Galvanic replacement reaction (GRR), which arises from the difference in redox potential between two metal species in different oxidation states, is a powerful tool for designing structures with unique functionalities. However, extending GRR to more than two metals to target homogeneous structures remains puzzling. Here, we interrogated a single-step, low-temperature, convergent GRR strategy for assessing silver-platinum-palladium materials with tunable physicochemical and electrocatalytic properties. We synthesized carbon-supported silver (Ag/C, 19 wt %) using a solid-state carbo-reduction method. Then, silver atoms within Ag/C were engaged in GRRs with Pt(II)-Pd(II) species within a brine solution. Although thermodynamically favorable, the GRR between Ag(0) and Pt(II) requires a larger molar excess of Pt(II) than that between Ag(0) and Pd(II). We postulate that, in the presence of both metal precursors, the mechanisms of preferential replacement of silver atoms at the center of the particle by Pt(II) and homogeneous replacement by Pd(II) converge to produce porous architectures. Extensive characterization combined with glycerol electrooxidation and the oxygen reduction reaction (ORR) reveals the potential to drastically tune the electrocatalytic properties of the resulting materials by adjusting their electronic properties based on the amounts of Pt and Pd that enter and Ag that leaves the initial structure. This yields a low-loading trimetallic Ag/C_GRR-Pt+Pd electrocatalyst (3-9 wt % Pt+Pd) whose catalytic activity toward glycerol electrooxidation is twice that of bimetallics (Ag/C_GRR-Pt and Ag/C_GRR-Pd) and five to ten times that of state-of-the-art Pt/C and Pd/C electrocatalysts. The present knowledge could stimulate the exploration of complex GRR processes for designing medium- to high-entropy materials.

Electrochemical CO2 conversion offers a direct route to decarbonized fuels, but its deployment on industrial flue gas remains hindered by the low CO2 content, high O2 levels, and the resulting parasitic oxygen reduction. Binary solvent electrolytes offer a lever to tune the local reaction environment under such dilute and impurity-rich conditions. Here we show a direct reactive capture (DRC) strategy that converts CO2 from dilute streams into CO with near-quantitative Faradaic efficiency in organic electrolytes under moderate pressure. We identify hydrogen-bond donation ability (HBD) as a decisive parameter governing competing hydrogen evolution and oxygen reduction reactions. Employing low-HBD electrolytes disrupts the hydrogen-bond network, suppresses competing reactions, and enables selective CO2 conversion even at 1% CO2 in the presence of O2. When fed with 15% CO2 and 8% O2 balanced with N2, the optimized system sustains >100 h operation with an energy consumption of 30.7 GJ ton-1 CO, and achieves a solar-to-fuel efficiency of ~5.5%. This impurity-tolerant strategy addresses a key barrier for industrial CO2 electrolysis and establishes a scalable route to solar-driven fuel production directly from flue gas.

The use of advanced oxidation processes (AOPs) for micropollutant removal in wastewater is challenging, given the scavenging effects of dissolved organic matter (DOM). Chlorine photolysis (UV/Cl) offers unique advantages over conventional AOPs, with wavelength- and pH-dependent generation of reactive species, while being largely compatible with existing disinfection dosing infrastructure. Here, the UV/Cl treatment of carbamazepine (CBZ) was optimized as a test case by varying UV wavelength and solution pH in the presence of humic acid and various types of wastewater DOM isolates (colloidal, hydrophobic, and transphilic). CBZ degradation rates, competitive quenching experiments, and electron paramagnetic resonance spectroscopy revealed important wavelength- and pH-dependent trade-offs in the dominant oxidants. At pH 3, CBZ degradation was hindered by DOM due to scavenging of nonselective radicals. At pH 8, ozone formation minimized DOM interference and improved CBZ removal. Shifting to longer wavelengths caused changes parallel to raising the pH. Three-dimensional excitation-emission matrix fluorescence analysis revealed preferential reactivity with fulvic- and humic-like fluorophores during treatment. Microtoxicity bioassays indicated a slight increase in acute toxicity after UV/Cl exposure, and LC-MS identified hydroxylated, epoxidized, and chlorinated transformation products. Results highlight the potential for strategic optimization of UV/Cl to mitigate DOM interference in water treatment.

