Latest ArticlesChlorine is not only widely used as an important basic chemical, but also shows promising in-situ electrochemical remediation. Unfortunately, its electrochemical production usually relies on expensive noble-metal dimensionally stable anode (DSA). Herein, a high-performance non-noble metal Co3O4/Ti anode was developed by a simple electrodeposition-calcination method, demonstrating a high efficiency in producing active chlorine in a wide pH range (3–11) and at relatively low Cl- concentration close to different real environmental requirements due to its abundant surface area and active sites provided by the interlaced nanosheet structure anode. Compared with commercial DSA, the Co3O4/Ti anode offered significant advantages in terms of Faraday efficiency, electric energy consumption and economic cost, achieving the rate of active chlorine production of 14.97 mg L-1 min-1 in 0.5 mol/L NaCl electrolyte solution (pH 6) with a Faraday efficiency of 96.8% and low energy consumption of 2.49 kWh/kg. Moreover, the robust backbone structure of the anode enabled the Faraday efficiency to be maintained at about 92.2% without deactivation after ten cycles of reaction. In addition, this Co3O4/Ti electrode demonstrated effectiveness in treating organic pollutants and mariculture wastewater and seawater rapid sterilization. This study provides new inspirations for the construction of highly efficient, low-cost, and low energy consumption non-noble metal cobalt-based anode for the in-situ environmental remediation application.
Per- and polyfluoroalkyl substances (PFASs), especially perfluorooctanoic acid (PFOA), pose a significant threat to ecosystems and human health due to their extreme persistence and bioaccumulative properties. Although metal-organic frameworks (MOFs) show potential for adsorption, their efficiency is limited by insufficient active sites and the inability to control the design of adsorption centers, which is a key bottleneck for practical application. In this study, defect engineering was employed to synthesize NH2-UiO-66 derivatives with gradient defect densities (NH2-UiO-66, -LD, -HD), exposing unsaturated Zr sites to enhance PFOA capture. The optimized NH2-UiO-66-HD exhibited ultrafast kinetics, achieving 95% removal within 30 min and a theoretical adsorption capacity of up to 739.31 mg/g, surpassing most MOFs and traditional adsorbents. Mechanistic studies revealed that defect-induced unsaturated Zr sites act as high-affinity anchors, strongly coordinating with the -COO- group of PFOA, while forming a triple interaction mechanism with N–H···F hydrogen bonds and electrostatic interactions (-NH3+), a synergy not previously reported. The material maintained over 90% efficiency through seven cycles, addressing long-standing regenerability challenges in PFAS remediation. This research pioneers a programmable defect-control approach to create hierarchical active sites in MOFs and first demonstrates the synergy of Zr coordination, hydrogen bonding, and electrostatic attraction for ultra-efficient PFAS removal.
The high sensitivity of platinum (Pt)-based catalysts to CO during the hydrogen oxidation reaction (HOR) at the anode is one of the key issues for the long-term stable development of proton exchange membrane fuel cells (PEMFCs). Modulating the electronic structure of Pt is considered an effective approach to enhancing HOR activity and improving CO tolerance. Herein, we utilized the synergistic effect between the transition metal interstitial compounds (TMICs) of VN and Pt to develop a Pt-VN heterojunction-loaded carbon nanofiber catalyst (Pt-VN/NCNF) for CO tolerance in HOR. The introduction of VN causes electronic orbitals rearrangement of Pt, thereby optimizing the adsorption of H on the Pt surface. Meanwhile, the overlap of the d-band of the electron-deficient Pt with the 1π and 5σ bonding orbitals of CO was significantly reduced, which suppresses the strong CO adsorption on Pt surfaces and leave more active sites for H2 adsorption and oxidation. As a result, Pt-VN/NCNF exhibits a mass activity of 1.26 mA/µgPt, 41 times higher than that of commercial Pt/C. Encouragingly, Pt-VN/NCNF maintains 96.7% of its original activity even in the presence of 1000 ppm CO. As anticipated, Pt-VN/NCNF-based PEMFCs demonstrate superior CO tolerance to Pt/C in H2/CO mixtures with CO concentrations ranging from 10 ppm to 1000 ppm.
