Atomically dispersed catalysts based on 3d metals have been extensively explored in the catalytic field, but stabilizing 4d and 5d metals like Ru, Pd, and Pt as single atoms remains a challenge due to their high cohesive energies. Herein, we develop a hydrogen-embrittlement-inspired strategy that leverages H2 permeation to weaken metal-metal cohesion in 4d/5d metal clusters during high-temperature synthesis. Hydrogen diffuses into the clusters, driving their dissociation into individual atoms, which are subsequently stabilized by nitrogen dopants in carbon supports, resulting in the formation of stable M-N4 single-atom sites. Taking Ru as a model system, ex-situ microscopy and spectroscopy offer definitive evidence that hydrogen permeation disrupts Ru-Ru bonding interactions, facilitating the conversion of Ru clusters into isolated RuN4 sites during the H2-assisted thermal activation process. Consequently, the prepared NC-Ru-950 catalyst achieves satisfactory activity and stability for acidic oxygen reduction and proton exchange membrane fuel cells. This work introduces a robust and universal strategy for stabilizing 4d and 5d transition metals as single-atom catalysts, offering a promising route to develop high-performance electrocatalysts.

Proton exchange membrane fuel cells (PEMFCs) are increasingly shifting toward low-humidity operation to simplify systems and improve efficiency, necessitating advanced electrocatalyst designs. Herein, we present a mesopore-confined platinum (Pt) catalyst with a high Pt site density that effectively addresses key challenges under dry conditions. The abundant mesopores enhance water retention via capillary condensation, while the high Pt density shortens the nearest-neighbor distance, maintaining continuous proton pathways under low humidity. Additionally, mesopore confinement suppresses Ostwald ripening, significantly enhancing durability. In single-cell tests under H2/air (0.5/2 L min-1, 150 kPa back pressure), the mesoporous carbon-based MEA (m-MEA) achieved 0.719 V at 2000 mA cm-2, exceeding the porous carbon-based MEA (p-MEA) by 58 mV. In a liquid-cooled stack (H2/air, stoichiometry 1.8/2, 50% relative humidity (RH), 150 kPa back pressure), it reached 0.700 V at 2000 mA cm-2, with a 64 mV improvement. Under fan-forced air and ambient pressure, the m-MEA maintained 0.732 V at 500 mA cm-2, surpassing the p-MEA by 81 mV. After 30,000 accelerated stress test (AST) cycles, the m-MEA showed only 26 mV decay at 800 mA cm-2, 61.7% lower than the p-MEA's 68 mV decay, meeting DOE 2025 target of 30 mV.

Metal-nitrogen-carbon (M-N-C) catalysts with atomically dispersed metal sites have emerged as attractive non-precious alternatives to Pt/C for the oxygen reduction reaction (ORR). Among them, Co-N-C systems have received particular attention because of their favorable stability and low cost, yet isolated Co sites often exhibit insufficient O2 adsorption and charge polarization, limiting further activity enhancement. In this study, we introduce Mn into a Co-N-C matrix via a confined adsorption approach to create adjacent Co-Mn sites. The presence of adjacent Mn electronically modulates the Co center, resulting in a CoMnNC catalyst with markedly improved ORR performance. The catalyst delivers half-wave potential (E1/2) values of 0.80 V in 0.1 M HClO4 and 0.919 V in 0.1 M KOH. Under Zn-air battery testing, its maximum power density reached 193.5 mW cm-2, outperforming Pt/C under identical conditions. Density functional theory (DFT) calculations indicate Mn proximity enriches the electron density at Co and downshifts the Co d-band center. This electronic modulation enhances O2 adsorption and charge polarization, weakens the adsorbed O─O bond and lowers the barrier for OOH* formation. This work clarifies how neighboring metal sites regulate the electronic structure of Co centers to facilitate O2 activation and offers a reference for designing excellent M-N-C catalysts.

