Search Results (2,108)

The development of a green hydrogen industry is a strategic priority for Russia’s energy transition, yet the dynamics of scaling up this nascent sector remain poorly understood. This study uses agent-based modeling (ABM) to simulate the co-evolution of Russia’s electricity, hydrogen, and electrolyzer sectors over 2024–2050. The model incorporates three types of heterogeneous agents (power producers, hydrogen producers, and electrolyzer manufacturers) operating under bounded rationality. Four scenarios are examined across 50 Monte Carlo runs each, varying the electrolyzer learning rate (10–25%), willingness to pay for green hydrogen (2–6 $/kg), and government support intensity. The results reveal an endogenous three-phase development pattern: Phase I (2024–2028) dominated by renewable capacity build-up reaching ~30 GW; Phase II (2029–2040) characterized by rapid electrolyzer deployment scaling to 14.5 GW; and Phase III (2041–2050) marked by stabilization at approximately 30 GW producing 1.12 Mt/year at 3.1 $/kg. Two critical thresholds are identified: renewable capacity exceeding 30–38 GW and low-cost electricity above 4–7 TWh/year. The electrolyzer learning rate emerges as the most influential parameter, while the pessimistic scenario confirms market failure without a green premium (WTP < 2 $/kg). Strategic investment losses of 2–6 billion USD are necessary catalysts for industry emergence. Russia’s 2030 production target (0.55 Mt) is found structurally infeasible under all scenarios. Full article

Thermochemical/catalytic co-processing of biomass and solid wastes is a promising route for waste valorization, low-carbon energy recovery, and the co-production of fuels, chemicals, and carbon materials. Conventional pathways, including pyrolysis, gasification, liquefaction, and carbonization, provide the basic framework for mixed-feed conversion. Emerging routes, such as flash Joule heating, microwave-assisted conversion, plasma processing, supercritical water treatment, solar-driven systems, and machine-learning-assisted optimization, further expand opportunities for process intensification and selective upgrading. Owing to feedstock complementarity, including hydrogen donation from plastics, catalytic effects of ash minerals, and interactions among reactive intermediates, co-processing can enhance deoxygenation, hydrogen generation, aromatization, and carbon utilization. Major challenges remain, however, including feedstock heterogeneity, reactor scale-up, catalyst stability, and the limited transferability of laboratory-scale synergy to realistic waste streams. Future progress should therefore focus on continuous validation, mechanistic clarification, and integrated techno-economic, life-cycle, and data-driven assessments. Full article

Biodiesel is a sustainable and promising alternative energy source produced from renewable raw materials using various methods. One effective approach is simultaneous esterification and transesterification, which relies on suitable catalysts that can be either homogeneous or heterogeneous. Homogeneous catalysts (acid or base) offer high activity but are corrosive and difficult to recover, necessitating energy-intensive processes such as aqueous quenching and neutralization, which can lead to soap formation and stable emulsions. By comparison, heterogeneous catalytic systems overcome many of these challenges due to their ease of recovery, reusability, and simplified product separation, which collectively enhance economic viability and environmental sustainability. This review highlights recent progress in the application of zeolite-based solid catalysts for biodiesel synthesis, with particular emphasis on their use in converting waste cooking oil and other low-cost feedstocks, including non-edible oils, non-food biomass sources, algal resources, and genetically engineered microorganisms. Key factors such as catalytic activity, selectivity, catalyst loading, and reusability are discussed, highlighting the advantages of zeolites due to their unique crystal structure, high thermal stability, and ease of product recovery. Overall, this review underscores the challenges and opportunities in zeolite-based catalysis to provide a comprehensive understanding of its potential to enhance the efficiency and scalability of biodiesel production. Full article

Nowadays, organic, inorganic, and microbial pollutants are listed as a substantial threat to the environment as well as public health, leading to water contamination. Green technologies such as photocatalytic and photoelectrocatalytic processes have appeared as favorable tools for water remediation, leading to effective degradation of pollutants under environmentally relevant operating conditions. With the rapid development of photocatalysis in the 21st century, heterogeneous catalysts have been extensively engineered to improve light utilization and promote surface redox reactions. This review presents an overview of recent advances in the synthesis, design, and application of heterogeneous catalysts for water purification. Key reaction mechanisms, material modifications, and hybrid processes are discussed. Also, the growing need for environmentally friendly, sustainable, and cost-effective catalytic materials is underlined. Attention was given to the role of molecular modeling in understanding catalytic mechanisms and guiding the design of efficient and sustainable catalytic materials. By critically analyzing contemporary progress, limitations, and emerging trends, this review directs future research activities towards increasingly efficient and scalable water purification methods. Full article