The electrochemical CO2 reduction (CO2R) holds the potential to manufacture carbon-based chemicals and fuels while advancing toward carbon neutrality. On the path to achieving practical CO2R, a significant challenge lies in the formation of carbonate salts due to the interplay between CO2, local alkalinity and metal cations. The carbonate issue leads to the wastage of CO2 reactant, thus resulting in low carbon utilization efficiency and high costs for carbonate regeneration. Additionally, such salt formation can threaten the operation stability of the CO2R in electrolyzers equipped with gas diffusion electrodes (GDE). These challenges motivate us to conduct the present review, aiming to provide a comprehensive understanding and propose solution strategies for the carbonate problem. We start from the mechanism insights into carbonate formation with specific analysis on the kinetics of carbonate formation, mass transfer process, and the influence of interfacial pH, followed by the exposition of advanced techniques to monitor the carbonate accumulation. Next, the design strategies to solve the carbonate problem including the optimization of electrolyte, electrode, membranes and operation conditions, are presented, with a highlight on acidic CO2 electrolysis system without introducing metal cations into electrolyte systems. We finally end up by offering future opportunities in this evolving field. These timely and inspiring perspectives can guide researchers in addressing carbonate-related issues and advance CO2R toward practical feasibility.
To elucidate the regulatory mechanisms of interlayers on interfacial polymerization (IP) dynamics and thin-film composite (TFC) membrane performance, UiO-66 and its derivatives with tailored properties were synthesized and employed as interlayers to fabricate TFC membranes. The influence of interlayer's charge and porosity on IP reaction was systematically investigated based on the forward osmosis (FO) system. Results showed that the introduction of the UiO-66 interlayer promoted the diffusion of the reactive monomer during the initial stage of the IP reaction, resulting in a wrinkled and thin polyamide (PA) layer. Compared to the pristine TFC membrane, the UiO-66–0% interlayered TFC membrane exhibited 2.7-fold enhanced water permeability (21.67 L m−2 h−1 (LMH)) but reduced salt rejection (3.69 g m−2 h−1 (gMH)). Incorporation of amino-functionalized UiO-66–30% with enhanced positive charge induced a double-layer PA structure, reducing water flux to 15.13 LMH. Engineering hierarchically porous UiO-66 (HP-UiO-66–30%) achieved balanced performance, maintaining high flux (21.04 LMH) while significantly improving rejection (1.39 gMH). This study demonstrates that strategic modulation of nanomaterial functionality and porosity enables precise PA layer engineering for high-performance TFC membranes with simultaneously enhanced permeability and selectivity.
Porous liquids (PLs), as a new class of porous materials with permanent porosity and liquid fluidity, have attracted extensive research interest due to their excellent physical and chemical properties. Herein, we synthesized a chiral porous liquid D-his-ZIF-8-[Bpy][NTf2] based on a metal-organic framework (MOF) and used it as a new stationary phase to investigate its separation performance by high-resolution gas chromatography. The porosity of this porous liquid system was verified through Brunauer-Emmett-Teller (BET) and positron (e+) annihilation lifetime spectroscopy (PALS). The results showed that the D-his-ZIF-8-[Bpy][NTf2] coated capillary column (column A) exhibited excellent separation performance for n-alkanes, n-alcohols, alkylbenzens, isomers, and racemic compounds. Among them, fifteen pairs of enantiomers including alcohols, esters, epoxides, ketones, haloalkanes, and amino acid derivatives were well separated on column A with good reproducibility and stability. The relative standard deviations (RSDs) of the retention time and peak area of two analytes (3-butyne-2-ol and dichlorobenzene) were <1.80% and 0.80%, respectively. By comparing the chiral recognition ability of D-his-ZIF-8-[Bpy][NTf2] coated column A with D-his-ZIF-8 coated column B, the column A has better separation efficiency for chiral compounds than column B. In addition, the chiral recognition ability of column A is complementary to that of commercially available β-DEX 120 column (column C). Compared with the commercial HP-35 column and the previously reported P5A-C10–2NH2 column for the separation of organic mixtures and/or isomers, column A exhibits similar separation performance and has a good separation complementarity to these two columns. Hence, this work opens up a new way for the practical application of porous framework solid materials in gas chromatography.
