The development of sustainable hydrogen production technologies is crucial to address the global energy crisis and reduce carbon emissions. With growing concerns over freshwater scarcity, the combination of green hydrogen production with ammonia oxidation reaction from wastewater, emerges as a highly promising strategy for meeting carbon goals and reusing treated water. Here, we report a green, scalable, room-temperature chemical reduction method for the successful synthesis of self-supported FeNiB, FeNiBP, and FeNiP electrocatalysts on nickel foams. FeNiB@NF exhibited the highest HER activity, achieving -469 mA cm-2 at -0.71 V vs. RHE with an overpotential of -0.26 V vs. RHE at -100 mA cm-2 in alkaline water and -330 mA cm-2 at -0.69 V vs. RHE and with an overpotential of -0.34 V vs. RHE at -100 mA cm-2 in ammonia-rich electrolyte, while FeNiBP@NF delivered superior OER performance of 972 mA cm-2 at 2.3 V vs. RHE and AOR performance of 963 mA cm-2 at 1.97 V vs. RHE. Physicochemical analysis further revealed that the strong reducing power of sodium borohydride was crucial in generating metallic Fe and Ni states, underpinning the outstanding activity of FeNiB@NF in HER. On the other hand, the synergistic effects of boron and phosphorus in FeNiBP@NF likely facilitated OH* and NH3* adsorption, contributing towards its high catalytic activity in OER and AOR, respectively.

Electrocatalytic hydrogenation (ECH) of organics of biomass origin represents a promising strategy to enable integration of renewables and circular economy practices. However, most electrocatalysts investigated for ECH remain largely based on precious metals. Nanostructured materials based on transition metals encapsulated in a nitrogenated carbon matrix (M@C:N) offer a promising alternative. Herein, we report on the synthesis of Mo@C:N and W@C:N composites that display the same metal atomic concentrations and thus allow for a comparative study of the effect of the metal centre identity on the properties of such heterostructured materials and their performance in the ECH of benzaldehyde, a diagnostic organic substrate. A combination of structural characterisation methods indicates that the type of metal impacts carbon porosity and metal surface concentration in the synthesised structures. W displays a higher tendency to yield encapsulated nanoparticles compared to Mo, which is instead present with surface excess but at predominantly high oxidation states. Electrolysis studies at varying potentials demonstrate high product rates of benzaldehyde hydrogenation, with good selectivity for the production of the corresponding alcohol vs. the dimerization side product. Turnover frequency (TOF) estimates under the operational conditions tested suggest that replacing Mo-centres with W-centres in M@C:N architectures improves overall performance. A comparison of performance indicators with those for Pt-group metals suggests that W@C:N could be a competitive material for practical implementations of ECH.

Two-dimensional (2D) transition metal dichalcogenides, exemplified by molybdenum disulfide (MoS2), have shown exceptional potential for data-centered, energy-efficient electronic applications due to their unique electrical, optoelectronic, and mechanical properties. However, challenges such as the controllable synthesis of high-quality, large-area 2D MoS2films and the mitigation of contamination during growth remain significant barriers to their integration into advanced technologies. Here, photoresist S1813 is innovatively utilized as a contamination-free growth promoter, enabling the clean and scalable synthesis of high quality 2D MoS2on SiO2/Si substrate with desirable grain structures via chemical vapor deposition. By optimizing the reactant concentration and S/Mo ratio, enhanced MoS2growth with improved quality is achieved, as evidenced by the increased MoS2flake size and coverage, alongside a strong photoluminescence A exciton peak at 1.84 eV. This approach facilitates the clean and selective growth of high-quality 2D MoS2, establishing a robust pathway for the practical implementation of 2D MoS2in next-generation electronic devices.

