor composites, ion doping, and metal/dye encapsulation. In the second part, the synergistic effect between the components of UiO‐based composite materials promotes the oriented and rapid separation and transfer of carriers at the material interface, thereby promoting the generation of active species such as h ⁺ , ·O ₂ ⁻ and ·OH, and achieving rapid degradation of pollutants and detoxification of heavy metals. In the third part, heterojunctions can realize the resource utilization of pollutants in water and air, producing energy‐type substances such as hydrogen and methanol while solving environmental problems. In addition, this article also summarizes the harm of common typical pollutants to the environment and human health. Finally, the development prospects and unresolved problems of UiO‐66‐based materials in water remediation, gas purification, and environmental resource utilization are reviewed.

MnO_x samples were prepared and applied to the catalytic combustion of toluene. The results indicated that the KMnO₄ content was important to the catalytic performance. Cat‐0.2 (0.2 g KMnO₄) possessed the best catalytic performance, and more than 90% of toluene conversion was 255°C. Moderate amounts of KMnO₄ facilitated the generation of mixed crystalline phases and structural defects, which led to the generation of more oxygen vacancies. In addition, the Cat‐0.2 possessed high contents of O_ads/(O_ads + O_latt) and Mn³⁺/(Mn³⁺ + Mn⁴⁺), which promoted the emergence‐annihilation cycle of oxygen vacancies and facilitated the reaction process of toluene. The reaction pathway of toluene was investigated via in situ DRIFTS, in which the by‐products included benzyl alcohol, benzaldehyde, benzoate, maleic anhydride, and short‐chain carbonate. Among them, benzoate was the main intermediate in the catalytic oxidation process of toluene.

Three kinds of three‐dimensional (3D) Mn₂O₃ catalysts with different morphologies (cube, fan‐like structure, and sphere) and various exposed crystal planes were prepared by a hydrothermal method for benzene oxidation. The activity results suggested that sample Mn₂O₃‐Cl with hierarchical cube morphology exhibited a better rate of benzene degradation than the other samples. Mn₂O₃‐Cl exhibited the lowest complete benzene conversion temperature (T₉₀ = 252°C), which was ~48°C lower than that of the Mn₂O₃‐S sample. Meanwhile, the R_m and R_s values of Mn₂O₃‐Cl were 2.71 and 3.21 times, respectively, higher than those of Mn₂O₃‐S. TEM results suggested that morphology has a significant effect on crystal planes. The activity–morphology relationship over the Mn₂O₃ samples was investigated by multiple analytical techniques. It can be concluded that the low crystallinity, superior redox ability, abundant low‐valence Mn ions, and O_latt species in the Mn₂O₃‐Cl catalyst were responsible for its superior catalytic activity.

Iron-based catalysts are widely used in water treatment and environmental remediation due to their abundant content in nature and their ability to activate persulfate at room temperature. Here, eggshell biochar-loaded natural iron slag (IO@ESBC) was successfully synthesized to remove tetracycline hydrochloride (TCH) by activated persulfate. The morphology, structure and chemical composition of IO@ESBC were systematically characterized. The IO@ESBC/PS process showed good performance for TCH removal. The decomposition rate constant (k) for IO@ESBC was 0.011 min⁻¹ and the degradation rate was 3690 mmol/g/h in this system. With the increase of PS concentration and IO@ESBC content, the removal rate of TCH both increased. The IO@ESBC/PS process can effectively remove TCH at pH 3–9. There are different effects on TCH removal for the reason that the addition of water matrix species (humic acid, Cl⁻, HCO₃⁻, NO₃⁻ and HPO₄²⁻). The IO@ESBC/PS system for degrading TCH was mainly controlled by both the free radical pathway (SO₄^•−, •OH and O₂^•−) and non-free radical pathway (¹O₂). The loading of ESBC slows down the agglomeration between iron particles, and more active sites are exposed. The removal rate of TCH was still above 75% after five cycles of IO@ESBC. This interesting investigation has provided a green route for synthesis of composite driving from waste resources, expanding its further application for environmental remediations.