Wenwen Chen

The synergistic interaction between radical and non-radical routes in peroxydisulfate (PDS) activation over Mo-Fe bimetallic oxide remains mechanistically unclarified. Herein, a novel Fe-doped MoO2 bimetallic oxide was rationally designed and successfully synthesized via a facile one-pot solvothermal strategy. Mo0.85Fe0.15O2/PDS system achieved ~ 98% levofloxacin (LVX) removal within 20 min, which was attributed to the accelerated dual redox cycles of Fe3+/Fe2+ and Mo6+/Mo5+/Mo4+. Based on radical quenching tests, electron paramagnetic resonance, and electrochemical analyses, radical pathways (sulfate radicals (SO4•−), hydroxyl radicals (·OH), and superoxide radical (·O2−)) and the non-radical pathway (1O2) worked synergistically for LVX degradation. The theoretical calculations revealed that iron doping played a vital role in enhancing interfacial electron transfer toward adsorbed PDS molecules, which facilitates the activation of the O–O bond. High-performance liquid chromatography-mass spectrometry (HPLC-MS) coupled with ecological structure–activity relationships (ECOSAR) revealed stepwise detoxification along the degradation pathways, and bean sprout assays confirmed the low toxicity of resultant intermediates. The proposed metal doping strategy enables the fabrication of high-performance Mo-based catalysts for PDS activation and sheds light on the further development of persulfate-driven remediation technologies.

Selectivity is one of the central challenges in organic photocatalysis, yet how the availability of photogenerated carriers at heterointerfaces regulates competing redox pathways is still insufficiently understood. In this work, an S-scheme heterojunction photocatalyst CdS/CeO2 was designed and prepared, and its performance and mechanism were systematically investigated in the photocatalytic reduction of nitrobenzene, oxidative coupling of benzylamine, and selective oxidation of benzyl alcohol. The heterojunction markedly enhances photocatalytic activity, exhibiting 24-, 12-, and 3.4-fold higher activities than pristine CeO2 for the three reactions, respectively. Radical trapping and in situ infrared spectroscopy reveal that the availability of photogenerated electrons is the key factor governing reduction selectivity. In oxidation reactions, suppression of photogenerated holes markedly affects product selectivity, whereas electrons and superoxide radicals mainly contribute to the overall reaction rate through auxiliary oxygen-reduction pathways. Band-structure analysis, work-function calculations, in situ irradiation X-ray photoelectron spectroscopy (ISI-XPS), and electron paramagnetic resonance (EPR) measurements support an S-scheme charge-transfer mechanism, which preserves strongly reductive electrons on CdS and strongly oxidative holes on CeO2. These results establish a direct relationship between interfacial photogenerated-carrier availability and redox-pathway selectivity in CdS/CeO2, providing mechanistic insight into selective photocatalytic redox transformations.

Utilizing inexhaustible seawater for the photocatalytic H₂O₂ production presents a significant challenge but offers a promising path toward sustainable energy. Herein, a Z-scheme MoO₂-hydrothermal carbonaceous carbon (HTC) heterostructure was developed by a facile one-pot hydrothermal strategy for photocatalytic H₂O₂ production from seawater. The one-pot synthesis enables intimate MoO₂/HTC interfacial contact, which creates efficient charge migration pathways and significantly enhances charge separation. The optimal MoO₂/HTC material yielded a remarkable H₂O₂ production rate of 1078 μmol·g^-1·h^-1 in natural seawater (859 μmol·g^-1·h^-1 in ultrapure water). This superior activity arises from efficient charge separation and the robust redox capability of the Z-scheme heterostructure, as well as the favorable effects of certain ions (Mg²⁺, Na⁺, SO₄^2-) in seawater on charge transfer. Ultraviolet photoelectron spectroscopy (UPS) characterization confirmed the formation of an internal electric field, which is induced by the Fermi level difference between the two materials. Moreover, zeta potential analysis and coexistence ion experiments demonstrated that MoO₂ loading on HTC enhanced H₂O₂ photoproduction in seawater, which is attributed to the improved utilization efficiency of ^•O₂^-. Our findings provide crucial mechanistic insights that set the stage for designing next-generation Z-scheme catalysts capable of efficiently producing H₂O₂ directly from seawater.