Ammonia alane (AlH3NH3, AA) is a solid hydrogen carrier with a high gravimetric hydrogen storage capacity of 12.86 wt%. In this study, we present the first experimental investigation of Al-N-H compounds synthesized via three distinct routes: (i) Lewis acid-base reaction, (ii) metathesis, and (iii) cryo-milling. Characterization techniques including FTIR spectroscopy, thermal analysis, X-ray photoelectron spectroscopy, and solid-state 1H and 27Al MAS NMR spectroscopy revealed the coexistence of multiple aluminum environments. However, the successful formation of AA could not be confirmed. Ambient storage and mild thermal activation (at 80 degrees C) led to the formation of Al-N polymers, likely resulting from dehydrogenation and partial deammoniation, underscoring the thermal instability of these phases. These findings highlight the need for a rigorously controlled synthesis-tocharacterization workflow under inert and subzero conditions (below -45 degrees C) to enable the isolation, comprehensive characterization, and evaluation of pristine AA for solid-state reversible hydrogen storage applications.

Ion-exchange resins (IERs) can effectively remove per- and polyfluorinated alkyl substances (PFAS) from water through electrostatic interactions between the negatively charged PFAS and the positively charged anion-exchange functional groups on the resins. To mimic this behavior while developing anion-exchange adsorbents with high PFAS adsorption capacity, nanostructured block copolymer (BCP) membranes were fabricated with a high areal density of accessible ion-exchange sites by forming N-methylpyridinium-containing alternating gyroid (GA) nanochannels. These GA nanochannels, with physical continuity across the entire anion-exchange membrane (AEM) thickness, allowed for easy and homogeneous penetration of long-chain PFAS molecules (specifically perfluorooctanoic acid (PFOA)) throughout the entire membrane thickness, leading to a high potential adsorption capacity. In contrast, in analogous BCP AEMs with a nominally microporous and disordered sponge-like morphology, PFOA molecules mainly accumulate near the top and bottom surfaces. Our results also show that ion exchange is the primary mechanism of PFAS uptake since a lack of adsorption of PFOA molecules was observed on (neutral) pyridine-containing BCP membranes, regardless of whether they had a GA or sponge-like morphology.

Nanofiltration employing ceramic membranes represents a promising alternative for tertiary and quaternary wastewater treatment due to their superior mechanical and chemical stability over polymeric membrane materials. However, many applications of NF ceramic membranes are still limited by severe organic fouling. The present study investigates the fouling mitigation applied to real urban wastewater secondary effluent in hybrid operation system coupling filtration with catalytic ozonation. Analysis of the effluent organic matter revealed humic-like substances as key contributors to irreversible internal fouling, while protein-like compounds mainly induced reversible cake formation. It has been evidenced that the catalytic ozonation enables a full flux recovery (Flux recovery ratio (FR) ≈ 100%) and may therefore outperform chemical cleaning in reversibility, long-term stability and cost effectiveness. Moreover, the catalytic membranes demonstrated a superior anti-fouling behavior when ozone was continuously applied during the filtration process. An optimal ozone concentration was 25 g.Nm−3 (≈ 0.5 gO₃per g of dissolved organic carbon (DOC)), ensuring efficient removal of foulants, while minimizing ozone consumption. The highest flux stability and organic compounds removal was obtained while achieving chemical oxygen demand (COD) to total organic carbon (TOC) ratios below 2 indicating the formation of more biodegradable by-products. These findings demonstrate that catalytic ozonation coupled with the filtration process significantly enhances membrane sustainability, improving cleaning efficiency, and enabling stable long-term operation in real wastewater treatment.