Humic acid (HA), as a represent of natural organic matter widely existing in water body, dose harm to water quality and human health; however, it was commonly treated as an environmental background substance while not targeted contaminant in advanced oxidation processes (AOPs). Herein, we investigated the removal of HA in the alkali-activated biochar (KBC)/peroxymonosulfate (PMS) system. The modification of the original biochar (BC) resulted in an increased adsorption capacity and catalytic activity due to the introduction of more micropores, mesopores, and oxygen-containing functional groups, particularly carbonyl groups. Mechanistic insights indicated that HA is primarily chemically adsorbed on the KBC surface, while singlet oxygen (1O2) produced by the PMS decomposition served as the major reactive species for the degradation of HA. An underlying synergistic adsorption and oxidation mechanism involving a local high concentration reaction region around the KBC interface was then proposed. This work not only provides a cost-effective solution for the elimination of HA but also advances our understanding of the nonradical oxidation at the biochar interface.

Tailoring the coordination sphere of the metal atoms represents a highly promising strategy to modulate Fe single‐atom catalysts. However, modifications in the first coordination shell often led to reduced catalyst stability, while those in the second shell exhibit limited efficacy in enhancing catalytic activity. In this work, we introduce N‐group elements to engineer N‐X VA dipoles, leveraging their characteristic “high density near the source but sparse at a distance” electric field to modulate the 3d orbitals of Fe. The introduction of N‐X VA dipoles enhances the polarization of Fe single atoms, especially, with the increase of the periods, Fe 3d orbitals rearrangement occurs, resulting in an optimized binding energy for OH* intermediates that approaches the peak of the volcano plot. The resulting FeN4‐Sb/C catalyst exhibits a high half‐wave potential of 0.833 V and a degradation of only 18 mV after 30,000 cycles accelerated durability testing, superior to commercial Pt/C. Furthermore, PEMFCs assembled with the FeN4‐Sb/C catalyst deliver impressive performance (H 2 –O 2 : 1.1 W cm −2 ; H 2 ‐air: 0.6 W cm −2 ), outperforming nearly all recently reported single‐atom and dual‐atom catalysts. This work not only reveals the periodic trend of dipole‐modulated ORR activity in Fe single atom catalysts, but also demonstrates its potential for application in PEMFCs.

In this paper, we report the design of ultrafine ordered PtFeZn ternary intermetallics uniformly supported on ZIF-8-derived Zn,N-codoped graphitic carbon (ZnNC) via a green aqueous impregnation method followed by a two-step annealing protocol (H2/Ar, 600 and 800 degrees C) to circumvent the sintering issues imposed by conventional thermodynamics. Physical characterizations (X-ray diffraction, high-angle annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy) and theoretical calculations reveal that low-temperature annealing at 600 degrees C stabilizes sub-nano disordered PtFe alloys via the strong metal-support interactions (SMSI) between Zn in ZnNC and Pt precursors, while high-temperature treatment at 800 degrees C promotes Zn diffusion from the support into the alloy bulk and simultaneously triggers the disorder-to-order phase transition. The as-prepared ZnNC-15PtFeZn exhibits an initial mass activity of 0.769 mA/mu gPt and retains 61.7% of its activity after 30000 cycles of accelerated stress testing (AST). Notably, when used as a cathode catalyst in MEA, ZnNC-15PtFeZn achieves superior power density (2.018 W/cm2 under H2-O2) at half the Pt loading (0.05 mg/cm2) of state-of-the-art commercial Pt/C, highlighting its potential for low-Pt PEMFCs. Density functional theory confirms that Fe enhances ORR activity via ligand effects, while Zn strengthens Pt-Fe/Zn bonding (elevating vacancy formation energies), thereby improving structural stability. This mild, scalable aqueous impregnation strategy offers a general approach for synthesizing multi-component ordered alloys in electrocatalysis. (c) 2025, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Recently, heterogeneous single-atom catalysts (SACs) have attracted enormous attention in electrochemical applications owing to their advantages of high metal utilization, well-defined active sites, tunable selectivity, and excellent activity. To avoid the aggregation of atomically dispersed metal sites, an appropriate support has to be adopted to reduce the surface free energy of catalysts. Graphene with a high surface area, outstanding conductivity, and unique electronic properties has generally been utilized as the substrate for SACs. Moreover, the correlations between metal–support interactions and the electrocatalytic performance at the atomic scale can be studied on graphene-supported single-atom catalyst (G-SAC) nanoplatforms. In this review, we start from an overview of the synthetic methods for G-SACs. Subsequently, several advanced and effective characterization techniques are discussed. Then, we present a comprehensive summary of recent progress in G-SACs for a variety of electrochemical applications. Finally, we present challenges for and an outlook on the development of G-SACs with outstanding catalytic activity, stability, and selectivity.