Polytetrafluoroethylene (PTFE) parts are normally consolidated under multi-tonne presses and sintered, but the separate roles of load and temperature on crystal development remain under-explored. Here, we molded PTFE powder under compressive loads (1.2, 1.8 and 2.4 kN) followed by sintering (320, 330 and 340 °C). The starting powder and molded films were characterised using X-Ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Small-Angle X-Ray Scattering (SAXS), Dynamic Image Analysis (DIA) and Scanning Electron Microscopy (SEM). Raising the sintering temperature from 320 °C to 340 °C (at 1.8 kN) increased XRD-derived crystallinity from 63.5% to 71.8% and sharpened five hexagonal-phase reflections ((100)-(210)), while the a and c lattice parameters contracted by ∼0.3% and ∼1.1%, respectively, indicating tighter chain packing. SAXS revealed a concomitant 7% reduction in long-period spacing, and FTIR showed intensified CF2 and C-C bands, signifying enhanced chain alignment. In contrast, elevating the load from 1.2 kN to 2.4 kN at 320 °C trimmed bulk porosity from 33% to 25% without a statistically significant crystallinity change (63.0% → 64.8%). SEM cross-sections established that additional load mainly closes residual inter-particle voids rather than promoting crystal growth. Taken together, the data demonstrates that temperature is the primary driver of phase-IV hexagonal ordering, whereas load chiefly controls densification and has only a minor effect on ordering. This work, therefore, establishes a practical, low-pressure processing window 330 to 340 °C under ∼1.8 kN, which yields highly-ordered (≈72% crystalline), low-porosity (≈25%) PTFE films, providing a cost-effective route for manufacturing PTFE films and components.

Direct seawater electrolysis for green hydrogen production offers a sustainable solution to decarbonize the energy sector without depleting freshwater resources. However, designing efficient electrocatalysts for this process remains challenging. Various physicochemical properties, such as chemical composition, surface chemistry, roughness, and intrinsic resistivity, can impact performance, but they are not fully understood. This study explores how the electrocatalytic activity of amorphous NiMn MBenes in alkaline water, saline water, and seawater can be optimized by adjusting the bimetallic ratio during synthesis. The results show that surface chemistry is the dominant factor influencing electrocatalytic activity. The Ni-rich NiMn MBene exhibits the highest electrochemical surface area (ECSA), charge distribution (CdL), and favourable adsorption of active intermediates, leading to the best electrocatalytic performance. Specifically, achieving a hydrogen evolution reaction (HER) overpotential of -0.28/-0.04/-0.03 V at -10 mA cm- 2 and an oxygen evolution reaction (OER) overpotential of 0.36/0.44/0.25 V at 10 mA cm- 2 in alkaline water/alkaline saline water/alkaline natural seawater, respectively. These findings provide valuable insights into the design and surface engineering of bimetallic MBenes for efficient direct seawater electrolysis.

Engineering nickel boride/borate amorphous/amorphous heterostructures using a simple one-pot chemical reduction method.

Neutron imaging was employed to track the uptake of Gd ^3+ ions by the sub 2 nm micropores of charged activated carbon cloth electrodes from an aqueous Gd(NO _3 ) _3 solution. The transmitted neutron intensity evinces the persistent presence of Gd ^3+ in the micropores during the discharge cycle, which is caused by the adsorption of oppositely charged ions. The charge efficiency of the activated carbon cloth system was determined by direct comparison with the imaged Gd ^3+ concentration changes, with which the influence of ion swapping and resistive losses on capacitive deionization cells can be ascertained.

To improve the wear resistance of CoCrFeNi high-entropy alloys (HEAs) for a wider range of industrial applications, the alloying strategy was applied to CoCrFeNi HEA by doping Mo element in various ratios, and CoCrFeNiMox (x = 0, 0.2, 0.5, and 1.0) HEA deposits were fabricated by cold spray. The microstructure evolution, mechanical properties, and tribological properties of cold-sprayed CoCrFeNiMox HEA deposits were systematically investigated. The results showed that Mo0, Mo0.2, and Mo0.5 deposits have a face-centered-cubic (FCC) single structure, while Mo1.0 deposit was composed of FCC matrix and hard brittle phases. The doping of Mo element into CoCrFeNi HEA deposits significantly increased the hardness due to the enhanced solid solution strengthening and precipitation strengthening. As a result, the anti-wear properties of Mo-doped CoCrFeNi HEA deposits were gradually improved with the increase in Mo ratios. To be specific, the Mo1.0 deposit exhibited the lowest specific wear rate of 5.1 x 10-5 mm3/N & sdot;m, which was reduced by 94.9% in comparison to the Mo0 deposit. Overall, the current study proposes a new strategy to manipulate the mechanical properties of coldsprayed HEA deposits by alloying.

