High entropy materials promise to overcome the instability and the degradation caused by large electrode volume variations during (de-)lithiation, i.e. during (de-)charging of a lithium battery. Nano-level heterogeneity within such materials may, however, affect the overall performance. Here, as proof-of-concept, low (GeTe, Sb2Te3) and medium ((SnSbBi)Te, (SnSbBiGe)Te) entropy tellurides, as well as medium entropy composite tellurides ((SnSbBi)Te-ZnTe), (SnSbBiGe)Te-Cu1.75Te)) have been explored for effects of entropy and heterogeneity on cycling stability and rate capability. The rate capability is shown to depend on nano-level heterogeneity rather than entropy, but the latter to be important for stable cycling; the medium entropy composite (SnSbBiGe)Te-Cu1.75Te renders up to 140 cycles with good capacity retention (87%) and agreeable average coulombic efficiency (98.8 ± 0.4%). Altogether, characterizing and controlling nano-level heterogeneity is crucially needed to improve performance and to optimize entropy-designed alloy electrodes.

Improving the thermal conductivity of zeolite adsorbents is essential for enhancing the efficiency of thermal swing adsorption (TSA) processes in CO2 capture. In this work, zeolite Y was combined with two types of carbon-based thermal conductive enhancers, expanded natural graphite (ENG) and graphene nanosheets (GRA), to form zeolite–carbon composites. Structural analysis confirmed that the incorporation of carbon additives did not damage the zeolite framework, although the addition of non-porous carbon led to a decrease in surface area and micropore volume. Measurements with a transient hot disk method revealed that the incorporation of ENG and GRA could remarkably enhance the thermal conductivity of zeolite Y-carbon composites. A 7-fold increase in thermal conductivity, from 0.107 to 0.762 Wm−1K−1, was achieved by adding 5wt.% of GRA, whereas a comparable improvement with ENG required a much higher loading of about 30 wt.%. Infrared thermography on packed composite powder on a heated plate indicated that the heat transfer through the composites with improved thermal conductivity is significantly faster compared to plain zeolite. CO2 adsorption measurements indicated that both additives reduced the CO2 uptake capacity, but the loss was significantly smaller for the graphene composites (at 5 wt.% addition), which retained most of the micropore volume. Ideal adsorbed solution theory calculations further showed that the zeolite Y-GRA composites maintained reasonably high CO2/N2 selectivity, though lower than pristine zeolite Y. In conclusion, the zeolite–graphene composites present a promising pathway to improve the intrinsic thermal limitations of zeolite sorbents, enabling faster heating and cooling cycles and improved productivity in TSA-based carbon capture systems.

In 2022, 2.2 billion people lacked safely managed drinking water, and estimates predict an increase of 55% of the global water demand by 2050. One target of Agenda 2030 is to accelerate the pace of progress for drinkable water by six times. To meet this target, devices and materials that can be used as membranes or substrates for water/oil separation and water desalination applications have been widely studied. Ceramic porous materials are good candidates for such applications because they are stable, and their porosity can guarantee high permeability. In this study, porous alumina with vertically aligned pores was prepared by using the freeze-casting technique. This preparation method is widely used to obtain highly porous materials; however, the optimization of the porous structure in relation to water applications has not yet been deeply investigated. In this study, samples with different degrees of porosity were obtained, and the effect on water affinity properties was studied. A slurry composed of α-alumina powder, water as solvent (56, 77 w/v%), poly(vinyl alcohol) as binder (10, 15, 25 w/w%), and polyethylene glycol as dispersant (5 w/w%) underwent directional freezing (freezing temperature of −40 °C with freezing rate of −10 °C/min), followed by sublimation and further sintering at 1550 °C for 4 h. A highly porous sample, with 97% open porosity and low thermal conductivity (6.39 ± 0.05 W/m·K) with respect to bulk alumina, was obtained. The high macroporosity also ensures a good water affinity, both for water absorption and water uptake (9 mm s–1), which was investigated using the apparatus utilized for the density measurement, making the sample a good candidate for water-related applications such as water desalination and water–oil separation.

