Catalytic Performance Research Articles

Stereocatalytic Effect of CeO2 for the Synthesis of trans‐3‐Penten‐2‐ol

AbstractThe transformation of biobased alkanediols over heterogeneous catalysts is a major object. Here, a series of catalysts were prepared for 2,4‐pentanediol dehydration to 3‐penten‐2‐ol. Ceria‐based catalysts had a unique property of showing high efficiency. More importantly, a stereocatalytic effect was observed for CeO2, yielding trans‐3‐penten‐2‐ol with a high selectivity. Raman, XPS, TPD, and TPR were carried out to clarify the catalyst structure, and the relationship between the catalyst structure and catalytic performance were studied. The amount of Lewis acid sites can hardly be correlated with the total concentrations of the oxygen vacancies. It was suggested that the geometry structure of the active sites played a crucial role in trans‐3‐penten‐2‐ol production. The oxygen vacancies originating from CeO2 consisted of active sites with a geometrical structure, which were different from those created by Pr doping CeO2. In addition, the Pr doping enhanced the oxygen migration, which resulted in side reactions, consequently, giving a lower selectivity to trans‐3‐penten‐2‐ol.

Dual‐Site NiO/Bi3O4Br Heterojunction Catalyst for High‐Efficiency CO2‐to‐CH4 Conversion

AbstractSolar light‐driven conversion of CO2 into chemicals with high calorific value is regarded as an upcoming carbon utilization technology for alleviating the energy crisis. This technique faces the challenge of low CO2 conversion and product yield due to charge recombination in the catalyst. In this paper, a dual‐reaction site heterojunction catalyst was designed and fabricated by combining NiO with Bi3O4Br nanosheets, for the separation of CO2 reduction and H2O oxidation semireactions, which effectively promoted electrons and holes separation. The resulting catalyst exhibited a high CH4 production rate (8.12 µmol/g) and selectivity (94.69%). Electron distribution and band structure were investigated to explain the satisfactory catalytic performance. In addition, combining the in‐situ DRIFTS results, a formic acid‐intermediated CO2‐to‐CH4 reaction pathway was proposed. This work aims to pave the way for CH4 production via CO2 photoreduction with high efficiency and selectivity.

Tuning structures and catalysis performance of two-dimensional covalent organic frameworks based on copper phthalocyanine building block and phenyl connector.

Based on the experimentally reported stable and conductive two-dimensional covalent organic frameworks with copper phthalocyanine (CuPc) as building block and cyan substituted phenyl as connector (CuCOF-CN) as an electrocatalyst for CO2 reduction reaction (RR), first principle calculations were performed on CuCOF-CN and its analog with the CN being replaced by H (CuCOF). Comparatively studied on the crystal structures, electronic properties, and CO2RR performance of the two catalysts found that CuCOF has reduced crystal unit size, more positive charge on Cu and CuPc segments, smaller band gap, and lower reaction barrier for CO2 RR than CuCOF-CN. CuCOF is proposed to be good potential electrocatalyst with good environment friendliness. The substituent effect and structure-property-performance relationship would help for designing and fabricating new electrocatalysts.

Effect of Sodium Terephthalate on the Electrocatalytic Performance of Active Self‐Supporting Nanoporous PdAg Catalysts

Direct‐methanol fuel cells (DMFCs) have become a hot research topic in the energy field due to their excellent energy conversion efficiency and environmental sustainability. Optimization of catalyst preparation strategy is the key to enhance the performance of DMFC. In this study, melt quenching is employed to synthesize Al–Pd–Ag precursor alloy ribbons, and self‐supported nanoporous Pd–Ag catalysts with high activity are successfully prepared by a precisely controlled dealloying process. The catalysts are characterized microstructurally and tested electrochemically, and their performance is compared with samples without sodium terephthalate addition and with commercial Pt/C and Pd/C catalysts. In the results, it is shown that the maximum peak current density of methanol electrocatalytic oxidation is significantly enhanced to 1451.16 mA mg−1 with the addition of 15 mM sodium terephthalate, which is about 6.6 times higher than that of the unadded samples, and the catalytic performance is improved by a factor of 7.7 and 12.0, respectively, compared to those of commercial Pt/C and Pd/C. This remarkable performance enhancement is attributed to the innovative dealloying method, which not only refines the catalyst structure but also achieves a significant increase in catalytic performance through the assistance of active self‐supporting nanoporous structures and interfacial synergistic effects between palladium and silver.