The persistence of per- and polyfluoroalkyl substances (PFASs) in aquatic environments requires efficient and sustainable treatment technologies. In this study, the electrochemical degradation of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) was investigated using a grid-shaped Ti4O7 Magnéli-phase anode under electro-oxidation (EO) and electro-oxidation coupled with electro-Fenton (EO-EF) conditions. Structural characterization confirmed the predominance of Ti4O7 in the electrode material. At an initial concentration of 2 ppm, PFOS was rapidly and almost completely removed under both EO and EO-EF, whereas PFOA exhibited slower degradation kinetics, identifying it as the kinetically limiting compound. Coupling EO with electro-Fenton mainly enhanced the degradation kinetics, particularly for PFOA, while final removal efficiencies remained comparable. The influence of initial concentration was further examined, showing that lowering the PFOA concentration to 0.2 ppm, representative of environmentally relevant levels, enabled nearly complete removal within 300 min. Fluoride ion monitoring under optimized EO-EF conditions confirmed partial defluorination, demonstrating that PFOA removal is accompanied by C-F bond cleavage. These findings highlight the respective roles of EO and EO-EF processes and support the potential of Ti4O7-based anodes for energy-competitive PFAS remediation.

Moving towards a circular economy, upgrading industrial waste products rich in metals and minerals into valuable materials essential for digital devices, catalysis, and environmental remediation is a key step. The procedures must be eco-friendly, efficient, and yield high production rates. In this work, we propose a microwave-assisted conversion process that transforms iron-rich oxide products (e.g., Fe2O3, Fe3O4) into long iron oxalate crystals with mixed oxidation states using a green solvent mixture of water and CyreneMT - a bioderived solvent. Results show that an equal volume fraction of water and CyreneMT enables uniform crystal growth with an average length of 71.5 +/- 10.5 mu m while achieving high conversion yields. The procedure is timeand energy-efficient, environmentally friendly, and potentially applicable to a wide range of industrial residues, as demonstrated in this work for steel slag.

This study evaluates the efficiency of sub-stoichiometric Ti4O7 titanium oxide anodes for the electrochemical degradation of glyphosate, a persistent herbicide classified as a probable carcinogen by the World Health Organization. After optimizing the process operating parameters (pH and current density), the mineralization efficiency and fate of degradation by-products of the treated solution were determined using a total organic carbon (TOC) analyzer and HPLC/MS, respectively. The results showed that at pH = 3, glyphosate degradation and mineralization are enhanced by the increased generation of hydroxyl radicals (●OH) at the anode surface. A current density of 14 mA cm−2 enables complete glyphosate removal with 77.8% mineralization. Compared with boron-doped diamond (BDD), Ti4O7 shows close performance for treatment of a concentrated glyphosate solution (0.41 mM), obtained after nanofiltration of a synthetic ionic solution (0.1 mM glyphosate), carried out using an NF-270 membrane at a conversion rate (Y) of 80%. At 10 mA cm−2 for 8 h, Ti4O7 achieved 81.3% mineralization with an energy consumption of 6.09 kWh g−1 TOC, compared with 90.5% for BDD at 5.48 kWh g−1 TOC. Despite a slight yield gap, Ti4O7 demonstrates notable efficiency under demanding conditions, suggesting its potential as a cost-effective alternative to BDD for glyphosate electro-oxidation.

This study investigated Rhodamine B (RhB) degradation by electro-Fenton (EF), anodic oxidation (AO), and their combination (EF/AO), using a carbon felt cathode coupled to a sub-stoichiometric titanium dioxide Magnéli phase (Ti4O7) anode or a platinized titanium (Ti/Pt) anode. The results indicated that operational parameters influenced the kinetics of electrochemical reactions. An increase in current density from 10 to 50 mA cm−2 significantly enhanced the RhB degradation rate; 30 mA cm−2 was the optimal current density, balancing both energy efficiency and degradation performance. Moreover, higher RhB concentrations required longer treatment. The Microtox® bioluminescence inhibition test revealed a significant toxicity decrease of the dye solution during electrochemical degradation, which was highest with EF/AO. Similarly, total organic carbon removal was highest with EF/AO (90% at pH 3), suggesting more efficient mineralization of RhB and its by-products than with EF or AO. Energy consumption remained relatively stable with all oxidation processes throughout the 480 min electrolysis period. High-resolution mass spectrometry elucidated RhB degradation pathways, highlighting chain oxidation reactions leading to the formation of intermediates and mineralization to CO2 and H2O. This study underscores the potential of EF, AO, and EF/AO as effective methods for RhB mineralization to develop sustainable and environmentally friendly wastewater treatment strategies.

