ABSTRACT This work explores an innovative approach to convert CO 2 into a valuable energy resource using ionic liquid (IL)–based electrochemical systems. The employed ionic liquid, [DBUH][Im], combines the strong CO 2 affinity of imidazole with the high basicity of DBU, promoting selective carbamate formation while suppressing parasitic reactions. CO 2 chemisorption induces ion rearrangement at the electrode–electrolyte interface, generating a measurable open‐circuit voltage shift. However, the high viscosity of the pristine IL significantly restricts ionic mobility, especially after CO 2 absorption. Dilution with propylene carbonate improves conductivity and enhances electrochemical performance. A multiparametric study was conducted under realistic working conditions, evaluating gas flow rate influence, CO 2 /N 2 selectivity, operating temperature, and long‐term stability. Moreover, the introduction of a supporting‐salt further improved ionic conductivity, interfacial properties, and pore accessibility, leading to higher capacitance and harvested power. Overall, these results highlight the potential of tailored IL‐based electrolytes for integrated CO 2 capture and energy conversion technologies.

This comprehensive review provides a detailed analysis of the potential of polymers with intrinsic microporosity (PIMs) as specialized binders for electrochemical applications. The quest for improved fuel cell and electrolyzer performance has driven extensive research on binders. Early investigations focused on conventional binders, aiming to enhance mechanical properties and adhesion. However, limitations in mass transport prompted the search for novel materials with superior gas permeability, driving interest in PIMs. Analyzing recent advancements and insights presented in the literature, we elucidate the distinct advantages offered by PIMs, such as chemical stability and enhanced gas permeability. The latter attribute is crucial for a binder in electrochemical devices, allowing efficient transport of reactants (e.g., hydrogen, oxygen) to active sites within the catalyst layers, significantly improving device efficiency and reaction rates. By synthesizing and assessing key research findings, this review aims to pave the way for future advancements in PIM-based binders for electrochemical applications, filling a notable gap in the existing literature.

The development of cost-effective and durable electrocatalysts capable of replacing platinum in proton-exchange membrane fuel cells (PEM-FCs) remains a major barrier to large-scale implementation. Here, we present a onestep laser-assisted strategy to produce a nitrogen and sulfur co-doped laser-induced graphene (N/S-LIG) electrocatalyst layer (EL). The EL is generated by CO2-laser processing of a multilayer assembly composed of a NaOHtreated polyacrylonitrile (PAN) nanofiber mat deposited onto a sulfonated poly(ether ether ketone) (SPEEK) membrane. Laser irradiation enables the simultaneous in situ carbonization of both polymers, yielding a graphene-like architecture featuring hierarchical porosity and intrinsic N/S co-doping. Structural and spectroscopic analyses reveal the formation of N-C2-S and N-C-S configurations, confirming the cooperative contribution of both heteroatoms to the catalytic function. Electrochemical measurements in acidic media demonstrate an efficient four-electron oxygen reduction reaction (ORR) pathway, with an onset potential of 0.94 V versus RHE, comparable to commercial Pt/C. Under gas-diffusion electrode operation, the N/S-LIG catalyst delivers a fivefold current increase relative to S-doped LIG, highlighting the impact of dual-heteroatom incorporation. This scalable, chemical-free method offers a direct route to high-performance, metal-free ORR catalysts, supporting the advancement of practical LIG-based electrodes for next-generation fuel cells and enabling broader adoption in energy conversion technologies worldwide applications.

ABSTRACT Polymers of Intrinsic Microporosity (PIMs) are a class of polymers characterized by a native microporous network resulting in a high surface area. PIMs also display a highly tunable and efficient gas permeability, attracting a lot of attention in several electrochemical applications. In this work. PIM‐1 was combined with a deep eutectic solvent (DES) for the production of a potentiometric sensor for CO2. This study reports the synthesis of both components, the fabrication of composite membranes via solvent casting and impregnation, and their evaluation as CO2 responsive materials together with a comprehensive characterization. The PIM‐1/DES materials demonstrated efficient CO2 capture and release behavior with open‐circuit voltage responses recorded under controlled CO2 exposure and adsorption–desorption cycling with full recovery. The membrane exhibited a response of 29 s in pure CO2 with a recovery time of 240 s. The sensors followed a logarithmic correlation between CO2 concentration and voltage variation and it showed a sensitivity of up to 9.6 mV/%CO2. These findings indicate that the developed sensor offers high reproducibility, fast response, and reliable detection of variable CO2 levels, underscoring its strong potential for practical implementation in environmental and industrial monitoring applications.