Iron‐nitrogen‐carbon materials are being intensively studied as the most promising substitutes for Pt‐based electrocatalysts for the oxygen reduction reaction (ORR). A rational design of the morphology and porous structure can promote the accessibility of the active site and the reactants/products transportation, accelerating the reaction kinetics. Herein, 1D porous iron/nitrogen‐doped carbon nanorods (Fe/N‐CNRs) with a hierarchically micro/mesoporous structure are prepared by pyrolyzing the in situ polymerized pyrrole on the surface of Fe‐MIL‐88B‐derived 1D Fe 2 O 3 nanorods (MIL: Material Institut Lavoisier). The Fe 2 O 3 nanorods not only partially dissolve to generate Fe 3+ for initiating polymerization but serve as templates to form the 1D structure during polymerization. Furthermore, the pyrrole coated Fe 2 O 3 nanorod architecture prevents the porous structure from collapsing and protects Fe from aggregation to yield atomic Fe‐N 4 moieties during carbonization. The obtained Fe/N‐CNRs display exceptional ORR activities ( E 1/2 = 0.90 V) and satisfactory long‐term durabilities, exceeding those for Pt/C. Furthermore, the unprecedented Fe/N‐CNRs catalytic performance is demonstrated with Zn‐air batteries, including a superior maximum power density (181.8 mW cm −2 ), specific capacity (998.67 W h kg −1 ), and long‐term durability over 100 h. The prominent performance stems from the unique 1D structure, hierarchical pore system, high surface area, and homogeneously dispersed single‐atom Fe‐N 4 moieties.

In this study, UiO-66-NH2 fillers were grafted with polyethyleneimine (PEI) and poly(sulfobetaine methacrylate) (pSBMA) and subsequently incorporated into a sythesized 6FDA-ODA matrix to prepare mixed matrix membranes (MMMs). XRD, FTIR, SEM and TGA characterization techniques were used to evaluate the structure and properties of UiO-66-PEI@pSBMA and MMMs. It was found that the introduction of branched PEI and pSBMA can not only avoided the agglomeration of UiO-66-NH2, but also improved the compatibility between the polymer matrix and filler particles. In addition, the UiO-66-PEI@PSBMA was able to bond with a noticeable amount of amino groups and water molecules, and to promote the transportation of CO2 in the membrane. The resulting PI/UiO-66-PEI@pSBMA MMM achived remarkably enhanced gas perm-selectivity compared to pristine 6FDA-ODA membrane and exceeded the Robeson upper bound. The strategy of PEI and polyzwitterion post covalent modification for UiO-66-NH2 provides an effective way to eliminate interface defects and enhance the gas separation of MMMs.