Carbon porous materials containing nitrogen functionalities and encapsulated iron-based active sites have been suggested as electrocatalysts for energy conversion, however their applications to the hydrogenation of organic substrates via electrocatalytic hydrogenation (ECH) remain unexplored. Herein, we report on a Fe@C:N material synthesized with an adapted annealing procedure and tested as electrocatalyst for the hydrogenation of benzaldehyde. Using different concentrations of the organic, and electrolysis coupled to gas chromatography experiments, we demonstrate that it is possible to use such architectures for the ECH of unsaturated organics. Potential control experiments show that ECH faradaic efficiencies >70 % are possible in acid electrolytes, while maintaining selectivity for the alcohol over the pinacol dimerization product. Estimates of product formation rates and turnover frequency (TOF) values suggest that these carbon-encapsulated architectures can achieve competitive performance in acid electrolytes relative to both base and precious metal electrodes.

Green hydrogen is considered an attractive energy vector that can easily replace fossil fuel consumption, meeting global energy demands. Therefore, developing easily scalable, efficient and cost-effective electrocatalysts for water electrolysis is imperative for our transition to a more sustainable energy future. To this end, we demonstrate here a simple and scalable one-pot chemical reduction method for the synthesis of amorphous iron nickel boride nanoparticles with a spherical morphology. The iron to nickel ratio was easily adjusted during synthesis, and how it effects electrocatalytic performance was evaluated. The electrocatalyst powder with the highest concentration of metallic iron, or iron bonded to nickel, exhibited enhanced bifunctional OER and HER electrocatalytic activity, outperforming RuO2, the current state-of-the-art electrocatalyst; reaching industrial current densities, with an OER overpotential of 252 mV at 10 mA cm-2 and 349 mV at 100 mA cm-2. In our view, this work delivers an important method for the scalable synthesis of amorphous bimetallic boride nanoparticles with adjustable electronic structure for achieving enhanced water electrolysis at a minimum cost. Making green hydrogen cost effective by scalable iron nickel boride bifunctional electrocatalysts that can easily reach industrial current densities.

In recent years, the potential of porous soft materials in various device technologies has increased in importance due to applications in fields, such as wearable electronics, medicine, and transient devices. However, understanding the 3-dimensional architecture of porous soft materials at the microscale remains a challenge. Herein, we present a method to structurally analyze soft materials using Focused Ion Beam - Scanning Electron Microscopy (FIB-SEM) tomography. Two materials, polymethyl methacrylate (PMMA) membrane and pine wood veneer were chosen as test-cases. FIB-SEM was successfully used to reconstruct the true topography of these materials in 3D. Structural and physical properties were subsequently deduced from the rendered 3D models. The methodology used segmentation, coupled with optimized thresholding, image processing, and reconstruction protocols. The 3D models generated pore size distribution, pore inter-connectivity, tortuosity, thickness, and curvature data. It was shown that FIB-SEM tomography provides both an informative and visual depiction of structure. To evaluate and validate the FIB-SEM reconstructions, porous properties were generated from the physical property analysis techniques, gas adsorption analysis using Brunauer-Emmett-Teller (BET) surface area analysis and mercury intrusion porosimetry (MIP) analysis. In general, the data obtained from the FIB-SEM reconstructions was well-matched with the physical data. RESEARCH HIGHLIGHTS: Porous specimens of both synthetic and biological nature, a poly(methyl methacrylate) membrane and a pine veneer respectively, are reconstructed via FIB-SEM tomography without resin-embedding. Different thresholding and reconstruction methods are explored whereby shadowing artifacts are present with the aid of free open-source software. Reconstruction data is compared to physical data: MIP, gas adsorption isotherms which are analyzed via BET and Barrett-Joyner-Halenda (BJH) analysis to yield a full picture of the materials.