Lattice Strain Regulated by Hetero/Homo Atom Interface Merging on NiMo Nanocluster for High-Performance Hydrogen Production.

Lattice strain engineering represents a cutting-edge approach capable of delivering enhanced performance across various applications. The lattice strain can affect the performance of electrochemical catalysts by changing the binding energy between the surface-active sites and intermediates. In this work, lattice strain is regulated through a homo/heterogeneous atomic interface merging. The strong lattice strain and electronic interactions between Ni and Mo facilitated the reaction kinetic of HER. The prepared NiMo@SSM exhibits excellent HER catalytic performance with 70 mV overpotential at the current density of 10 mA cm-2 and long-term stability. The method of controlling lattice strain through hetero/homo atom interface merging provides a new strategy for designing high-performance alkaline HER electrocatalysts.

Densely populated single‐atom catalysts for boosting hydrogen generation from formic acid

AbstractThe single‐atom M‐N‐C (M typically being Co or Fe) is a prominent material with exceptional reactivity in areas of catalysis for sustainable energy. However, the formation of metal nanoparticles in M‐N‐C materials is coupled with high‐temperature calcination conditions, limiting the density of M‐Nx active sites and thus restricting the catalytic performance of such catalysts. Herein, we describe an effective decoupling strategy to construct high‐density M‐Nx active sites by generating polyfurfuryl alcohol in the MOF precursor, effectively preventing the formation of metal nanoparticles even with up to 6.377% cobalt loading. This catalyst showed a high H2 production rate of 778 mL gCat−1 h−1 when used in the dehydrogenation reaction of formic acid. In addition to the high density of the active site, a curved carbon surface in the structure is also thought to be the reason for the high performance of the catalyst.

Revealing Dynamics and Competitive Mechanism of Gas-Induced Surface Segregation of PdFe0.08 Dilute Alloy by Multi-Dimensional Imaging.

The restructuring of dilute alloys under gas environments has shown a great impact on their catalytic performance due to intriguing structural sensitivity, but the structural dynamics and underlying mechanism remains elusive. Herein, we directly resolved the distinct dynamic behaviors of PdFe0.08 dilute alloys under CO or O2 environment by multidimensional imaging. The stronger binding of gaseous CO with Fe atoms stimulates Fe segregation out of the PdFe0.08, resulting in 3D growth of Fe islands, whereas the dissociative adsorption of O2 results in 2D layer-by-layer growth of segregated FeO as encapsulation overlayers that bind strongly with the Pd surface underneath. Such varied structures remarkably tune the catalytic activity for CO oxidation, showing a considerably high activity for a CO-treated sample. Our results reveal the competitive mechanism between adsorbate-metal and metal-metal interaction for gas-induced surface segregation, which should be highly considered for the rational design of dilute alloys with dynamically tuned structure and reactivity.

Tailoring of Novel Ru (III) and Cr (III) Salen Complexes as Catalysts for a Sustainable and Green Synthesis of Dihydro‐tetrazolo [1,5‐a] thiazolo [4,5‐d] pyrimidin‐6‐yl morpholine: Experimental and Theoretical Approaches