This paper systematically reviews the recent advances in catalytic systems and reaction mechanisms for the synthesis of crotonaldehyde via aldol condensation using acetaldehyde as the feedstock. Firstly, the structural characteristics, reactivity, and important applications of crotonaldehyde in fine chemicals are outlined, with particular emphasis on the limitations of traditional homogeneous base-catalyzed processes, such as difficulty in separation and environmental pollution caused by waste streams. On this basis, heterogeneous catalytic systems are discussed in detail, focusing on the progress of metal oxides, aluminosilicate zeolites, and heteroatom zeolites in regulating acid–base properties, active site structures, and reaction pathways. Furthermore, the typical carbanion mechanism and direct condensation mechanism in aldol condensation are summarized, and the catalyst deactivation and by-product formation mechanisms are analyzed. Finally, perspectives on the construction of efficient and green catalytic systems and future research directions are proposed, aiming to provide theoretical guidance for process optimization and catalyst design in crotonaldehyde synthesis from acetaldehyde. Full article

The development of efficient, sustainable, and low-cost catalysts for wastewater treatment remains a major environmental challenge. In this work, Zn-doped CuO nanostructures were successfully synthesized via a green route using Aloysia citrodora leaf extract as a natural reducing and stabilizing agent. The structural and morphological properties of the prepared catalysts were systematically characterized by XRD, Raman spectroscopy, FTIR, SEM, and EDX analyses. The results revealed the formation of highly crystalline monoclinic CuO nanoparticles, whose defect density and surface properties were significantly modified by Zn incorporation. The catalytic performance of the synthesized materials was evaluated through the heterogeneous Fenton-like degradation of Rhodamine B in aqueous solution under dark conditions. The Zn-doped CuO catalyst exhibited outstanding degradation efficiency (~99.97%) within only 30 min, using a low catalyst dosage of 15 mg and a minimal H₂O₂ amount of 25 μL. The enhanced catalytic activity is attributed to the synergistic interaction between Zn-induced lattice defects and the Cu²⁺/Cu⁺ redox cycle, which promotes efficient H₂O₂ activation and •OH radical generation. Radical scavenging experiments confirmed the dominant role of hydroxyl radicals in the degradation process. Compared with previously reported CuO-based catalysts, the present system demonstrates superior performance in terms of reaction rate, oxidant consumption, and energy efficiency. These findings highlight the potential of Zn-doped CuO synthesized via green chemistry as a promising and sustainable catalyst for advanced wastewater treatment applications. Full article

Advanced oxidation processes based on photo-Fenton chemistry have gained increasing attention as effective treatment alternatives for the removal of pharmaceutical contaminants from water and wastewater systems. However, large-scale implementation remains constrained by operational requirements, limited mineralization efficiency, and challenges associated with process stability and selectivity. This review provides a critical assessment of recent advances (2022–2025) in conventional photo-Fenton and hybrid systems, including photocatalysis/photo-Fenton and sono-photo-Fenton processes, with emphasis on their performance in water and wastewater treatment applications. The removal of non-steroidal anti-inflammatory drugs, antibiotics, pharmaceutical mixtures, and real wastewater matrices is analyzed considering catalyst configuration, irradiation sources, oxidant utilization, and operating conditions relevant to practical treatment scenarios. Conventional homogeneous Fe²⁺/H₂O₂ systems enable rapid contaminant degradation but typically require acidic conditions and show limited mineralization efficiency. In contrast, iron-complexed and heterogeneous catalysts allow operation under near-neutral pH and visible-light irradiation, improving applicability in realistic water treatment systems. Hybrid photocatalysis/photo-Fenton processes enhance treatment efficiency through synergistic generation of reactive oxygen species, while ultrasound-assisted systems further intensify oxidation rates and contaminant removal. Special attention is given to oxidation mechanisms, catalyst stability, transformation products, and toxicity evolution to identify the key factors controlling treatment performance. Finally, current technological limitations, operational challenges, and design considerations for process integration, scale-up, and sustainable implementation in water and wastewater treatment are discussed. Full article