The combination of 0D nanoparticles with 2D nanomaterials has attracted a lot of attention over the last years due to the unique multimodal properties of resulting 0D-2D nanocomposites. In this work, we developed boron nitride nanosheets (BNNS) functionalized with manganese ferrite magnetic nanoparticles (MNPs). The functionalization process involved attachment of MNPs to exfoliated BNNS by refluxing the precursor materials in a polyol medium. Characterization of the produced BNNS-MNP composites was carried out using powder X-ray diffraction, transmission electron microscopy, vibrating sample magnetometry, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The adhesion of MnFe2O4 magnetic nanoparticles onto the BNNS remained unaffected by repeated sonication and heating in a furnace at 400 C-degrees, underscoring the robust nature of the formed bond. FTIR spectra and XPS deconvolution confirmed the presence of strong bonding between BNNS and the MNPs. Membranes were fabricated from the BNNS and the BNNS-MnFe2O4 nanocomposites for evaluating their efficiency in removing the methylene blue dye pollutant. The membranes have been characterized by scanning electron microscopy, Brunauer-Emmett-Teller surface area analysis, and mercury intrusion porosimetry. The effectiveness of dye removal was monitored using ultraviolet-visible spectroscopy. The BNNS-MnFe2O4 nanocomposite membranes exhibited enhanced MB capture compared to membranes made from pure BNNS alone. The recyclability assessment of BNNS-MnFe2O4 demonstrated exceptional performance, retaining 92% efficiency even after eight cycles. These results clearly demonstrate the high potential of these magnetic nanocomposites as reusable materials for water filtration membranes. Furthermore, the introduction of magnetic functionality as part of the membrane brings an exciting opportunity for in situ magnetic heating of the membrane, which shall be explored in future work.

Removal of dye pollutants from wastewater is among the most important emerging needs in environmental science and engineering. The main objective of our work is to develop new magnetic core-shell nanostructures and explore their use for potential removal of pollutants from water using an external magnetic field. Herein, we have prepared magnetic core-shell nanoparticles that demonstrated excellent dye pollutant adsorbent properties. These nanoparticles are composed of a manganese ferrite magnetic core coated with silica, to protect the core and enable further functionalisation, then finally coated with ceria, which is shown to be an effective adsorbent. The magnetic core-shell nanostructures have been synthesized by a modification of solvothermal synthesis. The nanoparticles were fully characterised at each stage of the synthesis by powder X-ray diffraction (pXRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). These particles were found to be effective in removing methylene blue (MB) dye from water, which was validated by UV-visible (UV-vis) spectroscopy. These particles can be quickly removed from solution using a permanent magnet and then can be recycled after being placed in the furnace at 400 °C to burn off any organic residues. The particles were found to retain their ability to adsorb the pollutant after several cycles and TEM images of the particles after several cycles showed no change in the morphology. This research demonstrated the capacity of magnetic core-shell nanostructures to be used for water remediation.

New CuAl–CO 3 LDH/BNOx nanocomposite membranes demonstrate excellent dye retention characteristics and superior flow rates, as well as efficient photocatalysis for applications in membrane anti-fouling.

In this work, equiatomic CoCrFeNi high-entropy alloy (HEA) was fabricated by solid-state cold spray additive manufacturing technology and then post-spray annealed at the temperature range of 500-1000 degrees C for 2 h. By adjusting the annealing temperature, four types of deposits (i.e., as-sprayed, recovered (500 degrees C), partially recrystallized (700 degrees C), and fully recrystallized (1000 degrees C) deposits) were obtained, and their microstructure, compressive and tensile properties were systematically explored. The as-sprayed deposit exhibited high compressive yield strength due to the dislocation strengthening and grain boundary strengthening effects but fractured within the elastic deformation regime in the tensile test. Such significant tension-compression asymmetry can be attributed to the difference in the sensitivity of the deposit to interior defects (i.e., pores and particle boundaries) under tensile and compressive loads. Only recover annealing hardly influenced the microstructure and mechanical properties of the deposits. While recrystallization annealing could trigger enhanced interface diffusion and the resultant metallurgical bonding, as evidenced by the improved deposit density and less visible interparticle interfaces. The partially recrystallized and fully recrystallized deposits exhibited an excellent combination of compressive strength and ductility. While the fully recrystallized deposit exhibited almost equal tensile and compressive yield strength and the best recovery of tensile ductility, indicating the weakened tension-compression asymmetry.

