Search Results (4,650)

Despite being frequently proposed as a low-carbon solution for wastewater treatment and solar fuel production, the feasibility of photocatalytic processes in large-scale deployments remains unclear. This review evaluates the scalability of photocatalytic technologies by synthesizing a decade (2015–2025) of techno-economic analysis (TEA) and life-cycle assessment (LCA) studies. Using a systematic search and programmatic screening, 77 assessment-focused publications were identified from an initial corpus of 854 studies. Across applications, TEA and LCA consistently highlight two dominant barriers to scale-up: high electricity demand in UV-driven systems and significant cradle-to-gate impacts associated with catalyst synthesis, particularly for nanostructured materials. When solar irradiation replaces artificial light, environmental and economic hotspots shift from energy use to material production, catalyst durability, and reuse assumptions. Wide variability in reported costs and impacts reflects heterogeneous methodologies, limited pilot-scale data, and a lack of standardized reporting. Overall, assessment-based evidence indicates that photocatalysis is not yet ready for widespread industrial deployment as a large industrial process. However, continuous advances in solar-driven reactor design, low-impact and circular catalyst synthesis, hybrid process integration, and harmonized TEA/LCA frameworks could substantially improve its prospects for scalable, climate-positive implementation, especially in the context of emerging green energy alternatives. Full article

Egg white was chosen as a renewable, non-toxic agent for the synthesis of FeMn₂O₄ spinel pre-catalysts to avoid the use of critical transition metals such as Ni and Co. However, synthesizing phase-pure FeMn₂O₄ remains challenging due to (i) the requirement of low oxygen partial pressures to counter rapid reoxidation of Mn₃O₄ in the presence of iron oxides, which can be achieved by the preferred oxidation of the egg white during the calcination, and (ii) the probable formation of Fe₃O₄ and Mn₃O₄ during intermediate steps in the reaction, leading to multiphase spinel formation caused by a miscibility gap between the spinels. In contrast, spinels with Ni, Co, Zn, or Al are phase-pure. Egg white has significant environmental impacts in the synthesis of all spinel manganites, as assessed from a life-cycle perspective, which can exceed those of petroleum-based agents such as ethylenediaminetetraacetic acid (EDTA) in most impact categories. Therefore, our results show that the investigated synthesis route is not more sustainable, and we demonstrate that implementing quantitative evaluation of environmental impacts already at an early stage is essential to determine whether a synthesis is truly sustainable. Full article

This work reports on the synthesis and ring-opening metathesis polymerization (ROMP) of two novel homologous sulfonyl-containing norbornene dicarboximide monomers, specifically, N-4-(trifluoromethylsulfonyl)phenyl-norbornene-5,6-dicarboximide (1a) and N-4-(trifluoromethylsulfonyl)phenyl-7-oxanorbornene-5,6-dicarboximide (1b) using the Grubbs 2nd generation catalyst (I). The polymers are thoroughly characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), thermomechanical analysis (TMA), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and X-ray diffraction (XRD), among other techniques. A comparative study of gas transport in membranes based on these ROMP-prepared polymers is performed and the gases studied are hydrogen, oxygen, nitrogen, carbon dioxide, methane, ethylene and propylene. It is found that the presence of sulfonyl pendant groups in the polymer backbone increases the gas permselectivity in slight detriment of the gas permeability compared to a polynorbornene dicarboximide lacking sulfonyl groups. The membrane of the sulfonyl-containing polymer with an oxygen heteroatom in the cyclopentane ring, 2b, is also found to have one of the largest permselectivity coefficients reported to date for the separation of H₂/C₃H₆ in glassy polynorbornene dicarboximides. Full article

The oxygen evolution reaction (OER) in water splitting involves complex multi-electron–proton transfer processes and represents the rate-determining step limiting overall electrolysis efficiency. Developing non-noble-metal catalysts with high activity and stability is therefore essential. Herein, a heterogeneous synthesis strategy was employed to in situ construct an iron-rich layered sulfate precursor (Fe_0.42Co_0.58-SO₄/NF) on nickel foam, which underwent deep self-reconstruction in alkaline electrolyte to form nanoflower-like Fe_0.42Co_0.58OOH/NF. The optimized catalyst maintained its iron-rich composition and hierarchical structure, delivering outstanding OER performance with an overpotential of 220 mV at 10 mA·cm⁻², a Tafel slope of 31.9 mV·dec⁻¹, and stability exceeding 12 h at 600 mA·cm⁻². Synchrotron analyses revealed dynamic transitions between mono-μ-O and di-μ-O Fe–M (M = Fe, Co) oxygen bridges during reconstruction, which enhanced both structural robustness and active-site density. The Fe-rich environment promoted the formation of Fe³⁺–O–Fe³⁺ units that synergized with Co⁴⁺ species to activate the lattice oxygen mechanism (LOM), thereby accelerating OER kinetics. This work elucidates the key role of oxygen-bridge geometry in optimizing catalytic activity and durability, providing valuable insights into the rational design of Fe–Co-based non-noble-metal catalysts with high iron content for efficient water oxidation. Full article