The global demand for biodiesel production is steadily increasing. Conventional homogeneous basic catalysts, while widely used in the industry, face significant drawbacks, such as the requirement for high-quality feedstock, excessive waste generation, and multiple purification steps. In this study, an acidic silane (IM-CPTMS-BS-H₂SO₄) containing imidazolium and sulfonic groups was synthesized. Heterogeneous catalysts were then prepared by anchoring varying proportions of the silane onto SBA-15 mesoporous solids. These materials were characterized by FTIR, ¹³C and ²⁹Si NMR, TGA, XRD, CHNS and acidity measurements. The catalysts were evaluated in the transesterification of methyl acetate with ethanol, with increasing catalytic conversions with the amount of grafted IM-CPTMS-BS-H₂SO₄. Furthermore, increasing the catalyst loading (from 2% to 5% wt.) and the reaction temperature (from 50 °C to 65 °C) led to higher methyl acetate conversion rates. Full article

Increasing water demand and the rising complexity of wastewater matrices, driven by pharmaceuticals, personal care products, and recalcitrant industrial contaminants, require advanced catalytic solutions capable of efficient mineralization under sustainable conditions. Solar-driven processes have attracted growing attention; however, ultraviolet disinfection, heterogeneous photocatalysis, and photo-Fenton systems are commonly treated as independent approaches without mechanistic integration. This review presents a unified photonic–thermal catalytic framework for solar-driven wastewater treatment, emphasizing the interplay between photon absorption, charge-carrier separation, reactive oxygen species generation, and radical-mediated oxidation pathways. The contributions of ultraviolet, visible, and infrared radiation are analyzed in terms of catalyst activation, persulfate and ozone activation mechanisms, and temperature-enhanced reaction kinetics governed by Arrhenius behavior. Particular attention is given to photothermal effects that modulate surface reaction rates, mass transfer, and catalyst stability. By integrating mechanistic insights with reactor-level considerations, this work provides a rational basis for the design of robust solar catalytic systems with enhanced activity, selectivity, and scalability for real wastewater applications. Full article

This review explores the catalytic conversion of carbon dioxide (CO₂) into glycerol carbonate (GC), positioning this pathway as a sustainable strategy that couples environmental mitigation with the valorization of surplus glycerol from biodiesel production. Glycerol carbonate maintains extensive industrial utility as a green solvent, chemical intermediate, and functional component in polymers, cosmetics, and packaging. Distinct from prior literature, this study specifically evaluates the use of amorphous silica from rice husk ash (RHA) as a sustainable, low-cost support, analyzing the synergistic effect between Nb₂O₅, NiO, and ionic liquids in hybrid catalyst architectures. The review evaluates diverse catalytic frameworks, with a primary focus on heterogeneous systems. Silica-based materials are highlighted, particularly those synthesized from rice husk ash, which is an abundant amorphous silica source. The sol–gel method is identified as a robust route for engineering porous matrices with high surface areas and tunable structural properties. Furthermore, the doping of silica with metal oxides, such as niobium oxide (Nb₂O₅) and nickel oxide (NiO), is discussed as a strategic approach to introduce synergistic acid–base sites and redox properties that facilitate CO₂ activation. The integration of ionic liquids into hybrid systems is also examined as a promising frontier to enhance reaction kinetics and selectivity. Finally, this review delineates the nexus between agro-industrial waste management and the reduction in greenhouse gas emissions, proposing a circular economy framework for the biodiesel value chain. Full article

The cleavage of cumene hydroperoxide (CHP) via the Hock rearrangement is a cornerstone process in the chemical industry, responsible for over 90% of global phenol and acetone production. Despite its industrial significance, the conventional use of homogeneous sulfuric acid catalysis presents critical drawbacks, including severe equipment corrosion, generation of hazardous waste, and the need for complex neutralization steps. This review explores the transition toward heterogeneous solid acid catalysts as a sustainable alternative, emphasizing the relationship between catalyst structure, surface acidity, and reaction performance. Key catalyst families—such as ion-exchange resins, zeolites, and heteropolyacids—are systematically evaluated, with a focus on how Brønsted acid site density and porous architecture influence catalytic activity and selectivity. Particular attention is given to deactivation mechanisms, including coking, leaching of active species, and poisoning by inorganic cations, alongside mitigation strategies enabled by rational catalyst design and regeneration protocols. Additionally, we highlight recent progress in reactor engineering, particularly the integration of solid acid catalysts in reactive distillation and microchannel configurations. These insights offer a strategic perspective for developing more efficient and environmentally benign industrial processes for the Hock cleavage of cumene hydroperoxide. Full article

