Catalysis Science & Technology最新文献

The electrochemical reduction of CO₂ (CO₂RR) offers a promising route for sustainable fuel and chemical production. This study compares the CO₂RR performance of hydrothermally synthesized carbon nanosphere-supported nickel hydroxide (Ni-C), copper hydroxide (Cu-C), and bimetallic nickel-copper hydroxide (NiCu-C) catalysts, investigating the influence of metal composition. Significant differences in product selectivity were observed: Cu-C primarily yielded C₂ products, whereas Ni-C and NiCu-C generated mixtures of H₂, CO, formate, and acetate, with minimal C₃ products. Faradaic efficiencies (FEs) for C₃ products (including propylene, propane, and n-propanol) were very low for Ni-C and NiCu-C (<0.3% combined). In comparison, Cu-C showed modest FEs (∼3-5%) primarily for n-propanol. X-ray photoelectron spectroscopy revealed partially oxidized nickel species (Ni ^δ+) in Ni-C and NiCu-C and predominantly Cu(i) species post-reaction, while scanning electron microscopy confirmed a distinct fibrous morphology for the Ni-containing catalysts. Control experiments with CO and acetate, and in situ Raman spectroscopy, suggest reaction pathways that differ from the typical Cu-catalyzed routes, potentially involving hydrogenated intermediates such as *CHO. This work provides a comparative analysis, highlighting how catalyst composition and associated electronic/structural properties influence the overall CO₂RR activity and selectivity pathways in Ni, Cu, and NiCu hydroxide systems, rather than achieving significant C₃ production.

Heterogeneous uranyl catalysts were constructed on Hf-MOLs via SBU/linker modifications. BTB-Hf-MOL-U (UO₃ nanoparticles) exhibits enhanced photocatalytic activity, while TPY-Hf-MOL-U (single-site) shows superior stability. This approach utilizing low-radioactivity depleted uranium addresses recyclability and contamination issues in homogeneous systems, enabling efficient C–H activation under blue light irradiation.

Improving the selectivity towards multi-carbon products for the electrochemical reduction reaction of CO₂ (CO₂RR) with Cu-based catalysts remains a significant topic of scientific interest. It is known that using a secondary metal can provide some control over selectivity, with the structure of the bimetallic catalysts playing an important role in product distribution. In this study, we synthesized Au/Cu₂O catalysts via a precipitation method followed by galvanic replacement using varying Au concentrations. This approach enabled a systematic investigation of the restructuring of Cu₂O phases decorated with highly dispersed Au, Au–Cu alloys, and Au clusters and their impact on the catalytic activity. Among the tested catalysts, the Cu₂O catalyst with highly dispersed Au exhibited the highest Faradaic efficiency towards ethylene and ethanol. In situ X-ray absorption spectroscopy (XAS) and quasi-in situ X-ray photoelectron spectroscopy (XPS) measurements revealed that the presence of Au influenced the reduction of Cu₂O, where the catalyst with highly dispersed Au displayed the highest fraction of cationic Cu species. Furthermore, in situ X-ray diffraction (XRD) was employed to study the structural evolution of crystalline phases of the catalysts during CO₂RR, which suggests that significant restructuring and redispersion of Au takes place. This work highlights the relevance of in situ studies to understand the dynamic interplay between the structure and the catalytic behavior during the reaction.

The dynamic behavior of catalysts under reaction conditions markedly influences their catalytic performance, highlighting the need to elucidate these effects for mechanistic understanding and catalyst design. In this study, by combining density functional theory calculations and ab initio molecular dynamics simulations, we identify pronounced upward displacements of surface La species on the La₂O₃(001) surface at typical reaction temperatures. These atomic motions activate a previously disfavored C–H bond cleavage pathway, which effectively suppresses product recombination and enhances catalytic efficiency by promoting rapid separation of the dissociation products. Our results underscore the significant role of lattice dynamics in altering reaction mechanisms on oxide catalysts and offer valuable insights for the development of high-performance catalytic systems.

Catalysis Science & Technology, Evgeny Pidko and Núria López would like to acknowledge Weixue Li for their contributions to the Digital Catalysis themed collection as a Guest Editor.

The development of regioselective and stereoselective catalytic methodologies marks a significant milestone in green chemistry. With the increasing need for sustainable practices in the chemical industry, these approaches are transforming the synthesis of complex chemical intermediates, including pharmaceuticals, agrochemicals, and functional materials. Catalytic methods make these reactions more selective to given substrates, which increases atom economy while lessening the environmental impact. The objective of this review is to analyze and discuss recent developments in catalysis with an emphasis on sustainable methodologies which include: transition metal catalysis, organocatalysis, photocatalysis, and electrocatalysis. The catalytic approaches not only offer cleaner and more efficient energy pathways for molecular transformations, but also support the use of hydrogen and bio-based feedstocks along with green solvents, adhering to eco-design principles. In academic and industrial settings, precision chemistry is achieved through regio- and stereoselective catalysis. The resulting discrete building blocks reduce the number of steps, resources, and waste necessary to produce the desired molecular structures. The inclusion of circular economy models and life-cycle assessment (LCA) methodologies has made these processes more appealing from a regulatory and industrial standpoint, driving a shift towards sustainable process innovations. Even so, the difficulties of catalyst deactivation, a narrow scope for reusability, limited substrate scope, and economic scalability barriers continue to impede industrial adoption across the field. To resolve these issues, the review suggests future strategies such as the creation of catalysts from earth-abundant metals, the formation of hybrid catalytic systems, AI and machine learning integration for catalyst development, and real-time dynamic optimization of processes through digital chemistry tools. The review also aims to motivate the design of catalytic systems that shift from environmentally irresponsible to sustainable, economically viable, and revolutionize the industry while bridging the gap between innovation and application by outlining achievements alongside existing problems, thus closing the gap between innovation and application.