4,5-Dihydro-2H-pyridazin-3-ones (DHPDOs) are important synthetic as well as naturally occurring heterocycles. We herein report the synthesis of various 4-monofunctionalized 4,5-dihydro-2H-pyridazin-3-ones and their use as starting materials to access 4,4-disubstituted dihydropyridazin-3-ones in an asymmetric fashion. By using chiral ammonium salt phase-transfer catalysts, conjugate additions of these scaffolds to classical acrylate-based Michael acceptors, as well as quinone methides, can be carried out with moderate to good enantioselectivities and in reasonable yields, affording a new pathway to dihydropyridazin-3-one derivatives with an all-carbon stereocenter. Full article

In a quest to develop more sustainable polymers, decoupling their production from fuel-based resources and searching for alternative greener synthetic pathways are important priorities. Among the numerous polymers that fall into this category are furan-based polyesters. Besides the origin of polymers, their synthesis is another critical topic to consider regarding the overall greenness of the final product. However, despite several studies focusing on bio-based alternatives, such as poly(alkylene 2,5-furandicarboxylate)s, their synthesis still relies on air- and water-sensitive metal-based catalysts and is typically carried out under harsh conditions. This study explores an alternative approach with the application of eutectic solvents (ES) as catalysts for a more sustainable approach for synthesising furan-based polyesters, specifically poly(ethylene 2,5-furandicarboxylate) (PEF), as well as poly(trimethylene furandicarboxylate) (PTF) and poly(butylene furandicarboxylate) (PBF). Two different ES were evaluated as catalysts; the best results were obtained with urea and zinc acetate ES (U:Zn(OAc)₂, 4:1 mol:mol). The resulting polymers were analysed for their structure, molecular weight, and thermal properties. Full article

Reaction conditions (RCs) are a crucial part of reaction definition, and their accurate prediction is an important component of chemical synthesis planning. The existence of multiple combinations of RCs capable of achieving the desired result complicates the task of condition recommendation. Herein, we propose a conditional variational autoencoder (CVAE) generative model to predict suitable RCs. The CVAE model has been customized to generate diverse sets of valid conditions, ensuring high flexibility and accuracy, while circumventing the necessity for enumeration or combinatorial search of potential RCs. The efficacy of the CVAE approaches was evaluated using hydrogenation reactions and other H₂-mediated reactions, predicting the set of catalysts, additives (acid, base, and catalytic poison), ranges of temperature, and pressure. The CVAE models predicted conditions with different “heads”, each corresponding to specific condition components, and their respective losses. CVAE models were tested on two datasets: a small one containing 31K reactions with 2232 potential conditions’ combinations and a big one having 196K reactions with ~7 × 10⁴² potential conditions’ combinations to evaluate the model’s ability to predict varying complexity and diversity conditions. To optimize the accuracy of the models, we experimented with three latent distribution variants—Gaussian (g-CVAE), Riemannian Normalizing Flow (rnf-CVAE), and Hyperspherical Uniform (h-CVAE). In our experiments, the h-CVAE model demonstrated robust overall performance, making it the optimal choice for scenarios requiring high accuracy across multiple top-k predictions. Benchmarking analyses demonstrated the high performance of the CVAE models compared to state-of-the-art reaction condition prediction approaches. Full article

Catalytic transfer hydrogenation (CTH) provides a practical and sustainable approach for reducing unsaturated compounds, serving as an alternative to high-pressure H₂ in laboratory and fine chemical contexts. This broad reaction class includes asymmetric transfer hydrogenation (ATH), a key strategy in enantioselective synthesis due to its operational simplicity, high stereocontrol, and compatibility with sensitive functional groups. A central variable governing CTH efficiency is the role of bases, which may function as essential activators, co-hydrogen donors, or be entirely absent depending on the catalytic system. This review provides a comparison of base-assisted, base-free, and base-as-co-hydrogen-donor CTH methodologies across diverse metal catalysts and substrates. We highlight how bases such as triethylamine, K₂CO₃, and NaOH facilitate catalyst activation, modulate hydride formation, and tune reactivity and selectivity. The dual function of bases in formic-acid-driven systems is examined alongside synergistic effects observed with mixed-base additives. In contrast, base-free CTH platforms demonstrate how tailored ligand frameworks, metal-ligand cooperativity, and engineered surface basicity can eliminate the need for external additives while maintaining high activity. Through mechanistic analysis and cross-system comparison, this review identifies the key structural, electronic, and environmental factors that differentiate base-assisted from base-free pathways. Emerging trends—including greener hydrogen donors, advanced catalyst architectures, and additive-minimized protocols—are discussed to guide future development of sustainable CTH processes. Full article