ABSTRACTTwo novel Cr (III) and Ru (III) salen complexes based on {3,4‐Bis‐[(5‐chloro‐2‐hydroxy‐benzylidene)‐amino]‐phenyl}‐phenyl‐methanone ligand (CSAB) were synthesized. The complexes were characterized using various spectral and analytical methods. The catalytic performance of the CSAB complexes was investigated via a four‐component condensation reaction involving aromatic aldehydes, rhodamine, morpholine, and 5‐aminotetrazole under mild, environmentally friendly conditions. Different Lewis acids, bases, ionic liquid catalysts, solvents, and catalyst amounts were assessed to optimize the reaction parameters. Both catalyst systems demonstrated robust catalytic activity under strictly managed conditions, with the heterogeneous catalyst CSAB‐Ru showing superior efficacy compared to the homogeneous CSAB‐Cr catalyst. The study confirmed the catalytic capabilities of both complexes and evaluated their recyclability and reusability. The heterogeneous catalyst (CSAB‐Ru) could be reused seven times, whereas the homogeneous catalyst (CSAB‐Cr) could be recycled four times. Both complexes demonstrated strong catalytic activity and selectivity, resulting in high product yields. The study provides insights into the synthetic applications of novel CSAB complexes, highlighting their potential in organic transformations. It emphasizes their ease of use, safety, stability, component availability, quick reaction times, and high yields, making them promising for future industrial applications.

Co-infiltration and dynamic formation of Pd3ZnCx intermetallic carbide by syngas boosting selective hydrogenation of acetylene.

Transition metal carbide shows excellent performance in selective hydrogenation of acetylene, however, the carburization of Pd-based intermetallic compounds remains infeasible. Here we report the successful synthesis of an unprecedented Pd3ZnCx intermetallic carbide, via co-infiltration of zinc and carbon in one-step carburization by syngas. Utilizing state-of-the-art in situ characterizations and theoretical calculation, we unveil the dynamic evolution of Pd3ZnCx during carburization, forming a Pd3Zn like cubic phase carbide structure. A unique transitional state (Pdt) with low content of Zn/C co-infiltration is clearly identified facilitating phase transition and sustain incorporation of carbon and zinc at elevated temperatures. The Pd3ZnCx carbide shows by far the best catalytic performance in the selective hydrogenation of acetylene with a high selectivity (>90%) even at a high H2/C2H2 ratio. Our results therefore provide a co-infiltration strategy and dynamic insights for the one-step synthesis of Pd based intermetallic carbides, towards high-performance intermetallic compound for selective hydrogenation of acetylene.

Transition Metals Doped into g-C3N4 via N,O Coordination as Efficient Electrocatalysts for the Carbon Dioxide Reduction Reaction.

The electrochemical carbon dioxide reduction reaction (CO2RR) is a potential and efficient method that can directly convert CO2 into high-value-added chemicals under mild conditions. Owing to the exceptionally high activation barriers of CO2, catalysts play a pivotal role in CO2RR. In this study, the transition metal (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) is doped into g-C3N4 with a unique N,O-coordination environment, namely, TM-N1O2/g-C3N4. Herein, the catalytic performance and reaction mechanism for the CO2RR on TM-N1O2/g-C3N4 are systematically investigated by density functional theory methods. Especially, through the calculation of ΔG*H and ΔG*COOH/ΔG*OCHO, the catalysts with preference for the CO2RR over the hydrogen evolution reaction (HER) are selected for further study. Furthermore, Gibbs free energy computation results of each elementary step for the CO2RR on these catalysts indicate that Ti-N1O2/g-C3N4 has significant catalytic activity and selectivity for reducing CO2 to methanol (CH3OH) with the limiting potential (UL) of -0.55 V. Finally, through frontier molecular orbital theory and charge transfer analyses, the introduction of the O atoms illustrates that it is instrumental in regulating the electron distribution of the catalytic active site, thereby improving the catalytic performance. This work provides insight into the design of single-atom catalysts with unique coordination structures for the CO2RR.