The non-equilibrium conditions inherent in femtosecond laser ablation in liquids (LAL) offer a versatile platform for synthesizing metastable nanomaterials, yet predicting the structural evolution of complex oxides under rapid quenching remains a challenge. Here, we elucidate the divergent structural and functional outcomes of LAL applied to two related wide-bandgap niobium-based oxides: LiNbO₃ and Nb₂O₅. We find that the intrinsic crystallization kinetics of the materials dictate their response to laser-induced fragmentation and condensation. Nb₂O₅, a strong glass-former with complex polymorphism, is trapped in an amorphous state. In contrast, LiNbO₃ exhibits robust thermodynamic stability, favoring rapid nucleation and growth to form polycrystalline, albeit defect-rich, nanoparticles. These structural differences profoundly impact their electronic landscapes. Amorphization in Nb₂O₅ introduces a broad continuum of localized states that facilitate rapid charge recombination. Conversely, defect engineering in crystalline LiNbO₃ yields discrete mid-gap states that enhance visible-light absorption and prolong carrier lifetimes. Consequently, LiNbO₃ nanoparticles demonstrate sustained hydroxyl radical generation under visible irradiation, achieving a photocatalytic dye degradation rate threefold higher than their amorphous Nb₂O₅ counterparts and enabling 90% dye removal after 150 minutes at low catalyst loading. This investigation underscores the critical role of intrinsic crystallization kinetics in LAL synthesis and establishes defect-mediated crystallinity as a superior strategy over amorphization for activating wide-bandgap materials for solar-driven photocatalysis.

The addition of metal oxides as impurities to generate an intermediary energy band near the conduction or valence band to reduce the bandgap is the most distinctive approach to improve the photo-absorption characteristics of the material. Herein, we have reported the synthesis of nanohybrid bimetallic heterostructures by linking the interface of CeO₂ and CoO, which narrows the electronic band structure of CeO₂ from 2.85 eV to 1.5 eV and modulates the distribution of charges at the active sites. The resulting CeO₂/CoO hybrid support enhances the dispersion and stability of Pd NPs, resulting in lowering the activation energy (E_a) barrier of the coupling reaction, thereby significantly enhancing its catalytic efficacy. The E_a value of CeO₂/CoO/Pd (53.7 kJ mol⁻¹) is much lower compared to that of CeO₂/Pd (68.6 kJ mol⁻¹), with excellent catalytic activities (yield: 98%) and exhibiting long-term stability for 5 continuous cycles without any significant loss in activity. Overall, the CeO₂/CoO/Pd hybrid system effectively utilized the photothermal effect to facilitate an effective electron transfer, thereby enhancing the rate of the Suzuki–Miyaura coupling reaction. This study offers a feasible and encouraging prospect to use the heterostructured metal oxide-based catalytic system for efficient Suzuki–Miyaura cross-coupling reaction.

A useful strategy for the co-polymerization of ethylene and functional olefins relies on palladium catalysts, as palladium typically shows in contrast to many other metals a high tolerance to a variety of functional groups. Here we have prepared a set of palladium complexes containing a N,N-bidentate coordinating bis(pyridinium amidate) (bisPYA) ligand. Ligand variation included either para- or an ortho-pyridinium amidate arrangement, with the pyridinium site either sterically flexible or locked through a dimethyl substitution ortho to the amidate. Activation of these complexes with NaBArF in the presence of ethylene indicated that sterically locked ligand structures promoted ethylene conversion and produced polymeric materials. In particular, complex 4d with an ortho-pyridinium amidate bisPYA ligand was active with a production of 10.8 kg polyethylene per mol palladium at room temperature and 1 bar ethylene. Synthesis of the complexes in the presence of K₂CO₃ or Ag₂CO₃ afforded adducts in which the K⁺ or Ag⁺ ion is bound by the two oxygens of the bisamidate core, thus leading to trimetallic Pd⋯K⋯Pd complexes. Such adduct formation indicates a dual role of NaBArF in halide abstraction and metal sequestration, thus rationalizing the need for 2.5 equivalent of NaBArF per palladium complex for effective polymerization.

The interaction between Cu and Zr is crucial for the performance of Cu-based catalysts in CO₂ hydrogenation. This study compares a series of Cu–Zr catalysts with different Cu–Zr ratios prepared at two flow rates in a microreactor. The structural evolution of the catalysts was investigated using X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (CO₂-TPD). It is found that the enhanced mixing in the microreactor improves component dispersion in the Cu–Zr precipitates, leading to smaller CuO crystallite sizes in the calcined oxides and more Cu–Zr interfaces in the reduced catalysts, which thereby exhibit superior catalytic performance. Additionally, superior mixing in the coprecipitation enables the catalyst to achieve abundant Cu–Zr interfaces even at lower Zr content, whereas catalysts prepared under inferior mixing require higher Zr content to establish adequate Cu–Zr interfaces.