The European Union has identified fluorite (CaF2) as a critical raw material (CRM) due to its economic importance, negligible recycling, and high import dependency. This study investigates a functionalized graphene oxide (fGO) membrane for purifying wastewater containing dissolved fluorides below the solubility limit of CaF2 and the subsequent CRM recovery. While the fundamental interaction is known in batch systems, closed‐loop recovery processes using this kind of membrane remain unexplored. Utilizing fGO synthesized via a scalable, green approach, we transition beyond conventional adsorption to a dynamic membrane‐stripping cycle. Comprehensive material characterization is provided. The fGO membranes were tested in a real‐case scenario using cleanroom facility wastewater. Fluorine concentration was successfully reduced from 21 down to 1.4 mg L−1, meeting the EU/USA discharge and drinking water standards. High‐purity CaF2 powder was recovered. This work establishes a viable, non‐conventional membrane‐based approach for waste valorization, advancing circular economy principles in the semiconductor and microelectronics industries by transforming a hazardous waste into a strategic resource.

The field of hydrogen storage is one of the last frontiers in the exploitation of hydrogen-based technology. Particularly, the utilization of ammonia borane is a very promising route to solve the issue related to hydrogen storage due to the content of hydrogen up to 19.8 wt% and the stability in the ambient temperature and pressure conditions. Nevertheless, the hydrogen release from ammonia borane is quite complex under thermal stimuli, with several secondary compounds released. Alternatively, hydrolysis of ammonia borane is a simpler route to release of hydrogen in presence of water without any side reaction when a catalyst is used. This study investigates the ultrasound-assisted hydrolytic dehydrogenation of ammonia borane mediated by oxidized multiwalled carbon nanotubes (MWCNTs) as a metal-free energy-efficient catalytic system. The application of ultrasonic irradiation significantly enhanced the catalytic performance by promoting mass transport, improving water molecule activation, and increasing the dispersion and reactivity of the oxidized MWCNTs in the water medium. The oxidized MWCNTs promote the activation of ammonia borane, reducing the activation energy of the systems over 77% and reaching a remarkable hydrogen release efficiency with a conversion of up to 98%.

Functional polymers bearing ionic groups are attractive building blocks for membrane materials because they can simultaneously tailor chain mobility, interfacial interactions, and gas sorption. However, incorporating CO2-philic ionic liquids into glassy polymer matrices often leads to limited phase compatibility and morphological instability, which compromise transport performance and reproducibility.In this work, polysulfone was chemically functionalized with alkyl imidazolium pendants and employed as a polysulfone-derived polymeric ionic liquid (PIL) component in blended membranes containing pristine polysulfone and the ionic liquid 1-butyl-3-methylimidazolium succinimidate ([BMIM][Succ]). By systematically varying the pendant structure while keeping the fabrication protocol constant, we elucidate structure–property relationships linking functional group chemistry to membrane microstructure and gas transport.The imidazolium-functionalized polysulfone markedly improves ionic liquid dispersion and membrane homogeneity, enabling a concurrent increase in CO2 permeability and CO2/N2 selectivity compared to both pristine polysulfone and unmodified polysulfone/ionic liquid blends. CO2 permeability values up to ∼ 290 Barrer at 0.8 bar and 30 °C were obtained. The observed behavior is consistent with an interplay between ionic-liquid-mediated CO2 solubility and PIL-controlled diffusivity through improved phase compatibility.Overall, this study highlights polymeric ionic liquid engineering as a modular functional-polymer strategy to improve phase compatibility in ionic-liquid-containing membranes and tune gas-transport properties through controlled chemical design.