Nanofiltration (NF) is one of the emerging technologies that is very promising for water purification among many other applications. 2D boron nitride (BN) based nanomaterials are excellent building blocks for NF membranes. In our work, BN nanosheets (BNNS) have been functionalized with magnetic nanoparticles (MNPs) to form BNNS-MNP nanocomposites. It was found that the nanocomposites are stable with the MNPs giving very good coverage with both magnetite and cobalt ferrite MNPs and showing good attachment and stability to sonication. These nanocomposites have been tested for removal of methylene blue (MB) dye and MNPs from water. BNNS-magnetite nanocomposites showed higher removal efficiency of the MB from water than the corresponding pure BNNS, while the BNNS-cobalt ferrite removal efficiency was slightly less than the pure BNNS. The BNNS-cobalt ferrite material was regenerated by burning off the MB and recycled to show the recyclability of this material. The BNNS membranes were tested for filtration of 14 ± 4 nm magnetite MNPs and were found to capture 100% of the nanoparticles with no MNPs left in the filtrate. Thus, we have developed magnetic nanocomposite membranes, which have demonstrated great potential for water remediation. We believe that this research opens up promising ways for production of 2D nanocomposite materials with multiple applications.

In recent years, nanotechnology-based approaches have resulted in the development of new alternative sustainable technologies for water purification. Two-dimensional (2D) nanomaterials are an emerging class of materials for nanofiltration membranes. In this work, we report the production, characterisation and testing of a promising nanofiltration membrane made from water-exfoliated boron nitride (BN) 2D nanosheets. The membranes have been tested for water purification and removal of typical water-soluble dyes such as methyl orange, methylene blue and Evans blue, with the water-exfoliated BN membranes achieving retention values close to 100%. In addition, we compared the performance of membranes made from water-exfoliated BN with those produced from BN using sonication-assisted liquid exfoliation in selected organic solvents such as 2-propanol and N-methyl-2-pyrrolidone. It was found that membranes from the water-exfoliated BN showed superior performance. We believe this research opens up a unique opportunity for the development of new high-performance environmentally friendly membranes for nanofiltration and new sustainable separation technologies.

Here, we report the preparation, characterisation and testing of highly promising nanofiltration membranes produced from partially oxidised BN (BNOx) 2D nanosheets.

Tim A. Butcher, ∗ Lucy Prendeville, Aran Rafferty, Pavel Trtik, Pierre Boillat, 4 and J. M. D. Coey School of Physics and CRANN, Trinity College, Dublin 2, Ireland AMBER Centre and School of Chemistry, Trinity College, Dublin 2, Ireland Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen, Switzerland Electrochemistry Laboratory, Paul Scherrer Institut, CH-5232 Villigen, Switzerland (Dated: July 7, 2021)

The electrosorption of Gd3+ ions from an aqueous 70 mM Gd(NO3)3 solution in monolithic carbon aerogel electrodes was recorded by dynamic neutron imaging. The aerogels have a bimodal pore size distribution consisting of macropores and mesopores centered at 115 and 15 nm, respectively. After the uptake of Gd3+ ions by the negatively charged surface of the porous structure, an inhomogeneous magnetic field was applied to the system of discharging electrodes. This led to a convective flow and confinement of Gd(NO3)3 solution in the magnetic field gradient. Thus, a way to desalt and capture paramagnetic ions from an initially homogeneous solution is established.