This paper presents the synthesis and characterization of anionic rhodium(I) complexes obtained by the reaction of a homogeneous Wilkinson catalyst or a rhodium cyclooctadiene dimer with ionic liquids as precursors. All newly produced complexes were characterized spectroscopically (NMR, ESI-MS, FT-IR) and their thermal stability was examined (TGA, melting point). Moreover, their catalytic activity was determined in the hydrosilylation of octene or allyl glycidyl ether with 1,1,1,3,3,5-heptamethyltrisiloxane and in the hydroboration reaction of styrene with pinacolborane (HBpin). All catalysts used were insoluble in the reactants, which allowed for their isolation and repeated use. Their activity was compared in subsequent 10 (hydrosilylation) or 5 (hydroboration) catalytic cycles. The obtained results allowed the selection of the most effective catalytic systems, which can be a real alternative to traditional homogeneous catalysts, offering greater ease of recovery and reuse. Full article

The efficiency and durability of oxygen evolution reaction (OER) catalysts at industrially relevant current high densities are critical determinants of energy consumption and operating cost of alkaline electrolyzers. However, Raney nickel, widely adopted as a commercial electrode, still lacks sufficient intrinsic activity, leading to excessive energy consumption. Herein, a facile electro-oxidation engineering strategy with strong industrial compatibility is developed, and constructs a high-performance OER electrode Raney Ni–Fe³⁺ without compromising the inherent stability and scalability. The optimized electrode achieves 100 mA/cm² at a small overpotential of 265.1 mV with a Tafel slope of 36.17 mV/dec. It further demonstrates exceptional durability, remaining stable for at least 100 h at 300 mA/cm². By in situ constructing Fe³⁺-doped NiOOH phases on the Raney Ni framework, the proposed strategy effectively realizes the precise synthesis of high-performance active layers and greatly enhances the intrinsic catalytic activity. This work provides a new perspective for improving alkaline electrolyzer efficiency and contributing to the large-scale advancement of green hydrogen technology. Full article

Water pollution from textile effluents poses serious environmental risks, particularly due to persistent anionic dyes such as Reactive Black 5 (RB5). This study demonstrates that simple deposition of Y₂O₃ onto commercially available, biobased TiO₂ (bTiO₂) significantly enhances photocatalytic degradation efficiency under simulated sunlight, suppressing rapid recombination of electron–hole pairs. Addressing a key research gap, the proposed method replaces expensive nanoscale precursors and complex synthesis routes typically used for Y₂O₃/TiO₂ systems with a low-cost, straightforward approach involving weak complexation and co-precipitation. The resulting Y₂O₃-bTiO₂ composite was characterized using FTIR, XRD, SEM, EDX, TEM, XPS, and UV-DRS techniques, confirming efficient incorporation of Y₂O₃ on the TiO₂ surface. Photocatalytic experiments revealed that nanoparticles calcined at 700 °C achieved complete RB5 degradation within 60 min—reducing the reaction time by half compared to undoped bTiO₂. Systematic studies of initial dye concentration, catalyst loading, and irradiation time confirmed that the degradation followed pseudo-first-order kinetics with a rate constant of 0.064 min⁻¹ (R² = 0.98). Calculated quantum yields corroborated the reduced electron–hole recombination induced by Y₂O₃ deposition. These findings highlight the novelty and practicality of the developed Y₂O₃-bTiO₂ photocatalyst as an efficient, affordable, and environmentally sustainable material for the degradation of industrial dyes. Full article