Theoretical Study on Pt1/CeO2 Single Atom Catalysts for CO Oxidation

Understanding the influence of structural configurations on catalytic performance is crucial for optimizing atom‐efficient single‐atom catalysts (SACs). In this study, we conducted a density functional theory (DFT) investigation of single Pt atoms positioned at step‐edges and within a solid solution on the CeO2(111) surface. We compared these configurations in terms of thermodynamic stability, electronic properties, and further potential energy surfaces for CO oxidation. Stability studies revealed that the solid solution catalyst exhibits greater stability compared to the step‐edge catalyst. Additionally, the Pt in the solid solution catalyst can effectively activate lattice oxygen atoms, making the catalyst more conducive to the formation of oxygen vacancies. The CO oxidation process was analyzed using the Mars‐van Krevelen mechanism, revealing that the solid solution catalyst possesses a more moderate CO adsorption energy. This, coupled with its lower oxygen vacancy formation energy, leads to reduced energy barriers throughout the CO oxidation cycle. Our findings highlight the strong dependence of catalytic activity on the specific configuration of Pt atoms within the CeO2 matrix, with the solid solution model demonstrating superior catalytic efficiency compared to the step‐edge‐supported Pt catalysts.

Regulating the Local Spin States in Spinel Oxides to Promote the Activity of Li-CO2 Batteries.

Due to the high energy barrier, slow reaction kinetics, and complex reaction environments of Li-CO2 batteries, the development of durable and efficient catalysts is essential. Transition metal oxides are promising for their availability, stability, and 3d electronic features, with spin states playing an important role in CO2 activation. In this study, the local spin states are regulated by incorporating Ni into Co3O4 and its impact on activity in Li-CO2 batteries is explored. The results show that Ni atoms with high spin states in Ni0.1Co2.9O4 facilitate electron transfer from the catalyst to the unoccupied orbitals of CO2, providing sufficient active sites for the nucleation and growth of small Li2CO3 crystals. These small crystals have a low decomposition barrier, leading to improved battery efficiency. Therefore, Ni0.1Co2.9O4 shows superior catalytic performance with an overpotential of 0.72V and an energy efficiency of ≈70% after 500h. This work provides insights into the relationship between spin states and CO2 reactions, highlighting a promising avenue for developing high-performance metal-CO2 batteries.

Optimization of hydrogen production via electrocatalysis using NiCoMo-modified electrodes: An RSM approach

ABSTRACT The depletion of fossil fuels and the environmental impact of their combustion have increased the demand for sustainable energy alternatives, with hydrogen appearing as an appropriate option due to its clean energy potential. This study focuses on developing a laboratory-scale alkaline electrolysis system for hydrogen production. Platinum, known for its high catalytic activity and durability, was employed as the anode, while graphite was selected as the cathode for its cost-effectiveness. To enhance catalytic performance, the graphite electrodes were modified with nickel-cobalt-molybdenum (NiCoMo) using a galvanostatic method. The electrode voltage and molarity were chosen as independent variables to evaluate their effect on hydrogen production. Using the Design-Expert software, the optimal conditions were identified at 3 V and 1.5 mol/l, yielding 10.67 ml of hydrogen. The coefficient of determination (R2) values 98.81% for R2, 97.96% for adjusted R2, and 91.63% for predicted R2 indicate suitable model accuracy. The error margin between experimental and optimized results was only 1.7%, confirming the reliability of the method. This study highlights the potential of NiCoMo-modified electrodes to enhance hydrogen production efficiency. Future research could explore scaling up the system and integrating it with renewable energy sources, positioning this method as a viable pathway toward sustainable hydrogen production.

Programmed Charge Transfer in Conjugated Polymers with Pendant Benzothiadiazole Acceptor for Simultaneous Photocatalytic H2O2 Production and Organic Synthesis.

