ChemCatChem最新文献

The preparation of powdery heterogeneous catalysts often involves the use of solvents, costly precursors, and thermal treatments in multi-step processes. Herein, we demonstrate the preparation of Ru nanoparticles on TiO₂ via spark ablation coupled with powder aerosolization, offering a clean and simple route with minimal waste generation and reduced pre- and post-synthesis processing. The as-prepared Ru/TiO₂ catalyst is readily active in CO₂ methanation reaction, achieving CH₄ formation rate of 0.21 mmolg_Ru⁻¹s⁻¹ and TOF of 0.11 s⁻¹ at 200 °C, outperforming the corresponding formulation prepared by wetness impregnation followed by calcination. The enhanced performance is attributed to a higher fraction of surface metallic Ru, as spark ablation under inert atmosphere typically yields metallic Ru nanoparticles. Additionally, Ru nanoparticles in the spark-made catalyst are well-distributed over both anatase and rutile TiO₂, driven by Brownian motion and van der Waals adhesion. By contrast, Ru/TiO₂-WI exhibits preferential Ru layer around rutile TiO₂ due to pre-existing RuO₂-rutile TiO₂ epitaxial interactions formed during calcination. This work highlights a sustainable approach for designing highly active low-temperature CO₂ methanation catalysts, with potential versatility for broader catalytic applications.

The Front Cover shows self-propelling catalytic micro-/nanobots (μ-Catbots) coated with Fe₃O₄ and Fe nanoparticles, which decompose H₂O₂ to O₂ and HCOOH to H₂, thus enabling real-time fuel cell powering. Magnetic control allows propulsion, bubble demixing, and easy retrieval. Image-based bubble analysis correlates with L–H kinetics, offering a novel approach for reaction rate evaluation and portable oxygen concentrators. More information can be found in the Research Article by D. Bandyopadhyay and co-workers (DOI: 10.1002/cctc.202500767).

Molybdenum carbide (MoC/Mo₂C), due to its unique noble-like metallic electronic structure, high conductivity, and abundant surface-active sites, exhibits promising catalytic performance for the hydrogen evolution reaction (HER). The directional and controllable synthesis of molybdenum carbide with specific phase composition is crucial for enhancing catalytic performance. This study employs a green and clean electrochemical method to achieve one-step controllable synthesis of a dual-phase MoC–Mo₂C in molten salt. The electrolytic mechanism analysis reveals that MoO₃ reacts with molten salt components to form soluble molybdate. Subsequently, CO₃²⁻ and MoO₄²⁻ as the electroactive ions are co-reduced, and then molybdenum carbide is in situ formatted at the cathode. By controlling the electrolysis temperature, the phase composition and morphology of molybdenum carbide are effectively regulated, yielding a feather-like dual-phase MoC–Mo₂C catalyst. In a 1.0 M KOH solution, the dual-phase MoC–Mo₂C catalyst exhibits a superior HER activity. The low overpotential is only 118 mV at a current density of 10 mA cm⁻² for HER. Furthermore, it exhibits excellent stability, with only a 34 mV overpotential increase at 10 mA cm⁻² after 30 h. This study provides a novel strategy for the clean and resource-efficient utilization of CO₂ to synthesize molybdenum carbide catalysts for high performance.

The Cover Feature shows a sustainable, solvent-free route for CO₂ utilization using a trimetallic NiO–CuO–ZnO catalyst, enabling room-temperature conversion of epichlorohydrin to chloropropene carbonate with 80% yield. This energy-efficient, scalable process avoids precious metals, supports green chemistry, and advances circular carbon economy pathways. More information can be found in the Research Article by J. Rajalakshmi, D. Rajagopal, and A. S. Kumar (DOI: 10.1002/cctc.202500934).

The electrochemical upgrading of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) represents a promising route for producing renewable monomers for biodegradable plastics. However, achieving high conversion and selectivity under industrially relevant conditions remains challenging due to sluggish kinetics and catalyst instability. Herein, we report the rational design of a Ru-doped CoFe Prussian blue analogue (Ru-CoFe PBA) catalyst directly grown on copper foam via a one-step hydrothermal process. Comprehensive structural and electronic characterizations reveal that Ru incorporation induces an electron-deficient state in Co and Fe centers, thereby facilitating the formation of hydroxide species and enhancing HMF adsorption. As a result, the Ru-CoFe PBA/CF electrode exhibits outstanding electrocatalytic activity for HMF oxidation, achieving 100% conversion, 98.9% FDCA selectivity, and 97% Faradaic efficiency in 1 M KOH with 100 mM HMF, along with excellent cycling stability. Furthermore, deployment in a multi-stage continuous flow reactor enables high HMF conversion and FDCA selectivity under a broad range of operational parameters, maintaining stable performance over 150 h of continuous operation. This work highlights the synergistic benefits of heteroatom engineering and flow reactor design, offering a scalable platform for efficient biomass electrooxidation to value-added chemicals.

Tetryliumylidene ions, stabilized by N-heterocyclic carbenes (NHCs), have emerged as promising main-group catalysts for the reduction of carbon dioxide (CO₂). Herein, we report the catalytic activity of aryl- and silyl-substituted silyliumylidenes (1 - 4) in the hydrosilylation of CO₂ with diphenylsilane at room temperature, using acetonitrile as solvent. With a low catalyst loading of 5 mol%, full conversion of diphenylsilane was achieved within a moderate reaction time, yielding a mixture of silylformate, bis(silyl)acetal, and silylated methanol. Mechanistic studies, supported by nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) calculations, suggest that the silyliumylidene ions act as precatalysts, forming sila-acylium ion intermediates that subsequently generate the catalytically active siloxy-silylene species. These findings highlight the potential of NHC-stabilized silyliumylidene ions as efficient and selective main-group catalysts for CO₂ hydrosilylation.