The formation of (bi)carbonate in alkaline and neutral membrane-electrode assembly (MEA) electrolyzers poses an unsatisfactorily low upper-bound of carbon efficiency. Electrolyzing CO2 in acidic MEA has been regarded as an effective strategy to prevent carbonate formation and CO2 loss but poses challenges due to the competitive hydrogen evolution reaction. Here we report the preparation of a hydrogel buffering layer on an Ag-coated gas diffusion electrode to prevent the (bi)carbonate formation and break the theoretical limitation of 50 % SPU in neutral-media electrolyzers. Through precise control of the porosity within the buffering layer, while maintaining superaerophobicity, we found that the hydrogel enhances the mass transfer of regenerated CO2 at the interface between the buffering layer and the cation-exchange layer. The high energy efficiency of 37 % and carbon utilization of 77 % +/- 2.4 at a total current density of 375 mA cm- 2 were achieved using an optimal Ag/ buffer electrode when performing acidic MEA electrolysis.

Organic solvent nanofiltration (OSN) membranes hold substantial promise for energy-efficient molecular separations in chemical and pharmaceutical industries, yet current technologies often face limitations in solvent permeation and precise sieving. To address these issues, we introduce novel nanolaminated membranes assembled from single-layer, two-dimensional (2D) mesoporous silica nanosheets with inherently uniform in-plane pores. These silica nanosheets, synthesized via a surfactant-templated soft approach, feature highly ordered and tunable hexagonal porosity with sub-10 nm thickness. By adjusting the surfactant carbon chain length, silica nanosheets with controllable pore dimensions were prepared and subsequently stacked into defect-minimized nanolaminate structures. The resulting membranes exhibited polarity-dependent solvent permeation, with permeance values up to 238 L m-2 h-1 bar-1 [LMHB] for polar solvents. Molecular sieving evaluations further revealed robust size-selective performance, achieving molecular weight cut-offs as low as 678 Da with high solvent flux. Remarkably, these nanolaminated silica membranes surpassed existing state-of-the-art OSN membranes in both permeability and selectivity benchmarks. Our findings underscore the potential of precisely engineered 2D mesoporous silica nanosheets as scalable and chemically robust building blocks for next-generation OSN membranes tailored for advanced molecular separation applications.

The direct growth of Metal-Organic-Frameworks (MOFs) on ceramic substrates is a promising strategy to promote their industrial implementation. Yet, the lack of deep scientific comprehension regarding the in-situ conversion of metal derivatives into MOFs, resulting in limited control over their crystal growth, morphology and distribution, hampers their up-scale production. In this work, we provide for the first time the experimental evidence that a competition between MOF formation and alumina facet rearrangement occurs at extended reaction times up to 90 min. We demonstrate that the facet rearrangement induced by pH variations dictates the final morphology and distribution of MOF(Al) crystals grown during the MW-assisted hydrothermal synthesis in water. Hence when facet-rich alumina substrate is used for oxide-to-MOF conversion, short reaction times ought to be applied.

Mechanically improved polymeric membranes with high ionic conductivity (IC) and good permeability are highly desired for next-generation anion exchange membranes (AEMs) in order to reduce Ohmic losses and enhance water management in alkaline membrane fuel cells. To move towards the fabrication of such high-performance membranes, the creation of hydrophilic ion-conducting double gyroid (DG) nanochannels within block copolymer (BCP) AEMs is a promising approach. However, this attractive solution remains difficult to implement due to the complexity of constructing a well-developed ion-conducting DG morphology across the entire membrane thickness. To deal with this issue, water permeable polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) membranes with ion-conducting DG nanochannels were produced by combining a solvent vapor annealing (SVA) treatment with a methylation process. Here, the SVA treatment enabled the manufacture of DG-forming BCP AEMs while the methylation process allowed for the conversion of pyridine sites to N-methylpyridinium (NMP+) cations via a Menshutkin reaction. Following this SVA-methylation method, the IC value of water-permeable (~384 L h−1 m−2 bar−1) DG-structured BCP AEMs in their OH−counter anion form was measured to be of ~2.8 mS.cm−1 at 20 °C while a lower IC value was probed, under the same experimental conditions, from as-cast NMP+-containing analogs with a non-permeable disordered phase (~1.2 mS.cm−1).