Geometrical configurations at the nanometer scale are inherently linked to electronic properties, offering exciting opportunity to engineer the latter through precise structural control. The honeycomb structure, a prominent geometry in two-dimensional materials like graphene, has become a versatile platform for advancing energy technologies, quantum computing, and nanoscale sensing. Achieving a perfect honeycomb network at large scale remains challenging but desired, especially when atomic defects and disorder can severely impact materials' properties and performances. Intrinsic topological defects often persist due to the conformational flexibility of the precursor skeletons, which allows precursor monomers to deform despite variations in preparation parameters. To address this challenge, we employ a tripod molecular precursor, pTBPT, combined with ultrahigh vacuum on-surface synthesis. Networks comprising rings of different edges are initially formed after deposition of pTBPT on Cu (111) at room temperature to 420 K. At low coverage (~0.015 monolayer) selenium doping, we achieve the fabrication of ordered honeycomb networks with much improved structural homogeneity. Selenium doping facilitated the formation of ordered two-dimensional metal-organic nanostructure from 360 K to 480 K. The disorder−order transition of molecular networks through selenium doping on Cu (111) is explored through high-resolution scanning tunneling microscopy (STM). A persistent homology method is resorted to quantify the degree of order of our patterns. The regulation of energy diagrams in the absence or presence of the selenium atom is revealed by density functional theory (DFT) calculations. These findings can enrich the on-surface synthesis toolbox of conformationally flexible precursors, for the design of ordered nanoarchitectures, and for future development of engineered honeycomb nanomaterials.
Organophosphorus (OPs) compounds are extensively utilized in pesticides, chemical warfare agents, pharmaceuticals, and industrial applications due to their distinctive chemical properties, including biological activity, persistence, and hydrophobicity. However, their excessive use has led to significant environmental toxicity and pollution concerns, underscoring the urgent need for sustainable methods to monitor OPs pollutants. Traditional detection relies on bulky instruments, whereas organic fluorescent probes present advantages such as high selectivity, sensitivity, and portability. This review summarizes recent advancements in these probes for OPs detection, outlines characterization strategies based on underlying mechanisms, discusses challenges and future directions, and introduces OPs’ features, probe mechanisms, and design guidelines, providing theoretical insights and technical references for the development of novel organic fluorescent probes.
In light of the prevalent issues associated with metal ion dissolution, secondary pollution, and poor stability in traditional metal-based Fenton catalysts, this study innovatively developed a metal-free carbon-based catalyst co-doped with Si-O bonds and graphitic nitrogen using natural diatomite as the precursor. By leveraging the synergistic effects of Si-O bonds and graphitic nitrogen, the electronic structure of the carbon matrix was effectively modulated, establishing an efficient electron transport channel for peroxymonosulfate (PMS) activation. Results showed that the Fenton-like performance of the resulting catalysts was far superior to those of traditional metal catalysts and can be comparable to various single-atom catalysts. Both the radical and 1O2 pathways exhibited a negligible role in the metal-free Si-O/N@DM/PMS systems. In contrast, electron transfer process (ETP) was the predominate oxidation pathway for acetaminophen (PCM) degradation in the Si-O/N@DM/PMS systems. To facilitate engineering applications, we further designed a proton membrane reactor integrated with a four-channel PMS system, which could introduce an enlarged ETP pathway for pollutant degradation; this addresses the key issues of both sulfate pollution and metal leaching in water caused by traditional metal-based Fenton systems.
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