The detection of trace antibiotics in aquatic environments poses a critical global challenge, threatening both ecological safety and public health. Forward osmosis (FO) membrane separation technology has emerged as a highly efficient approach for purification of trace antibiotics, characterized by high treatment efficiency and low energy consumption. However, challenges inherent to the recycling of draw solutions restrict the development of FO technology. Herein, we report the synthesis and application of a novel CO₂-responsive SiO₂@PDEA nanocomposite as a highly recyclable particulate draw solution. This system leverages CO₂/heat-triggered reversible switching between hydrophilicity and hydrophobicity to enable facile recovery. The 6 wt% SiO₂@PDEA solution leads to a significantly enhanced water flux (J_w) to 5.31 LMH (PRO mode), a threefold increase over bare SiO₂. Crucially, the ratio of reverse solute flux (J_s) to J_w was minimized to 0.015 g/L, providing a substantial cost advantage over inorganic salts. The efficiency of this approach enabled a threefold concentration of tetracycline. Furthermore, the solution demonstrated outstanding cyclic stability with a solute recovery rate consistently exceeding 99% via mild thermal stimulation. These findings demonstrate that SiO₂@PDEA is an exceptionally efficient, sustainable, and cost-effective draw solution with substantial potential for the practical remediation of trace antibiotic-containing wastewater.

Photocatalytic oxidative coupling of methane (POCM) is a promising strategy for the production of sustainable C₂₊ hydrocarbons; however, it typically relies on large quantities of noble metals, such as gold, to serve as active sites for methyl coupling. In this study, we demonstrate that ZnO-supported gold nanoclusters with an average diameter of 1.1 nm provide a robust alternative to conventional gold nanoparticles, enabling efficient POCM even at ultralow gold loadings of 0.1 wt%. The optimized photocatalyst affords a C₂–C₄ hydrocarbon production rate of 3.89 mmol/(g h) with 94.8% selectivity under 365 nm irradiation in a batch reactor. Results reveal that the abundant interfaces between highly dispersed gold nanoclusters and ZnO substrates facilitate charge carrier separation and promote a light-induced Mars–van Krevelen reaction pathway. Methyl adsorption causes gold nanoclusters to exhibit a more intense d-σ hybridization state compared to gold nanoparticles, enhancing electron transfer interactions and substantially reducing the transition-state energy barrier for methyl coupling.

Designing high-performance catalysts from earth-abundant elements remains a critical challenge in the alkaline hydrogen evolution reaction (HER). Copper (Cu) is attractive for its low cost and environmental compatibility; however, it intrinsically suffers from sluggish Volmer kinetics and weak hydrogen binding. Although specific low-index Cu facets offer well-defined atomic arrangements and facet-specific reactivity, their synthesis and stabilization in electrocatalysts remain challenging. Herein, we report a one-step electrochemical reduction strategy that converts hollow Cu₂O nanocubes (NCs) into porous hollow Cu NCs exposing both Cu(100) and Cu(110) facets. This transformation is driven by electrochemically induced lattice reduction and surface atom rearrangement, which increase the density of low-coordination Cu sites and endow them with complementary reactivity, thereby alleviating kinetic limitations associated with water dissociation in the alkaline HER. Consequently, the porous hollow Cu NCs deliver an overpotential of 80 mV at a current density of 10 mA/cm², achieve a 33.7-fold increase in electrochemically active surface area compared with Cu foam, and exhibit excellent durability in 1 mol/L KOH. Moreover, combined in situ Raman and hydroxide adsorption analyses offer direct evidence linking the co-exposed facets to accelerated initial HER kinetics, particularly water dissociation. This study establishes a one-step electrochemical strategy for the synthesis of low-index active Cu facets and offers a broadly applicable design principle for cost-effective HER catalysts.

Catalytic methane combustion is a critical technology for emission control, with Co₃O₄ standing out as a promising non-noble metal catalyst. However, its low-temperature activity requires considerable enhancement. Herein, a sequential “bulk doping–surface etching” strategy is reported to develop defect-rich catalysts. Nanosheet-like Co₃O₄ (Co₃O₄–S), featuring a large specific surface area and excellent catalytic activity, was selected as the optimal platform and subjected to sequential Ni doping and mild acid etching. The resulting catalyst H–NiCo₂O₄–S exhibited exceptional activity with a T₉₀ (the temperature required for 90% methane conversion) of 316.4 °C, representing a reduction of ~ 78 °C in the T₉₀ value compared with pristine Co₃O₄–S, and hydrothermal stability. Systematic characterizations unveiled the synergistic effect of the sequential modification strategy. Ni doping considerably weakened Co–O bonding and induced the generation of abundant active adsorbed oxygen (O_ads). Acid etching introduced numerous surface oxygen vacancies (O_v) and enriched high-valency Ni³⁺ species. Mechanistic studies suggested that these combined modifications facilitated the participation of lattice oxygen, accompanied by a shift in the surface reaction pathway. The accumulation of stable carbonate species was suppressed, and an efficient conversion pathway mediated by highly active intermediates, such as formaldehyde, was promoted. Concurrently, the additional oxygen vacancies and active Co²⁺/Ni³⁺ redox coupling resulting from acid etching considerably accelerated the conversion kinetics of key intermediates. This work demonstrates that co-engineering the bulk-phase reaction pathway and surface active sites is a promising strategy for rationally designing high-performance catalysts.

Direct and selective upgrading of methane to multicarbon hydrocarbons under mild conditions remains one of the most compelling yet elusive goals spanning chemistry, energy, and environmental science. Solar-driven photocatalysis now offers an avenue to activate the inert C–H bonds of methane at ambient temperature and pressure; however, a clear, comparative mechanistic understanding of oxidative coupling versus non-oxidative coupling remains lacking, hindering rational catalyst design and pathway optimization. This review systematically dissects the photocatalytic reaction mechanisms of oxidative versus non-oxidative coupling, outlines key challenges associated with catalyst efficiency, selectivity, and stability, and highlights promising research directions for both pathways. The primary objective of this review is to further advance photocatalytic methane conversion technologies and to provide strategic guidance for the rational design of high-performance photocatalysts.