Latest ArticlesThis study employed the ferrate(Ⅵ)/sulfur(Ⅳ) (Fe(Ⅵ)/S(Ⅳ)) system to degrade aromatic organoarsenic compounds, with a focus on elucidating the role of in situ-formed Fe(Ⅲ) flocs. The introduction of S(Ⅳ) significantly enhanced oxidative degradation efficiency compared to Fe(Ⅵ) alone, achieving 94.8% p-arsanilic acid (p-ASA) degradation within 3 min. The evolution of active species under varying S(Ⅳ) dosages was systematically investigated via radical quenching experiments and probe compound analysis. SO4•−, •OH and Fe(Ⅳ)/Fe(Ⅴ) were identified as the dominant reactive species in the Fe(Ⅵ)/S(Ⅳ) system, with Fe(Ⅳ)/Fe(Ⅴ) serving as the primary driver of p-ASA degradation. Characterization revealed that Fe(Ⅲ) flocs contributed to arsenic (As) adsorption. While S(Ⅳ) addition altered the morphology and structure of Fe(Ⅲ) flocs, these changes exerted negligible effects on As adsorption capacity. A plausible degradation pathway for p-ASA was proposed, supported by density functional theory (DFT) calculations and degradation product analysis. The system demonstrated robust resistance to common interfering ions, while the low toxicity of degradation byproducts highlighted its potential as a sustainable technology for AOCs elimination. This work elucidated structural modifications in Fe(Ⅲ) flocs induced by S(Ⅳ) and underscored the pivotal role of Fe(Ⅳ)/Fe(Ⅴ), positioning the Fe(Ⅵ)/S(Ⅳ) system as a promising strategy for AOCs degradation.
Species at the air-water interface of microdroplets often display distinct acidity compared to the bulk. In this study, we report that pyrrole, imidazole, pyrazole, and 2H-1,2,3-triazole, a group of five-membered, planar, aromatic, nitrogen heterocyclic compounds that are basic in bulk water, exhibit strong acidity on microdroplets. The deprotonated anions of pyrrole, imidazole, and pyrazole can further react with CO2 to generate the corresponding carboxylic acids, but the triazole anion does not react with CO2. Calculation shows that partial solvation and the electric field on the air-water interface of the microdroplets are the main causes for the increased acidity, and the unique solvation structure of the triazole anion at the interface causes the reactive sites to be shielded by interfacial water molecules, thereby hindering reaction with CO2. These results demonstrate that the electric field and solvation structure of ions at the air-water interface play a decisive role in microdroplet chemistry for these compounds. We anticipate that the unique acidity and reactivity on microdroplets provide a new avenue that is rich in opportunities for green chemistry.
The development of a high-performance pH-universal electrocatalyst for hydrogen evolution reaction (HER) is a vital step toward hydrogen economy but remains a major challenge. Herein, the Pd, Cu, and Ni three elements were confined in a nanoparticle via the microemulsion method. Morphology and structural analysis reveal that PdCuNi nanoparticles are nearly spherical in shape with slight aggregation, and are mainly composed of metallic Pd and Cu, as well as Ni oxide. The electrochemical tests show that PdCuNi exhibits favorable HER catalytic activity in acid (ŋ10: 45 mV; Tafel slopes: 33 mV/dec) and neutral (ŋ10: 71 mV; Tafel slopes: 87 mV/dec) media, and alkaline (ŋ10: 66 mV; Tafel slopes: 116 mV/dec) media. The mechanism analysis implies that the synergistic effect of Pd, Cu, and Ni can improve the inherent conductivity of the catalyst and accelerate the charge transfer process. Furthermore, over 30 h long-term stability has been achieved without significant attenuation. This work provides a strategy for developing versatile and robust multimetallic catalysts towards pH-universal HER.