While being important candidate for heterogeneous photocatalyst, conjugated polymer typically exhibits random charge transfers between the alternating donor and acceptor units, which severely limits its catalytic efficiency. Herein, inspired by natural photosystem, the concept of guiding the charge migration to specific reaction sites is employed to significantly boost photocatalytic performance of linear conjugated polymers (LCPs) with pendant functional groups via creating programmed charge-transfer channels from the backbone to its pendant moiety. The pendant benzothiadiazole, as revealed in both in situ X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations, can act as electron "reservoir" that aggregates electrons at the active sites. Moreover, the presence of charge-transfer channels, evidenced by transient absorption spectroscopy (TAS), accelerates the electron transfer, preventing the recombination of electrons and holes. As a result, in this elaborately-designed architecture, the photogenerated electron can move smoothly towards the reduction sites, facilitating the reduction of O2 into H2O2, while remaining holes are directed to oxidation centers, simultaneously oxidizing furfuryl alcohol to furoic acid. The optimized photocatalyst LCP-BT demonstrates a competitive catalytic performance with H2O2 productivity of 868.3 μmol L-1 h-1 (9.8 times higher than conventional random charge-transfer polymer LCP-1) and furfuryl alcohol conversion over 95% after 6 h.

Controlling Metal-Support Interactions to Engineer Highly Active and Stable Catalysts for COx Hydrogenation.

This perspective focuses on the modulation of metal-support interaction (MSI) in catalysts for COx hydrogenation, highlighting their profound impact on catalytic performance. Firstly, it outlines different strategies, including the use of highly reducible oxides and moderate reduction treatments, which induce the classical strong metal-support interaction (SMSI) effect and the electronic metal-support interaction (EMSI) effect. Morphology engineering and crystalline phase manipulation of oxides presented as effective methods to control EMSI are also discussed. The discrimination of SMSI and EMSI can be achieved using oxides with low encapsulation tendencies, such as ZrO2, which supports electronic modifications without or minimizing the overgrowth issues, optimizing the catalytic performance for methanation. Then, the synergy between Cu and ZnO in methanol synthesis, enhanced by SMSI, is emphasized inside. Optimizing support oxides to control oxygen vacancies enhances the catalytic performance of CO2 hydrogenation to methanol. Perspectives for the future research on the fundamental understanding of structure-MSI-performance relationship for catalyst design is discussed.

Advanced Preparation Methods and Biomedical Applications of Single-Atom Nanozymes.

Metal nanoparticles with inherent defects can harness biomolecules to catalyze reactions within living organisms, thereby accelerating the advancement of multifunctional diagnostic and therapeutic technologies. In the quest for superior catalytic efficiency and selectivity, atomically dispersed single-atom nanozymes (SANzymes) have garnered significant interest recently. This review concentrates on the development of SANzymes, addressing potential challenges such as fabrication strategies, surface engineering, and structural characteristics. Notably, we elucidate the catalytic mechanisms behind some key reactions to facilitate the biomedical application of SANzymes. The diverse biomedical uses of SANzymes including in cancer therapy, wound disinfection, biosensing, and oxidative stress cytoprotection are comprehensively summarized, revealing the link between material structure and catalytic performance. Lastly, we explore the future prospects of SANzymes in biomedical fields.

Spinel-Based Catalysts That Enable Catalytic Oxidation of Volatile Organic Compounds.

Volatile organic compounds (VOCs) have caused serious harm to human health and ecological environment, and have received much attention in recent years. Despite the successful applications of catalytic combustion of VOCs as the core technology of VOCs removal in industry, the development of efficient catalysts that can mineralize VOCs into nontoxic CO2 and H2O at low temperatures remains a great challenge. Recent studies show that spinel-based materials as efficient catalysts were extensively used in the catalytic oxidation VOCs field due to their synergistic effect, manifold compositions, and electron configurations. However, most of the pollutants are complex, consisting of multiple VOCs, water vapor, CO2, SO2 and other substances, which presents a significant challenge in constructing highly active and stable catalysts. To meet the future demand for efficient catalysts capable of removing various types of VOCs, it is urgent to rationally design and scientifically prepare spinel catalysts based on existing knowledge. This work reviews the research and development of various spinel catalysts with an emphasis on their catalytic performance in VOCs oxidation. The catalytic performance of spinel-based catalysts for different sorts of VOCs was summarized and compared. Moreover, the effects of the reaction conditions on the catalytic performance of spinel-based catalysts were examined to accommodate complicated operating conditions. Subsequently, the regulation of spinel oxides in structure and defect was coherently reviewed to guide the development and design of efficient catalysts. Especially, the research techniques for the reaction mechanism over spinel catalysts were displayed to better deepen the understanding of catalytic oxidation of VOCs. Finally, the current development and challenges were proposed and put forward for future research. This review provided a systematic understanding of the VOCs oxidation over spinel-based catalysts and offered guidance for the development of high-performance catalysts for VOCs elimination.