The development of sustainable hydrogen generation technologies remains a key pillar in the transition toward a sustainable society. Hydrogen storage represents one of the most intriguing challenges due to the necessity of production of safe, cheap and solid solution for small and medium applications. Chemical hydrogen carriers are very promising and ammonia borane represent a solid choice due to its high hydrogen content up to 19.6 wt% and easily hydrogen release under hydrolytic conditions. Nevertheless, ammonia borane hydrolysis required fresh water and use of catalysts increasing the environmental impact of the process. In this work, we reported the use of a complex wastewater from cheese industry, known as Scotta, rich in small organic acids as catalytic system for hydrogen generation from ammonia borane and its methylated derivatives. Scotta system showed complete hydrogen release from ammonia borane after 300 and 180 s at 40 and 50 degrees C respectively. Similarly, diand thrimethylated derivatives reached a conversion of 93.3 and 86.8% after 600s at 50 degrees C showing also a decrement of kinetic constant rate from 9 up to 40%. Furthermore, we evaluated the environmental impact of replacing fresh reagent with Scotta through life cycle assessment methodologies, proving the viability of this solution with a global warning output decrement of up 10 %.

The electrochemical reduction of CO2 (CO2RR) to value-added chemicals offers a promising route for carbon recycling and renewable energy storage. Cu-based catalysts are uniquely capable of producing multi-carbon products such as ethylene, but their selectivity is highly sensitive to their morphology. In this work, we systematically investigate the impact of Cu2O nanocube size (45-600 nm) on CO2RR performance in both alkaline flow cell and zero-gap electrolyzer, both operating at industrially-relevant current densities. The catalysts were synthesized with well-controlled geometries and edge lengths. In the flow-cell, smaller nanocubes (45-75 nm) exhibited superior selectivity toward ethylene and liquid C2 products, achieving Faradaic efficiencies toward C2 products (FEC2) of up to 50%, attributed to an optimal balance between edge and facet sites. In contrast, in the zero-gap cell, although 45 nm cubes were the most ethylene-selective, overall FEC2 was reduced and strongly influenced by operational parameters, such as anolyte composition. Long-term tests revealed a trade-off between catalyst durability and ethylene selectivity. These findings demonstrate the critical interplay between nano-structure, testing configuration, and electrolyte, and emphasize the need to assess catalyst performance under industrially-relevant conditions.

In this study, we investigate the use of hydrogen bond-stabilized amine-based mixtures (a class of systems hereafter referred to as Hydrogen Bond-Stabilized Mixtures, HBSMs; e.g., n-butylamine with glycerol or guanidinium chloride) as an alternative approach to improve carbon dioxide capture efficiency while avoiding massive solvent evaporation. CO2 capture experiments reveal that these mixtures exhibit improved sorption capacity compared to pure amines, while the presence of hydrogen bond acceptors plays a crucial role in stabilizing the systems, due to the establishment of an extended hydrogen-bond network. ATR-IR analyses confirm that CO2 capture occurs through a combination of physical and chemical absorption; on the other hand, TGA data reveal a substantial reduction in solvent evaporation rates, particularly in the n-butylamine/glycerol mixture, where evaporation decreased by more than an order of magnitude compared to pure amine. The high CO2 absorption capacity and reduced amine volatility of these mixtures open a promising avenue for more sustainable and energy-efficient carbon capture technologies, paving the way for relevant industrial applications.

Ammonia borane is a promising hydrogen storage material due to its high hydrogen content, but its use as hydrogen carrier under thermal stimuli involves the production of several byproducts, such as borazine, reducing hydrogen purity and the overall efficiency. This work is focused on the use of high-boiling-point amines to modulate ammonia borane decomposition, aiming to enhance hydrogen release and suppress volatile NxBy species. Kissinger’s equation kinetics revealed that amines significantly influence the decomposition mechanism, and TGA-IR investigation showed a maximum of 2.4 wt.% of pure hydrogen release in the presence of triphenyl amine. Furthermore, the experimental data herein discussed, together with a computational study of activation energies, allowed us to derive a detailed mechanism that leads to a foundation for further advancement in the exploitation of ammonia borane as a hydrogen carrier, suggesting that the formation of linear species is anchored to amine over the release of borazine and production of poly borazine-like species.