Cocatalysts are pivotal in realizing photocatalytic overall water splitting (POWS) by mitigating carrier recombination and expediting reaction kinetics. Nevertheless, conventional cocatalysts still faces with challenges in balancing high efficiency and low cost. Herein, adjacent CoP and CoOOH, as noble-metal-free dual cocatalysts for hydrogen/oxygen evolution, are introduced onto the surface of Al-doped SrTiO3 (Al: STO), achieving stable and efficient POWS, with a hydrogen and oxygen evolution rate of 4.86 and 2.30 mmol h-1 g-1, respectively, and an apparent quantum yield of 12.7% at 350 ± 10 nm. The superior performance is attributed to the unique adjacent structure of CoP and CoOOH dual cocatalysts. Functioning as critical reactive sites for hydrogen and oxygen evolution, respectively, co-modification of CoP and CoOOH effectively promotes the surface redox reaction. Notably, due to the Schottky junction form between CoP and CoOOH, the uniformly distributed and tightly attached adjacent CoP-CoOOH dual cocatalysts shortened the distance of both charge-carrier migration from bulk to the surface of photocatalyst and proton transfer from oxidation sites to reduction sites, thereby enhancing the charge-separation efficiency and protecting CoP against oxidation during photocatalytic overall water splitting process. This work offers innovative insights for designing efficient, noble-metal-free cocatalysts for POWS.
Iron-based nanoparticles (Fe-NPs) have wide environmental applications in various areas due to their excellent physicochemical properties, and these processes also increase their release into the water environment. However, the existing literature on environmental behavior fate (e.g., sorption and transformation) and potential ecotoxicity of Fe-NPs remains limited, which is vital for understanding the Fe-NPs environmental behavior and application as a multifunctional product. In this review, the green synthesis, characterization, and environmental application of Fe-NPs are summarized. We systematically examined the impacts of Fe-NPs physicochemical properties on its adsorption, transformation (e.g., aggregation dispersion, dissolution, oxidation), and biodegradation behavior in aqueous ecosystems. Moreover, we highlight the potential ecological toxicity of Fe-NPs to aquatic organisms. Upon exposure in water environments, Fe-NPs have potential ecological toxicity on aquatic organisms (e.g., microorganisms, plants, zooplankton, and fish). The common mechanisms of Fe-NPs ecotoxicity (e.g., bioaccumulation, oxidation stress, and DNA damage) at the cellular level are presented and the remaining unclear points on nano-toxic mechanisms (e.g., metabolic disturbance, genotoxicity) are discussed. Given the unresolved issues, the substantial gaps and the environmental risk assessment of Fe-NPs require further attention in the future. This paper will provide useful information for assessing the fate and potential ecological risks associated with Fe-NPs in aquatic environments.
Conjugated microporous polymers (CMPs) are a class of materials characterized by their rigid π-conjugated network, adjustable microporous structures, and high mechanical strength. Due to these exceptional structural features, CMPs have demonstrated outstanding potential and performance in molecular separation, energy storage, sensors, optoelectronic devices, and catalysts. It has garnered significant attention. However, despite the considerable attention and work paid to synthesizing CMP, the challenges associated with processing it in powders are frequently disregarded. Thus, future advancements must focus on developing strategies to obtain CMPs as film form and how they performed when they are integrated in devices such as batteries, LEDs, supercapacitors, sensors, and solar cells. This paper provides a comprehensive and detailed review of the most recent advances in fabrication strategies and their applications for CMP films as well as the challenges.
Calcium hydride (CaH2) is a hydrogen storage material with high hydrogen storage density that is easy to transport and store. However, its hydrogen generation process is intense and liquid water causes uneven reactions in CaH2. These two issues make the reaction of CaH2 hard to control. To resolve the issues, a gel/nonwoven fabric composite material was prepared using nonwoven fabric and poly(vinyl alcohol)/polyacrylamide (PVA/PAM) hydrogel, and applied to a compact hydrogen generator. Water absorption and evaporation tests on composite membranes confirm that the membrane can control the water transport rate by adjusting the gel content, thereby regulating the hydrogen production of CaH2. During the hydrolysis of CaH2, the heat released promotes water evaporation, which absorbs some of this heat and helps maintain both temperature and water balance. When the gel content was 10%, the height of the separator was 1 mm, and the mass of CaH2 was 1.5 g, the hydrogen generator achieved the fastest hydrogen production rate of 58.7 mL/min. Moreover, after expanding the size of the hydrogen generator, it can continuously produce hydrogen for over 260 min at room temperature. Finally, hydrogen was supplied to a proton exchange membrane fuel cell (PEMFC) stack. This research provides a new concept for controllable hydrogen production and portable fuel cells.