The selective reduction of nitrobenzene is considered the primary route for synthesizing azoxybenzene, yet this process often suffers from over‑reduction, resulting in low selectivity toward the target product. Achieving efficient N–N coupling of key intermediates thus remains a central challenge for improving selectivity. To address this, we prepared a series of oxygen‑vacancy‑rich CeO₂ nanosphere catalysts by modulating acetic acid concentration and temperature during hydrothermal synthesis. These catalysts exhibit high specific surface areas (up to 184.1 m² g⁻¹) and demonstrate excellent performance in the highly selective reduction of nitrobenzene to azoxybenzene. Mechanistic studies reveal that oxygen vacancies on the CeO₂ surface promote the condensation of nitrosobenzene and phenylhydroxylamine into azoxybenzene via a confinement effect. Moreover, XPS analysis shows that azoxybenzene adsorbs much more weakly on the catalyst surface than nitrobenzene or aniline, favoring its rapid desorption and thereby suppressing further reduction. This work clarifies how oxygen vacancies in confined microenvironments on CeO₂ enhance the N–N coupling pathway, providing important theoretical and experimental guidance for designing highly selective catalytic systems for nitroarene reduction.

Hydrogen energy has attracted much attention as a clean energy source, but its large-scale application faces storage and transportation challenges. Negative hydrogen medium (metal hydrides and borohydrides) materials have become a research hotspot due to their efficient hydrogen storage capacity. Investigating the role of negative hydrogen in the structure of materials can improve our understanding of the various structural properties of hydrogen and provide valuable insights into the design of hydrogen-containing materials with new functionalities. This paper reviews the research progress on negative hydrogen medium in recent years. Specifically, they include magnesium hydride (MgH₂), sodium aluminum hydride (NaAlH₄), lithium borohydride (LiBH₄), ammonia borane (AB, NH₃BH₃), sodium borohydride (NaBH₄), and potassium borohydride (KBH₄). The catalytic performance of different catalysts used for hydrogen storage and release in the negative hydrogen medium in the last three years is summarized, and the structure–performance relationship of different catalysts for negative hydrogen medium is described on the nanoscale and atomic scale. The reasons for monolithic catalyst and light-enhanced hydrogen release performances are also described. The research progress on the regeneration of negative hydrogen materials is summarized from both computational and experimental perspectives. Finally, the main challenges and development prospects of the negative hydrogen medium in the future are put forward. This review contributes to the basic understanding of the design and mechanism studies of negative hydrogen medium catalysts and provides effective design principles for overcoming the problems of low rates of hydrogen storage and release and the difficulty of cyclic regeneration.

Photocatalysis utilizes sunlight as a sustainable energy source, offering an eco-friendly method for chemical synthesis and energy conversion. BiOX photocatalysts have gained significant attention due to their low toxicity, ease of preparation, and excellent photocatalytic performance. In this study, the BiOX nanosheets featuring with rich oxygen vacancies (OVs) were employed in the efficient photocatalytic C-S coupling reaction of aromatic alkynes and sulfonyl hydrazides, without external bases or additives. Compared to BiOCl and BiOBr, BiOI demonstrated superior catalytic activity for these reactions. Control experiments highlighted that the presence of trace amounts of water in the reaction system enhanced the reaction efficiency. OVs played a crucial role by exposing Bi metal atoms, facilitating water adsorption and dissociation, thereby enhancing hydroxyl radical generation and the improving catalytic activity of BiOI. This novel synthesis approach of alkynyl sulfone not only broadens the application potential of semiconductor photocatalysts but also establishes a new green method for the photocatalytic synthesis of aryl acetylene sulfone compounds.

Antibiotics are crucial medications for preventing and treating bacterial infections. However, due to their inherent resistance to degradation, they are also a major component of water pollutants. Semiconductor photocatalysis is considered to be an important green technology for sewage treatment. In this study, BiVO ₄ /CdS Z‐type heterojunction was synthesized and applied in the photocatalytic degradation of tetracycline hydrochloride (TCH). The Z‐type heterojunction not only facilitates the separation of photogenerated charges, but also preserves photogenerated electrons with strong reduction capability and photogenerated holes with high oxidation capability. Following visible light irradiation for 90 min, the efficiency of BiVO ₄ /CdS photocatalytic degradation of TCH reached 93.1%. Moreover, BiVO ₄ /CdS demonstrates notable degradation efficacy toward other quinolone antibiotics. Free radical trapping experiments and EPR test results suggest that superoxide radicals, hydroxyl radicals, photogenerated electrons, and holes serve as the primary active species in the photocatalytic degradation process of tetracycline hydrochloride. This study offers valuable insights into the development of Z‐type heterojunction photocatalysts for the efficient degradation of tetracycline hydrochloride.

An efficient method for the construction of an array of α-ketoamides has been described from readily available O -benzoyl hydroxylamines and diazo compounds as starting materials by the combined use of CuI as a catalyst and H ₂ O as oxygen source.