The development of sustainable energy storage devices, such as supercapacitors (SCs), pushes towards innovative material science solutions. This study presents Hydroxypropyl Cellulose (HPC) as a promising fluorine-free binder (FFB) alternative to traditional fluorinated binders exploited in aqueous-based electrolytic systems. HPC offers water solubility and pH stability, making it an environmentally friendly option for aqueous electrolyte-based SCs. We investigated HPC's efficacy as a binder in activated carbon-based SC electrodes due to its salt out effect, comparing it with conventional Polyvinylidene Fluoride (PVDF) binder. Electrodes were tested in acidic (1 N H2SO4), neutral (1 N Na2SO4), and basic (1 N KOH) electrolytes, with titanium current collectors. Our findings reveal that HPC-based electrodes exhibit superior uniformity and interconnectivity, as evidenced by electron microscopy and surface area measurements. Electrochemical characterizations demonstrate that HPC electrodes outperform PVDF counterparts in all tested electrolytes, particularly in terms of chemical stability in basic solutions where PVDF degrades. The HPC devices achieved specific capacitances of 22.21 F g- 1 (acidic), 17.03 F g- 1 (neutral), and 23.86 F g- 1 (basic) with over 90 % retention after 10,000 charge-discharge cycles and 160 h of floating tests. These results suggest that HPC not only ensures environmental safety but also enhances performance and durability across various pH environments. In conclusion, HPC proved to be a sustainable and effective binder for electrochemical systems with both capacitive and faradic electrodes. Future research should focus on integrating HPC with more stable current collectors to further improve devices' performance, especially in acidic media, seawater and wastewater, thus advancing the field of eco-friendly energy storage technologies.

Hydrogen is key player in the energetic transition towards a more sustainable society as a very versatile energy carrier. Nevertheless, hydrogen storage represents the main limitation to the spread of a hydrogen driven economy on a small and medium scale. Clearly, achieving this requires a balance among material engineering, system optimization, and techno-economic assessments to optimize performance, safety, and scalability. In this work we briefly and critically discuss the progress in hydrogen storage focusing on the necessity to create a bridge to overcome the actual limitations. We explore the most recent advancement in the field drawing a picture of the complex scenario of hydrogen storage in the framework to the transition to a net zero or carbon negative society providing an updated opinion on the challenges addressed and those still to be solved.

The utilization of red mud is a topic of significant interest due to its great production around the world, being the major by-product of alumina production. Nevertheless, its correct valorization is a matter of great complexity. In this work, we propose a novel use of red mud as a catalyst for the release of hydrogen from hydrolysis of ammonia borane in mild conditions. Ammonia borane is among the best chemical hydrogen carriers with a gravimetric hydrogen capability of up to 19 wt

When two solutions with different compositions are mixed, the free mixing energy is released. This principle is exploited in salinity gradient power technologies like capacitive mixing (CapMix), where mixing occurs in a supercapacitor. Since this energy release holds true also for gases, research moves in the direction of harvesting energy from anthropic CO2. To do so, it is proposed for the first time to exploit an ionic liquid (IL), both as an electrolyte and CO2 absorbing medium in a CapMix cell. The mechanism consists in flowing a CO2‐rich gas stream, alternated to a N2 stream, during the charging/discharging of two electrodes. The CO2 strongly affects the electrode/IL interface and the IL physicochemical properties thereby converting the released mixing energy into electrical energy. Unlike water‐based systems, where energy harvesting relies on electric double‐layer expansion, we propose a new mechanism based on electrochemical potential variations during CO2 capture/release, supported by molecular dynamics modeling. Key results include maximum voltage rise of 40 mV and energy and power densities of 40 μWh m−2 and 0.8 mW m−2. These findings clarify the mechanism behind the electrochemical phenomena occurring when CO2 interacts with IL and open the way to a new generation of electrochemical systems to harvest energy from CO2 emission.

Hydrogen production from biomass gasification has emerged as a strategic pathway for achieving carbon-neutral energy systems, circular resource utilization, and sustainable fuel generation. As global energy systems transition toward renewable sources, biomass-derived hydrogen represents a cornerstone of waste valorization, negative-emission bioenergy, and green hydrogen economies. Among all technologies, hydrogen production through gasification is one of the most consolidated routes with plenty of operative industrial-scale plants. The field of gasification is quite complex, and this comprehensive review describes the current scientific and technological achievements of biomass gasification for hydrogen production, describing the effect of feedstock, reactivity phenomena, reactor design, and catalyst systems. Furthermore, we report on a quantitative analysis regarding the operative cost of gasification of biomass compared with green hydrogen production and methane reforming. We provide a complete and synthetic picture for one of the most critical fields in the hydrogen economy that can actively promote a transition towards a more sustainable society.