Branched polyethyleneimine (PEI) functionalized UiO-66 were synthesized and used as fillers to fabricated mixed-matrix membranes (MMMs) for CO2/CH4 separation. The purpose of introducing amino-functional groups in the filler is to improve the interfacial compatibility of the filler with the polymer through the formation of hydrogen bonds with the carbonyl group of 6FDA-ODA. Additionally, the amino group can facilitate CO2 transport through a reversible reaction, enhancing the CO2/CH4 separation properties of MMM. The chemical structure and morphology of fillers and membranes were characterized by employing X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), thermogravimetric (TGA), Derivative thermogravimetry (DTG) and scanning electron microscope (SEM). Furthermore, the effects of filler loading and feed pressure on CO2 permeability and CO2/CH4 selectivity have been investigated. MMMs present higher gas separation performance than pure 6FDA-ODA due to the presence of amino groups and the improvement of interface morphology. In particular, the MMM with 15 wt% loading of UiO-66-PEI shows optimum CO2 permeability of 28.23 Barrer and CO2/CH4 selectivity of 56.49. Therefore, post-synthetic modification of UiO-66 particle with PEI is a promising alternative to improved membrane performance.

为提高支撑液膜萃取体系的稳定性,以苯乙烯为接枝单体、二苯甲酮(BP)为光引发剂,通过紫外接枝的方法对支撑体聚偏氟乙烯(PVDF)膜进行疏水改性,研究了制备改性膜的优化实验条件,对改性前后的PVDF膜的官能团、微观形貌和接触角进行了表征,并考察了原膜与改性膜构建的支撑液膜萃取体系处理含酚废水的能力.结果 表明,制备改性膜的优化条件为:紫外光照时间15 min,反应温度30℃,接枝单体苯乙烯的质量分数4％,引发剂BP浓度0.3 mol/L.改性后的PVDF膜的接触角提高了76％,疏水性能显著提高.连续运行5次后,处理含酚废水改性膜除酚率比改性前提高了47％,体系运行更稳定.

Non-noble metal materials are regarded as the most promising catalysts for the oxygen reduction reaction (ORR) to overcome the inherent defects of Pt-based catalysts, like high cost, limited availability and insufficient stability. Here, we fabricate sandwich-like Co encapsulated nitrogen doped carbon polyhedron/graphene (s-Co@NCP/rGO) via a facile and scalable strategy by loading Co-based zeolitic imidazolate framework (ZIF-67) and graphene oxide (GO) layers individually on a polyurethane (PU) sponge template. The 3D sandwich structure is maintained with the assistance of the sponge template, which promotes the uniform dispersion of ZIF-67-derived Co embedded nitrogen doped carbon polyhedra (Co@NCP) and prevents the graphene plates from agglomerating during the annealing process. The final product demonstrates considerable catalytic performance for the ORR with a half-wave potential of 0.85 V, preferable stability and increased poisoning tolerance by comparison to 20 wt% Pt/C, which stems from the 3D sandwich-like structure, N/Co-doping effect, large accessible surface area and hierarchical porous structures. The excellent ORR performance of the catalysts means that they can be utilised in a Zn-air battery as cathode catalysts. During such a demonstration, s-Co@NCP/rGO shows a high open-circuit voltage of 1.466 V, remarkable long-term durability and an outstanding peak power density of 186 mV cm(-2), which shows its high potential as a prospective alternative for widespread practical application in the field of non-noble metal ORR catalysts.

Nowadays, Zn-air batteries have been widely applied in miniature electronic devices and power stations. However, it is imperative but challenging to synthesize efficient non-precious metal electrocatalysts for popularizing application of Zn-air batteries. Herein, the three-dimensional porous Co@Co-NPC is prepared by doping P into flower-like Co/Zn-MOF-derived Co-N-C during the carbonization process. The obtained 3D-Co@Co-NPC possesses an excellent catalytic activity, showing a half-wave potential of 0.872 V for ORR and potential of 1.692 V at 10 mA cm−2 for OER. When employed as air-cathode catalyst in Zn-air battery, 3D-Co@Co-NPC shows a high power density of 182.5 mW cm−2 and a high capacity of 764 mAh g−1. Besides, it displays an excellent charging-discharging cycle stability (over 90 h). The outstanding ORR/OER performance of 3D-Co@Co-NPC are mainly attributed to the doping of P element, which can tune the electronic structure of Co-N-C matrix. The pickling experiment proves that Co nanoparticle can make contribution to ORR/OER activity.

