ChemCatChem最新文献

Platinum-based catalysts are highly effective for the oxygen reduction reaction (ORR), but their prohibitive cost and insufficient activity impede large-scale commercialization. Herein, we report a Pt@Fe-NC electrocatalyst synthesized by depositing uniform platinum nanoparticles onto an iron–nitrogen–carbon (Fe–NC) support via an ethylene glycol reduction method. The Fe–NC support, prepared from an iron (II)-1,10-phenanthroline complex precursor to ensure high iron utilization, modulates the electronic structure of the Pt nanoparticles, thereby enhancing both catalytic activity and stability. The optimized Pt@Fe-NC catalyst (13.54 wt% Pt) exhibits exceptional ORR performance in acidic media, with a half-wave potential of 0.852 V and notable stability. When integrated into a zinc-air battery, the catalyst delivered a high specific capacity of 652.66 mAh g_Zn⁻¹. Furthermore, a proton exchange membrane fuel cell (PEMFC) employing this catalyst achieved a high open-circuit voltage (OCV) of 0.964 V and a peak power density of 1.722 W cm⁻², outperforming most previously reported Pt-based catalysts. This study highlights a synergistic strategy between Pt nanoparticles and metal-nitrogen-carbon (M–N–C) supports to boost ORR performance, presenting a viable path toward advanced, cost-effective catalysts for energy conversion devices like PEMFCs and zinc-air batteries.

The oxidative fluorination of a ternary CZMg (Cu/ZnO/MgO) methanol catalyst resulted in a 5%–10% catalyst improvement within the first 3 to 4 days on a CO₂/3 H₂ stream reaching a stable and improved performance over 14 days on stream with respect to methanol productivity (at 40 bar, 250 °C, GHSV 19,800 NL kgcat⁻¹ h⁻¹). By contrast the powerful commercial (but more expensive) CZZ (Cu/ZnO/ZrO₂) and the industrially used CZA (Cu/ZnO/Al₂O₃) system optimized for CO/CO₂/H₂ streams lost 30% (CZA) / 12% (CZZ) of their initial methanol productivity and were surpassed in productivity by a fluorinated CZMg system within a few hours (CZZ) or after a few days on stream (CZA). This (fluorinated) CZMg catalyst system was characterized using methods including XPS, XAS, in situ pXRD, in situ EPR, and HRTEM. Hence, oxidative fluorination of the pristine CZMg system reduced the apparent activation energy for CO₂ hydrogenation E_A,app from 52 to 43 kJ mol⁻¹ (CZMg versus CZMg_F1250), removed the volcano shape of the methanol production under integral conversion in a stoichiometric (1 + x)H₂ / (CO_x)-variation stream (x = 1…2) and led to stable performance even with a CO₂-rich or pure CO₂-stream with stoichiometric amounts of H₂ present (at 40 bar, 250 °C, GHSV 19,800 NL kgcat⁻¹ h⁻¹). This long-term stability is most likely attributed to the formation of mixed oxo fluorides MgO_1-xF_2x during oxidative fluorination. Magnesium and fluoride are presumably incorporated into the ZnO_1-x overgrowths of the Cu nanoparticles, stabilize them against sintering and apparently prevent the catalyst from deactivation by water, thus acting as a structural support.

A one-step method was developed to synthesize highly ordered, primary amine–functionalized two-dimensional (2D) hexagonal mesoporous polymers, designed to enhance the density of catalytically active sites for CO₂ capture and subsequent hydrogenation to methanol. Incorporation of Pt nanoparticles generates an ordered bifunctional (base/metal) mesoporous system, enabling efficient CO₂ adsorption and optimal metal utilization for effective methanol synthesis from the captured CO₂ at the amine–metal interface. Compared with silica-based materials,^[1,2] this novel polymer achieves a fourfold increase in methanol yield while maintaining 100% selectivity under mild reaction conditions.

Electrocatalytic C–N coupling using gaseous pollutants NO and CO offers a promising alternative to conventional industrial urea synthesis. However, designing efficient electrocatalysts remains challenging due to the complexity of multi-step reactions, which yield diverse products. Herein, based on density functional theory (DFT) calculations, we explore Cu and p-block atoms (B, Al, and Ga) anchored on graphitic carbon nitride as novel heteronuclear double-atom catalysts (DACs) for urea synthesis from NO and CO. The reactants are stably adsorbed on the DACs, while strong d–p orbital hybridization facilitates effective activation and efficient C–N coupling. Among the candidates, CuB@g-C₃N₄ and CuGa@g-C₃N₄ exhibit particularly promising performance, with limiting potentials of −0.55 V and −0.36 V, respectively. Furthermore, these catalysts significantly suppress competing reactions, including the hydrogen evolution reaction (HER) and the formation of *NOH, *COH, and *CHO intermediates, ensuring high selectivity. Our work not only highlights highly efficient p-d DACs for electrocatalytic urea production but also provides a theoretical framework in catalyst design.

Conventional catalytic methodologies for the cycloaddition of CO₂ into epoxides predominantly rely on transition metal-based catalysts in conjunction with detrimental halide-containing cocatalysts. Thus, developing metal and halide-free catalysts that function under ambient conditions is highly desirable. The current research endeavours to synthesize a pyrimidine-based bifunctional organocatalyst via a facile one-step Schiff-base condensation reaction. The synthesized organocatalyst efficiently transforms a wide range of epoxides (35 different epoxides, including 6 challenging internal epoxides) into cyclic carbonates with a minimal catalyst loading of just 0.1 mol% under mild conditions (60 °C–100 °C, atmospheric CO₂ pressure) without solvents and cocatalysts. Comprehensive experimental investigations elucidate how the catalyst facilitates the reaction, emphasizing the intricate interplay of hydrogen (H) bonding, spatial arrangement, and catalyst-substrate interactions. The meticulous analysis, using advanced spectroscopic techniques and density functional theory (DFT) calculations, reveals that hydroxyl groups play a pivotal role in epoxide activation through H-bonding interactions, whereas the imine nitrogen facilitates CO₂ activation through the formation of a carbamate intermediate. These two interactions collectively accelerate the overall catalytic process. Furthermore, the catalyst exhibits remarkable recyclability over six consecutive catalytic cycles. Therefore, this study underscores the potential of rationally designed metal-free catalysts in advancing sustainable catalysis through carbon capture and utilization technologies.

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.