Catalytic CO2 methanation offers a sustainable approach to convert waste CO2 into high-value methane (CH4). However, designing highly efficient and stable catalysts that operate under harsh conditions remains a significant challenge. The interaction between the active metal and the support material (MSI) plays a critical role in determining the activity and stability of the catalyst. Here, we report the tailoring of MSI by regioselective anchoring of Ni and Co around the edges of hierarchical porous zeolite 13X (h13X), leveraging crystal defects modulated by amine and silanol groups. Scanning transmission electron microscopy and electron energy loss spectroscopy analysis confirmed the growth of approximately 3-nm thick nanolayers of Ni and Co around the edges of h13X crystals. The XPS and H2-TPR analysis of the catalysts revealed shifts in binding energies and reduced H2 consumption, corroborating stronger MSI and electronic interaction between Ni and Co. The optimized catalyst (AF-7.5NiCo/h13X) exhibited a maximum CO2 conversion of 74.4% with a CH4 selectivity of 98% at 20 bar and 400°C under a GHSV of 60,000 mL gcat⁻¹ h⁻¹ and an activation energy of 55 kJ mol⁻¹. More importantly, the catalyst demonstrated stability, with consistent CO2 conversion performance over a month, showing no discernible decrease. The enhanced and stable performance of the catalyst is attributed to the stronger MSI and the sub-5-nm thin layers of Ni and Co over h13X.

The processing of composite granules of waste coffee dust and hollow polymer microspheres with sucrose solution as binder with high-shear granulation is demonstrated as a precursor for subsequent conversion to highly porous, hierarchically porous, mechanically stable structured granules for CO2 capture. The optimization of the granulation parameters, such as binder volume, waste coffee dust to hollow polymer microsphere weight ratio, and the agitator & chopper speed of the granulator, produced near-spherical granules of 4–16 mm in diameter. Subsequent pre-carbonization followed by activation using KOH as a chemical activator yielded activated carbon granules (ACGs) in the 3–5 mm size range. The ACGs exhibited hierarchical porosity with a high specific surface area (350–1573 m2 g-1), total pore volume (0.14–0.54 cm3 g-1), and significant microporosity (0.08–0.50 cm3 g-1). These textural properties enabled high CO₂ adsorption capacities of up to 4.3 mmol g-1 and 10 mmol g-1 at 1 bar and 10 bar, respectively, at 20 °C. The ACGs demonstrated a CO₂/N₂ selectivity in the range of 17.7 to 21.2 and a moderate isosteric heat of adsorption (18–43 kJ mol-1), indicating physisorption and efficient regeneration potential. These findings highlight the potential of structured ACGs as a sustainable, high-performance material with ease of processing for practical CO2 capture and gas separation applications, contributing to circular economy goals through waste valorization. This work demonstrates a scalable shaping route from spent coffee waste to mechanically robust, hierarchically porous granules without a separate palletization step, suitable for practical CO2 capture applications and also contributing to circular economy goals through waste valorization.

The reverse water-gas shift (RWGS) reaction offers a sustainable pathway for converting CO2 into CO, thereby facilitating syngas production. A stable and efficient catalyst is essential for ensuring practical applications without the risk of deactivation. In this study, perovskite oxide supports FeMnO3 (FM), ZrCaO3 (ZC), LaFeO3 (LF), and LaCoO3 (LC) were synthesized via the scalable and facile Pechini sol-gel method and impregnated with 5 wt% Ni and 5 wt% Cu to regulate the redox activity, reducibility, and thermal stability. The comprehensive characterization, including ICP-SFMS, XRD, H2-TPR, TGA, N2 Physisorption, XPS, and SEM, were conducted, confirming successful supported metals addition, high perovskite crystallinity, surface NiO/CuO formation, lower reduction temperatures and enhanced thermal stability. Catalytic testing from 200 to 700°C with different CO2:H2 ratios and feed compositions revealed high RWGS performance at 700°C with 15 vol% CO2, and CO2:H2 = 1:4. Under these improved conditions, Ni- and Cu-impregnated LaCoO3 achieved approximately 66% CO2 conversion with 98–100% CO selectivity. The catalysts demonstrated almost stable performance over 70 h with CO2 conversion stabilizing at 59.2% and maintaining a high CO selectivity (97.5%), with Cu contributing to improved stability by mitigating Ni deactivation. The catalyst retained the structural stability which was revealed by post-reaction XRD and SEM showing high crystallinity and minimal morphological changes. The higher performance of the LC catalyst is attributed to preserved Co3 +/Co2+ redox chemistry, and Ni and Cu supported metals effects, resulting in enhanced CO2 activation and electron transfer. This work demonstrates a dual Ni-Cu impregnation approach on LaCoO3 that enhances stability and RWGS performance, establishing it as a durable catalyst for RWGS applications.