为了提高陶瓷膜的疏水性,本研究选择硅烷分子对氧化铝支撑氧化锆(ASZ)陶瓷膜进行接枝改性.考察接枝硅烷分子结构(反应基团类型)、碳链长度、硅烷分子中含氟和十七氟癸基三乙氧基硅烷(F17C8OEt3)浓度对疏水性的影响.利用SEM-EDS、FTIR、TGA和接触角测量仪对接枝改性ASZ膜或金属氧化物进行表征.研究结果表明,硅烷分子接枝ASZ膜的疏水性能显著提高,接触角从29°增加到136°.FT-IR、TGA结果证明了硅烷分子成功接枝在ASZ膜或金属氧化物上.利用F17C8OEt3硅烷分子接枝改性ASZ管式膜构建渗透蒸发系统处理水溶液中苯酚,实验结果表明,当进料液中苯酚浓度从672.3 mg/L增加至3 844.6 mg/L时,去除的苯酚浓度从29.1 mg/L增加到407.4mg/L;进料液的温度升高到80℃,去除的苯酚是进料液温度为40℃时的5倍.

Rational design and construction of highly efficient and durable non-noble-metal bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial to promote the widespread implementation of rechargeable Zn-air batteries. Herein, a bifunctional catalyst comprising Co nanoparticles uniformly embedded in hollow nitrogen doped carbon tubes (Co@hNCTs) is fabricated by a facile tube-directed templating strategy. In this strategy, surfactant-treated polypyrrole (PPy) nanotubes serve as the structure-guiding templates for efficient capture of Co2+, realizing the in-situ growth of zeolitic imidazolate frameworks-67 (ZIF-67) nanocrystals on PPy nanotubes. Sodium laurylsulfonate acts as anionic surfactant to endow PPy nanotubes with functional electronegative surface and strong anchoring effect toward ZIF-67, playing the pivotal role in binding of ZIF-67 nanocrystals with PPy nanotubes potently. Consequently, the developed catalyst presents a superior ORR activity with the half-wave potential of 0.87 V excellent durability with only a 7 mV loss of half-wave potential after 5000 cycles. The catalyst also exhibits superior catalytic performance for OER. When serving as an air electrode in Zn-air batteries, a large power density of 149 mW cm(-2) and long-term cyclability for over 500 h are realized in ambient air, implying the great potential in practical application.

Beyond reasonable designing catalysts, the optimization of preparing air cathode has far-reaching implications for the development of Zinc-air batteries. In this study, the effect of Polytetrafluoroethylene (PTFE) in current collecting layer on the performance of Zinc-air battery was investigated. The results showed that as the polytetrafluoroethylene (PTFE) content and heat treatment temperature changed, the hydrophobicity and porosity of current collecting layer also changed, thereby affecting the performance of air cathode. The air cathode assembled with PTFE-3-300 possessed an excellent electrochemical performance, which was prepared by brushing PTFE and acetylene black (wherein the mass ratio of them is 18:5) on current collecting layer and then heating at 300 °C. The obtained air cathode displayed relatively small polarization loss and excellent rate performance, showing a polarization potential of - 0.405 V vs. Hg/HgO at 100 mA cm−2 and the voltage retention of 94.47% from 5 to 20 mA cm−2. Besides, the air cathode displayed excellent discharge stability maintaining average potential 1.3249 V for 100 h. Based on this work, a detailed understanding of the relationship of PTFE and current collecting layer can be achieved to improve the electrode design, architecture and fabrication.