As global energy demand continues to rise, hydrogen purification plays a pivotal role in advancing the "hydrogen economy", ensuring the required purity levels for its direct use or storage. This work presents the synthesis and functional characterization of palladium-based hydrogen-selective composite membranes applicable for gas separation below 300 degrees C. These membranes were prepared via Atomic Layer Deposition (ALD) of palladium (Pd) onto asymmetric ceramic tubular supports, using palladium hexafluoroacetylacetonate Pd(hfac)(2) and formalin at 220 degrees C. Prior to Pd deposition, the gamma-Al2O3 top-layer of the support was modified with an ultra-thin (similar to 1 nm) amorphous alumina layer also deposited by ALD. This strategy enhances the number of nucleation sites for Pd, resulting in the formation of thin, uniform and compact membranes. It also substantially reduces Pd precursor consumption compared to conventional methods. The gas separation factors at 286 degrees C were 86 for H-2/N-2, 79 for H-2/CH4 and 67 for H-2/CO2. Additionally, the composite membranes demonstrated resilience to repeated temperature cycling and were able to restore their performance after exposure to trace amounts of CO.

Emerging contaminants have become a global concern in recent years. Ozonation is an effective treatment for their degradation. However, it may generate toxic by-products under certain conditions. Catalytic ozonation is an option for improved contaminant oxidation, which can be enhanced by incorporating a filtering membrane, adding the advantages of retaining molecules, ions, and colloids. Recent studies have demonstrated the catalytic potential of a nanofiltration membrane functionalized with a thin layer of mesoporous maghemite (γ-Fe2O3). However, they have not tested its efficiency in real environmental matrices. In this study, the efficiency of a ceramic membrane functionalized with maghemite was tested for the removal of seven contaminants (carbamazepine, acetaminophen, sulfamethoxazole, caffeine, sodium diclofenac, diuron, and ketoprofen). The performance of ozonation and nanofiltration and the combination of both, with and without the functionalized γ-Fe2O3 layer, were compared for ultrapure water and secondary effluent with contaminants at a concentration of 0.5 mgL−1. The coupling of ozonation and functionalized membrane had around 20

We report a proof-of-concept synthesis of Cu-Ag-Pd nanostructures via concerted galvanic replacement reactions between copper(0) and silver(I)-palladium(II). This methodology enables dramatic enhancement of the electrocatalytic properties of the derived materials by adjusting the lattice strain depending on the amounts of incoming Pd and Ag, and outgoing Cu from the template.

Nanostructured hybrid anion exchange membranes (AEMs) with enhanced mechanical properties were fabricated by first applying a solvent vapor annealing (SVA) treatment to a block copolymer (BCP) film, enabling the formation of a double gyroid (DG) morphology, followed by the chemical vapor infiltration (CVI) of an inorganic precursor to create robust ion-conducting DG nanochannels. To optimize the ion conductivity (IC) while preserving the mechanical strength, solvent-annealed (24 h, dichloromethane) BCP films were infiltrated with a 3-iodopropyltrimethoxysilane (IPTMS) vapor for various durations. The bifunctionality of IPTMS introduces a trade-off between the IC and mechanical properties, as the CVI process simultaneously enhances ion conduction by releasing free iodide through its reaction with the BCP chains and reinforces mechanical stability via the formation of non-conductive silica-rich domains within the DG nanochannels. The resulting hybrid AEMs, with a storage modulus (EIS' approximate to 400 MPa at 25 degrees C) that is 10 times higher than that of their neat counterparts (E ' approximate to 15 MPa at 25 degrees C), exhibit an IC as high as 3.2 x 10-5 S.cm-1 at 30 degrees C.