Hydrogen is emerging as a sustainable energy source that can reduce fossil fuel reliance and associated environmental impact. However, it poses embrittlement challenges for storage and transport materials that affect the widespread deployment of the hydrogen economy. Surface modification of materials by employing coatings, thermochemical, mechanical treatments, and others modifies surface chemistry, microstructure, stress states, and enhances surface integrity. These surface modification methods form physical or chemical barriers that impede hydrogen permeation and lower hydrogen-induced degradation. Though an unfavorable combination of thermodynamic properties, hydrogen solubility, and hydrogen diffusivity of the modified surfaces promotes hydrogen embrittlement mechanisms. This review focuses on a comprehensive overview of various surface modification techniques applied to base materials to counter their hydrogen embrittlement susceptibility. This work emphasizes the relationship between the surface modification methods and their effects on microstructural and mechanical properties, and their contribution to hydrogen storage and transport solutions. Additionally, limitations, challenges, and research gaps related to these surface modification techniques for materials in hydrogen infrastructure are discussed.

In this work, the hydrogenation behavior of a near-equiatomic Ti-V-Zr-Nb-Mo-Hf-Ta-W refractory high-entropy alloy (R-HEA) exposed to pressurized hydrogen has been thoroughly investigated. Isothermal gas-phase hydrogen absorption experiments have been performed and a maximum uptake of 1.13 wt.% H has been achieved after exposure to a pure H2 atmosphere at 350 °C and 60 bar H2 for 6 h. This hydrogen absorption capacity is rather low compared to previous literature, where capacities as high as 2.7 wt.% have been reported. The presence of two distinct (Hf,Zr)-mixed oxides at the surface of the particles has been deduced from X-ray diffraction analyses and identified as the main reason for the relatively low H uptake and the minimal impact onto the mechanical integrity of the R-HEA after hydrogenation. The results hereby reported suggest that R-HEAs containing strong oxide-forming elements such as Hf, Zr, and Ti undergo surface hydrogenation-regeneration upon intermittent exposure to a hydrogen atmosphere. The cyclic nature of such phenomena should be further investigated, as it could lead to the development of novel, self-regenerating protective materials against hydrogen diffusion and embrittlement to be potentially used as permeation barriers.

Developing efficient and durable oxygen evolution reaction (OER) electrodes for alkaline water electrolysis requires not only catalytically active components but also strong interfacial integration between the catalyst layer and the conductive substrate. Herein, we report a one-step hydrothermal route for constructing a six-metal NiZnCuCoMnFe LDH-based heterostructure directly on copper foam, denoted as M6-LDH/CF. Rather than forming an ideal homogeneous multimetal LDH phase, the synthesis produces an integrated architecture consisting of a six-metal LDH nanosheet framework, segregated Co/Mn-containing oxide or oxyhydroxide surface phases, and a reconstructed Cu/Cu2O/CuO interfacial region derived from the substrate. Structural analyses indicate that differences in hydrolysis, oxidation, and precipitation behavior among the metal species, together with substrate oxidation under hydrothermal conditions, govern this non-ideal growth pathway. The optimized M6-LDH/CF electrode exhibits overpotentials of 181, 392, and 502 mV at 10, 50, and 100 mA cm−2, respectively, and maintains stable operation at 50 mA cm−2 for 100 h. Post-OER XPS further reveals pronounced surface-state evolution, including Cu oxidation, Zn leaching, and the formation of more metal–oxygen–metal coordination environments, indicating that M6-LDH/CF functions as a precatalyst architecture that evolves toward a more oxidized working state during operation. These results suggest that controlled non-ideal in situ growth can be used constructively to fabricate integrated multimetal OER electrodes with favorable activity and operational stability in alkaline media.

Cermets/Cemented carbides belong to the class of materials that reap the properties of both ceramics and metallic phases and are generally fabricated using powder metallurgical techniques. Fabrication through the conventional solidification route is not feasible due to the high melting points of ceramics. The size and shape of cermets produced by powder metallurgical techniques are rather restricted, and the presence of induced defects will depend on the process conditions. To widen the applications of the cermets/cemented carbides and to fabricate intricate parts with added functionalities, novel additive manufacturing techniques (AM) may be employed for the fabrication of cermets. Since the AM process takes place in a layer-by-layer fashion, the fabrication of cermets can lead to the production of parts with intricate and complex shapes without boundaries. Laser powder-bed fusion process and directed energy deposition are two major laser-based techniques that can fabricate cermets/cemented carbides using the solidification route. One advantage of using solidification-based AM technology is that it can produce near-dense and near-net-shaped components without the need for further post-processing. This review highlights recent advancements in the laser-based solidification of cermets and cemented carbide, addressing their microstructural features, resulting properties, and the challenges inherent to these AM processes.