Development of high-efficiency non-noble metal materials to substitute Pt-based catalysts for oxygen reduction reactions is crucial in the commercial viability of Zn-air batteries technology. Nitrogen doped carbons (NDCs) are highly appealing as promising candidates. This study reports a facile molten salt (MS) method to synthesize aerogel-like nitrogen doped carbon (NDC-MS). The eutectic mixture acting as combined solvent and porogen leads to the obtained porous materials with extremely large surface area (1548.6 m(2) g(-1)) and relatively high pore volume. The unique aerogel-like structure with hierarchical structure, increased catalytic active sits, extended surface area and large pore volume is beneficial for enhancing oxygen reduction reaction (ORR) performance. The resultant NDC-MS displays a superb ORR catalytic activity with high half-wave potential of 0.88 V, which is one of the most effective figures in previous literature of metal-free catalysts. The superb ORR performance can also be evaluated by Zn-air batteries with satisfactory power density and long-term operation stability. Therefore, such an efficient and green synthetic strategy can open up a new avenue for a wide range of commercial application of heteroatom doped carbon materials in advanced energy technologies. (C) 2020 Elsevier Ltd. All rights reserved.

A new kind of thin film composite membrane (TFC) was prepared through a simple layer-by-layer assembly method. Vinyltrimethoxysilane (VTMS), a kind of silane coupling agent, was grafted on PVDF membrane surface through free radical polymerization method firstly. Then, mesoporous silica nanoparticles (MSN) were uniformly grafted on surface of VTMS/PVDF membrane through reacting with the methoxide group (Si-OCH3) of VTMS. Under the optimized grafting conditions, the MSN grafted density can reach up to 8.73 mg/dm(2). Eventually, the MSN were embedded into polyamide rejection layer through an interfacial polymerization process. The prepared MSN-TFC membrane has excellent permeability and desalination properties. Furthermore, this research provides a new pathway to incorporate MSN into polyamide rejection layer.

This study demonstrated a new method for simultaneously improving the interfacial morphology and gas separation properties of mixed matrix membrane by designing a new type of nanocomposite filler (UiO-66-PEI@[bmim]Tf2N]). Nano-sized UiO-66 particle was post-synthetically modified with branched polyethyleneimine (PEI) and then was decorated with ionic liquid. The abundant amino groups in UiO-66-PEI improve the gas separation properties of the MMM due to the affinity between PEI and CO2. The ionic liquid acts as a lubricant agent, which is coated on the crystal surface improves the interface morphology of the MMM. Compared to pristine 6FO and MOF/6FO membrane, MOF@IL/6FO membrane has higher gas separation performance. Characterization and gas separation results indicated the UiO-66-PEI@ILs particles were homogeneous dispersed in 6FDA-ODA and promoted CO2 transport by reversible reaction with amine groups. Consequently, the membrane sample containing 15 wt% loading of the UiO-66-PEI@[bmini][Tf2N] filler displayed an optimum CO2/CH4 selectivity of 59.99 for CO2 and CH4 mixture gas.

Asymmetric alumina supported zirconia (ASZ) grafted 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFTS) membranes were successfully prepared. The structure, micromorphology, surface elements, roughness and hydrophobicity of the ASZ membrane before and after grafting were evaluated by XRD, SEM, EDS, AFM and contact angle, respectively. The effects of PFTS concentration, different solvents and alkali pretreatment on the hydrophobicity of the membrane surface were investigated systematically. The surface roughness and contact angle increased while the SFE decreased as the pH of the alkali pretreatment increased. The results show that the hydrophobicity of the PFTS grafted membrane depends on the roughness of the modified membrane surface and the low surface energy of the CF2 and CF3 bonds in the PFTS molecule on the membrane surface. The grafting mechanism of ASZ membrane with PFTS was studied by various analytical methods such as XPS, FTIR and TG-DSC, and the grafting process was verified. According to obtained results, PFTS chains were grafted onto the ASZ surface successfully. The PFTS grafted ASZ ceramic membrane is suitable for pervaporation to remove phenol from aqueous solutions, the phenol removal increased from 29.1 mg/L to 138.73 mg/L as the pH of the pretreatment increased from 7 to 11.