Due to its significant environmental impact, the built environment faces growing pressure to transition toward more sustainable practices. Biomimicry, a novel field of practice that entails design and innovation inspired by nature’s time-tested strategies, offers a promising pathway to enhance sustainability in the construction industry. Hence, this study examines the perceived benefits of applying biomimicry principles in the construction sector, aiming to identify the key dimensions that underpin its transformative potential. An exploratory factor analysis (EFA) was conducted using data collected through a structured questionnaire survey, which contained 18 indicators derived from a targeted literature synthesis. The questionnaire was administered to 120 purposively sampled, duly registered, practising construction and biomimicry professionals in South Africa. The instrument captured perceptions of the environmental, economic, and socio-functional benefits of adopting and implementing biomimicry. The EFA revealed four principal factors: socio-economic and health, ecological resilience, performance enhancement and green market efficiency. These four factors cumulatively accounted for approximately 70% of the total variance, indicating a strong internal structure of perceived benefits. The findings demonstrate that stakeholders perceive biomimicry as a tool for reducing environmental footprints and as a catalyst for innovation, circularity, and regenerative design practices in the built environment. This research contributes to the emerging discourse on biomimicry in the built environment by providing empirical evidence on its multifaceted value. It highlights the importance of integrating natural design intelligence into construction to foster more adaptive, efficient, resilient and sustainable systems. The paper recommends policy support, interdisciplinary collaboration, and further research to operationalise biomimicry within mainstream construction processes. Full article

FeCoNiCu(Cr, Mn, La, Ce)-Al high-entropy alloys (HEAs) were prepared via a combined centrifugal casting–self-propagating high-temperature synthesis process to serve as multifunctional catalyst precursors. The findings indicated that even with aluminum content reaching 50 wt %, the typical bcc structure inherent to HEAs was preserved. Doping additions (Cr, Mn, La, and Ce) led to pronounced microstructural changes, including alterations in morphology, porosity, and elemental distribution, while the primary phase constituents of the FeCoNiCuAl-based alloys remained consistent. It was found that La and Ce exhibited poor bulk incorporation into the HEAs, evidenced by a low surface content. Aluminum leaching and hydrogen peroxide stabilization converted these precursors into catalysts. These catalysts demonstrated high activity in the deep oxidation of propane and CO. The FeCoNiCu catalyst achieved the best results for CO oxidation, reaching 100% CO conversion at 250 °C. For propane oxidation, the FeCoNiCuCrMn catalyst was the most active, yielding 100% CO conversion at 300 °C and 97% propane conversion at 400 °C. Full article

High-valent metal species (iron, manganese, cobalt, copper, and ruthenium) based advanced oxidation processes (AOPs) have emerged as sustainable technologies for water remediation. These processes offer high selectivity, electron transfer efficiency, and compatibility with circular chemistry principles compared to conventional systems. This comprehensive review discusses recent advances in the synthesis, stabilization, and catalytic applications of high-valent metals in aqueous environments. This study highlights their dual functionality, not only as conventional oxidants but also as mechanistic mediators within redox cycles that underpin next-generation AOPs. In this review, the formation mechanisms of these species in various oxidant systems are critically evaluated, highlighting the significance of ligand design, supramolecular confinement, and single-atom engineering in enhancing their stability. The integration of high-valent metal-based AOPs into photocatalysis, sonocatalysis, and electrochemical regeneration is explored through a newly proposed classification framework, highlighting their potential in the development of energy efficient hybrid systems. In addition, this work addresses the critical yet underexplored area of environmental fate, elucidating the post-oxidation transformation pathways of high-valent species, with particular attention to their implications for metal recovery and nutrient valorization. This review highlights the potential of high-valent metal-based AOPs as a promising approach for zero wastewater treatment within circular economies. Future frontiers, including bioinspired catalyst design, machine learning-guided optimization, and closed loop reactor engineering, will bridge the gap between laboratory research and real-world applications. Full article

In this study, CuO nanoparticles were synthesised by chemical precipitation assisted by ultrasonic irradiation (UI), a rapid and environmentally friendly procedure without high temperature that enhances the sustainability of the synthesis process. They were also employed as a catalyst to activate peroxydisulfate (PDS) in the removal of ciprofloxacin (CIP) from a polluted solution. The effects of various factors, such as CIP concentration, catalyst dosage, PDS concentration, and initial pH, on the efficiency of this contaminant treatment were investigated. Under optimal conditions, CIP and TOC removal reached 100% and 49%, respectively, after only 30 min of reaction time and using high initial concentrations of CIP (20 mg/L), PDS (0.5 mM), and CuO (0.5 g/L) in pH (10). For the best set of processing conditions, pseudo-first-order reaction rate kinetics can be assumed and characterised. The possible degradation pathway of CIP is also suggested. Furthermore, by quenching experiment, the presence of O₂⁻*, *OH, and SO₄⁻* were identified, with O₂⁻* being a radical species with great impact on CIP removal. This study demonstrates that, in alkaline environments, ultrasonically synthesised CuO can effectively activate PDS for the degradation of CIP, achieving total removal within 30 min. The results indicate that UI-synthesised CuO is a very promising catalyst for the removal of emerging organic pollutants. Full article