This study investigates the influence of the washing step on the physicochemical properties and catalytic performance of Ni–Al layered double hydroxide (LDH)-derived catalysts for CO₂ methanation. Catalysts were synthesized via co-precipitation and subjected to different washing levels, resulting in final conductivities ranging from 21000 µS/cm (0 W) to < 50 µS/cm (10 W). Nitrogen physisorption and X-ray diffraction analyses revealed that lower conductivity values led to increased surface area, reduced crystallite size, and improved structural homogeneity. H₂-TPR and CO₂-TPD profiles demonstrated that efficient washing enhances metal–support interactions and promotes the formation of stronger basic sites, both of which are critical for CO₂ activation. Catalytic tests showed that the 2 W sample washed to an intermediary level exhibited the highest CO₂ conversion at low temperatures (200–300 °C), whereas more thoroughly washed samples (10 W and 5 W) performed better at higher temperatures (>300 °C), likely due to their superior thermal stability and resistance to sintering. Post-reaction XRD and XPS characterization confirmed the structural integrity of the catalysts, with minimal crystallite growth. Furthermore, the 2 W catalyst maintained structural integrity, showed no coke formation, and experienced less than 3% mass loss in TPO after 51 h of reaction, confirming its excellent long-term stability. These findings highlight the importance of controlling washing conditions during synthesis to optimize the redox behavior, basicity, and overall catalytic efficiency of Ni–Al LDH-derived materials for CO₂ methanation.

A new laser vaporization (LAVA) method for the synthesis of CeO₂ nanoparticles, allowed the synthesis of support samples with widely variable surface area and particle sizes. The LAVA-synthesized CeO₂ nanoparticles exhibit a high degree of crystallinity, characterized by the absence of intracrystalline porosity, but high surface defectiveness and a well-developed interblock structure. Platinum deposition produces highly dispersed species, including isolated ions (single atoms Pt²⁺-SA), ion associates (2D-PtO_x rafts), and oxidized 3D-PtO_x clusters. The catalyst with the largest surface area and the smallest mean particle size of CeO₂ contains platinum mainly in the Pt²⁺-SA form, owing to its strongest chemical interaction with the surface of small-sized nanoparticles. This highly dispersed catalyst does not exhibit low-temperature activity in CO oxidation, since ignition of the reaction is only observed at T > 150 °C. The catalysts with reduced surface area contain both Pt²⁺-SA and 3D-PtO_x clusters located at extended surface defects and along interblock boundaries. The formation of 3D-PtO_x cluster species results in a significant enhancement of the catalytic activity. The most notable catalytic effect is observed for the lowest surface area catalysts, for which CO conversion shows low-temperature activity with the reaction ignition occurring at sub-zero temperatures.

Catalysis is a cornerstone of chemical manufacturing, with most industrial chemicals produced via catalytic processes. Heterogeneous catalysts are especially valued for their ability to operate under mild conditions, enhancing process efficiency and sustainability. Establishing structure-performance relationships requires comprehensive characterization of key physicochemical properties, such as structural, textural, reducibility, acid-base, and morphological characteristics, which directly influence catalytic activity, selectivity, and stability. This article presents a guide on the characterization of solid catalysts, providing practical insights for both novice and experienced researchers. It addresses morphological analysis through SEM and TEM, which provides essential information on particle size, shape, and distribution. Structural features, such as crystalline phase identification, crystal size, and crystallinity, are investigated using X-ray diffraction, while molecular structure is analyzed using Raman spectroscopy. Textural properties, such as surface area, pore volume, and pore size distribution, are discussed with gas physisorption. Reducibility is explored through temperature-programmed reduction, while acid-base properties are evaluated via NH₃-TPD, CO₂-TPD, and FT-IR spectra of pyridine to determine the amount, strength, and nature of acid and basic sites. Each section provides an overview of the theoretical principles behind these techniques, practical tips for accurate data acquisition, and case studies illustrating how to extract and interpret the most relevant information. Special emphasis is placed on ensuring that researchers can effectively extract and interpret data from each method correctly, helping to optimize catalyst characterization for the design and improvement of catalytic heterogeneous processes.

The renewable energy-driven electrocatalytic $$ reduction reaction ($$) offers a sustainable pathway to convert $$ into valuable $$ products, addressing both $$ emissions and energy demands. However, achieving efficient conversion to multi-carbon products remains a challenge due to the complexity of C–C coupling. In this study, we systematically screen monomer, dimer, and trimer configurations of transition metal-doped two-dimensional $$ ($$@$$) to identify optimal catalysts for enhanced $$ performance. Our findings reveal $$@$$ as a highly effective catalyst, capable of dual $$ activation, promoting C–C coupling, and selectively producing $$ products, while simultaneously suppressing hydrogen evolution (HER) and CO evolution. Notably, this research highlights alternative C–C coupling pathways beyond the conventional CO dimerization mechanism. These insights represent a significant advance in the design of efficient and selective catalysts, paving the way for sustainable $$ conversion into valuable multi-carbon products.