Concerning the emerging power-to-gas technologies, which are considered the most promising technology for seasonal renewable energy storage, Underground Hydrogen Storage (UHS) has gained attention in the last few years. For safe and efficient storage, possible hydrogen losses due to dissolution into the aquifer must be estimated accurately. Due to safety concerns, experimental measurements of hydrogen solubility in brine at reservoir conditions are limited. In this study, a PVT cell is used to characterize the solubility of hydrogen and its mixtures with methane in saline water/brine. The experiments were carried out at 45, 50, and 55°C and from 1 bar up to 500 bar, mimicking a significant range of possible reservoir conditions. Two brine samples representative of two different reservoirs were tested. Two mixtures of methane and hydrogen (10 mol% H2 and 50 mol% H2, respectively) were considered, along with pure hydrogen, to account for the presence of methane in the primary phase of hydrogen storage in a depleted gas reservoir. In the current paper, a comparison of the experimental results with literature models is provided. At the experiment conditions, the impact of the differences in the composition of the two analyzed brines as well as the impact of the analyzed range of temperatures was not significant. Conversely, a non-negligible variation in terms of the slope of the solubility curve was observed as a function of the gas mixture composition: the curve increased more steeply as the percentage of hydrogen reduced.

Hydrogen storage systems have become of great interest particularly especially for those that conjugate a high storage capacity together with high safety standards. Chemical storage using amino borane has attracted a great interest and ammonia borane is playing a major role in the field due to the hydrogen storage capacity up to 19 wt %. Nevertheless, the hydrogen evolution from ammonia borane is a matter of great complexity and hydrolytic methods represent the simpler way to approach it. Actually, the ammonia borane hydrolysis is carried out by using complex catalysts not containing critical raw materials and/or noble metals. In the present work, we report the production of iron based heterogeneous catalyst support onto carbonized pig manure. The complexity of this waste stream was very helpfully to provide an active surface for the anchoring of iron nanoparticles and promoting the hydrogen evolution form hydrolysis of ammonia borane reaching a conversion of 98.3 % at 50 degrees C with an iron loading of 10 wt%. The catalytic system reduced the activation energy of the reaction up to 51 % increasing the kinetic constant of the reaction of one order of magnitude. Furthermore, the stability of the catalytic system was preserved after three cycles without appreciable changes.

Abstract Hydrogen has been identified as an energy carrier that could play a major role in decarbonization. Large-scale hydrogen storage is required to face future challenges in terms of energy and environmental transition. Underground Hydrogen Storage (UHS) in depleted gas reservoirs is broadly recognized as a promising strategy to safely store large quantities of hydrogen, which can be injected into the porous rocks as a pure component (100% of H2) or as a mixture with methane. In order to properly design storage activity in a depleted gas reservoir, it is extremely important to define a reliable 3D reservoir dynamic model able to simulate the behavior of the system under all the possible considered operating conditions. To properly represent the interaction between injected hydrogen or mixture with the reservoir fluids, the Equations of State adopted in the compositional simulation must be validated against laboratory data in the pressure and temperature ranges representative of possible operating conditions, and if necessary, properly calibrated. In this paper, we provide the results of experiments carried out on H2-CH4 mixtures within ranges of temperature and pressure conditions representative of depleted gas candidates for storage activities. Constant Mass Expansion (CME) tests were performed using a PVT cell. Pressures up to 300 bar and a temperature range from 30 to 60°C, representing the typical range for a gas storage reservoir in Italy and Europe, were applied. Four different mixtures were considered: pure H2, 50 mole% H2-50 mole% CH4, 10% H2-90 mole% CH4, pure CH4. Results are represented in terms of gas compressibility factor (z factor) curves as a function of pressure for different temperatures and compositions. Furthermore, the obtained results are compared with the GERG-2008 equation of state (EoS). In the considered pressure and temperature ranges, the GERG-2008 EoS provides a satisfactory match with the experimental data for all the considered cases.