Carbohydrates play essential roles in the physiological and pathological functions of cells. However, carbohydrate structures involve numerous levels of isomerism, which has posed significant challenges to advancements in glycomics. The technique for carbohydrate recognition needs to be precise in determining all aspects of the stereodiversity for both fundamental research and practical applications. Via quantum tunneling simulations and model analysis, we show that a carbon nanotube based nanopore as a molecular tweezer to trap a single target analyte with controlled dwell time achieved through reversible flexoelectric gating. Under mechanical deformation, the pore walls act as dynamic electrostatic binding sites to capture analyte enabling ample but fast sampling. After establishing Fano resonance as the sensing mechanism to quantitatively evaluate the interaction between the pore wall and analyte, random forest classifier algorithm is employed to classify the quantum transport data. This sensing strategy provides a general discrimination accuracy of higher than 99.4% for identifying carbohydrate isomers. Our findings highlight the efficacy of this combined physics and machine learning-based method in addressing the stereochemical complexity of carbohydrates. The approach not only improves observation time per molecule but also operates in a high-throughput format, offering a powerful artificial intelligence (AI)-empowered biomolecule sensing tool for glycomics research.
Sustainable photochemical CO2 conversion represents a promising strategy for mitigating excess CO2 emissions and achieving "carbon neutrality". The development of advanced catalysts with an abundance of active sites and efficient separation of photo-generated charge carriers remains a significant challenge. Here, we present a high-entropy (HE) photocatalyst by integrating five metals into Prussian blue (PB) to afford Kx(MnFeCoNiCu)[Fe(CN)6] (HE-PBA) which exhibits a high concentration of active centers and rapid electron transfer, enabling superior CO2-to-CO photoreduction performance. The HE-PBA composite catalyst delivered a high CO yield (up to 1220.5 µmol g-1 h-1), achieving near 100% product selectivity. A mechanistic analysis has revealed strong coupling and overlapping multi-atomic orbitals, which facilitates local electron redistribution and a readjustment of electron density. This effect serves to generate abundant reactive sites with CO2 interactions that facilitate C-O bond activation. Additionally, an efficient electron transfer driven by the disparity in metal electronegativity inhibits unwanted recombination of electron-hole pairs. More significantly, the photoelectrons migrate and accumulate on the HE-PBA surface, exhibiting extended long lifetimes and robust reduction ability. The findings of this study provide important insights that can contribute to the development of high-entropy materials rich in transition metals with far-ranging potential applications.
Extensive research has been devoted to single-atom activation of persulfates in recent years. However, mechanistic understanding of the distinct interactions between different persulfates (i.e., peroxymonosulfate (PMS) and peroxydisulfate (PDS)) and the coordination environments of single-atom catalysts (SACs) remains critical for advancing their practical applications. Herein, we developed a Fe-N4 SAC exhibiting dual activation capabilities for both PMS and PDS. Intriguingly, experimental results revealed divergent activation mechanisms: PMS activation was predominantly mediated via single-site reactions generating singlet oxygen (1O2), whereas PDS activation proceeded through both dual-site and single-site pathways involving concurrent 1O2 generation and electron transfer processes. Density functional theory calculations further demonstrated that the geometric alignment between the inter-site distances of Fe-N4 centers and the molecular dimensions of PDS serves as the key determinant for enabling the electron transfer pathway. This fundamental structure-reactivity correlation suggests that the intrinsic molecular-scale differences between PMS and PDS govern their distinct interaction mechanisms with Fe-N4 SACs. Finally, the scale-up experiments realized nearly complete sulfamethoxazole degradation during 120 h continuous operation without obvious decline in both the Fe-N4/PMS and Fe-N4/PDS systems. This work provides fundamental insights into molecular-scale effects on persulfate activation mechanisms, establishing new design principles for SACs optimization in advanced oxidation processes.
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