Bentonite-supported iron catalysts (Bent-Fe) were synthesized and investigated for their application in the heterogeneous electro-Fenton process for amoxicillin (AMX) degradation. The synthesized catalyst was thoroughly characterized using BET, XRD and SEM-EDS analyses, which confirmed the successful incorporation and homogeneous distribution of iron within the bentonite matrix. Acid activation significantly increased the specific surface area from 32 to 216 m² g⁻¹, while subsequent iron impregnation reduced it to 152 m² g⁻¹, indicating effective iron immobilization within the porous structure. High-resolution XPS analysis of Bent-Fe indicates that the Fe(III) is embedded within the bentonite matrix. These results confirm the successful formation of the Fe(III)-bentonite catalyst, in which both components retain their structural integrity. Adsorption experiments showed that AMX adsorption onto Bent-Fe was negligible over the investigated pH range. Despite this limited adsorption, the electro-Fenton/Bent-Fe system exhibited high degradation efficiencies reaching 95% at pH 3 and 91% at pH 6 after 120 min of electrolysis. These degradation rates corresponded to chemical oxygen demand (COD) removals of 55% and 39%, respectively. The comparable performance near-neutral pH conditions demonstrates the feasibility of operating the heterogeneous electro-Fenton process at near-neutral pH conditions, highlighting the effectiveness of bentonite as a support material for iron stabilization and catalytic degradation of AMX. Full article

The homogeneous nature of L-proline organocatalysts restricts their application in aldol condensation due to poor recyclability and stability. Herein, L-proline was heterogenized by ionic intercalation into Mg–Al layered double hydroxides (LDHs), yielding a series of proline-intercalated catalysts with tunable layer structures. Co-precipitation and memory-effect reconstruction strategies were employed to regulate interlayer spacing and proline loading. The resulting catalysts exhibited efficient performance in the aldol condensation of furfural with ketones under mild conditions. The reconstructed catalyst re-Mg₄Al₁P achieved a furfural conversion of 88.67% and a total product yield of 85.54% at room temperature, with product selectivity exceeding 95%. Structural characterizations confirmed that proline was stabilized within the LDH interlayers via R–COO—Mg electrostatic interaction while preserving the secondary amine active site. Mechanistic analysis indicated that the reaction proceeded through enamine- or enol-mediated pathways depending on water content, while the layered LDH framework imposed geometric confinement that suppressed side reactions. Catalyst deactivation in aqueous systems was mainly attributed to proline leaching rather than structural collapse. Full article

Methane, as an abundant and relatively clean resource, has primarily been converted into various chemical products via indirect conversion through synthesis gas, a mixture of CO and H₂. Recently, interest in direct methane conversion technologies with lower energy consumption has increased. Compared to research on methanol production via selective oxidation of methane, studies on the direct conversion of methane to acetic acid have been relatively scarce, but significant research progress has been made recently. This review classifies reports on the direct conversion of methane into acetic acid according to catalyst type (homogeneous vs. heterogeneous catalysts) and reaction conditions, and discusses the advantages and disadvantages of each approach. A relatively high yield of acetic acid can be achieved using CO as a carbonylating agent. However, the direct conversion of methane and CO₂ into acetic acid is more attractive from an environmental perspective. Recent advances in the field of electrocatalysis for this purpose are noteworthy. Other non-thermal catalytic methods, including photocatalysis, photoelectrocatalysis, and plasma processes, are also included. Based on the current state-of-the-art research trends in this field, future research directions are proposed. Full article

This study numerically investigates the effect of catalytic activity on the cold-start ignition and combustion characteristics of a propane-fueled U-bend catalytic micro-reactor. A reactive-wall approach is employed to model the catalyst coating, wherein catalytic activity is represented by the surface area factor. The results show that surface area factors between 0.425 and 3.4 exert a significant impact on ignition and combustion behavior, reducing the ignition temperature from 682 K to 521 K and decreasing the ignition delay time from 147 s to 52 s while increasing the HTR (heterogeneous reaction) contribution from 26.1% to 65.5%. Beyond a surface area factor of 3.4, performance improvements become marginal. The temporal analysis reveals that the catalytic reaction pathway dominates during the preheating stage, whereas the gas-phase reaction pathway gains prominence following ignition, eventually reaching a stable balance between the two pathways after approximately 10 s. These findings identify low catalytic activity as a sensitive operating regime and underscore the critical role of catalytic activity in optimizing ignition performance of catalytic micro-reactors. Full article