Morphology‐Dependent Catalytic Activity of ZnFe2O4 Spinel Toward Light Olefins from Fischer–Tropsch Synthesis

AbstractThe shape‐defined ZnFe2O4 spinel with cubic and octahedral morphology was hydrothermally synthesized, respectively, and used as catalyst precursor for Fischer–Tropsch synthesis (FTS). The structure of ZnFe2O4 spinel was changed to ZnO and Fe5C2 (Fe5C2/ZnO) after reduction and carbonization. Interestingly, ZnFe2O4 with cubic morphology exhibited much higher catalytic activity and selectivity toward low‐carbon olefins (C2–C4) than the octahedral one under identical conditions, and the latter tended to produce the saturated alkanes. The primary properties of ZnFe2O4 materials before and after reduction were systematically studied through a series of characteristic technologies to reveal the difference in catalytic performance between the two ZnFe2O4 spinels with different morphologies.

Rapid Degradation of Dye Effluents with A SnS Catalyst: A Sustainable Approach Using Natural Light Under Ambient Conditions.

Dye degradation presents a persistent challenge in addressing water pollution. While several methods, including adsorption, biodegradation, and advanced oxidation processes, have been extensively explored, photocatalysis remains one of the most effective techniques. Conventional photocatalytic dye degradation processes often rely on expensive light sources and are time-intensive. Herein, we synthesized a SnS catalyst by the solvated metal atom dispersion (SMAD) method, using Sn foil and sulfur powder. The catalyst exhibited remarkable performance, achieving complete degradation of methylene blue within 2 minutes under ambient room light, without the need for any external light source. Similar degradation efficiency was achieved for methyl orange. To evaluate the role of light for the degradation, control experiments were conducted in the dark using methylene blue as a model dye. Although the degradation rate was slightly reduced, the catalyst still facilitated dye degradation in the absence of light. Additionally, the catalytic performance was tested with four other dyes under natural light, all of which yielded promising results, demonstrating the versatility and effectiveness of the SnS catalyst in dye degradation. This work highlights the potential of the SnS catalyst for efficient and rapid dye degradation under both light and dark conditions, offering an energy-efficient solution for wastewater treatment.

Recent Advances in NO Reduction with NH3 and CO Over Cu-Ce Bimetallic and Derived Catalysts

Sintering flue gas contains significant amounts of harmful gases, such as carbon monoxide and nitrogen oxides (NOx), which pose severe threats to the ecological environment and human health. Selective catalytic reduction (SCR) technology is widely employed for the removal of nitrogen oxides, with copper-cerium-based bimetallic catalysts and their derivatives demonstrating excellent catalytic efficiency in SCR reactions, primarily due to the significant synergistic effect between copper and cerium. This paper summarizes the main factors affecting the catalytic performance of Cu-Ce-based bimetallic catalysts and their derivatives in the selective catalytic reduction of ammonia and carbon monoxide. Key considerations include various preparation methods, doping of active components, and the effects of loading catalysts on different supports. This paper also analyzes the influence of surface oxygen vacancies, redox capacity, acidity, and specific surface area on catalytic performance. Additionally, the anti-poisoning performance and reaction mechanisms of the catalysts are discussed. Finally, the paper proposes strategies for designing high-activity and high-stability catalysts, considering the development prospects and challenges of Cu-Ce-based bimetallic catalysts and their derivatives, with the aim of providing theoretical guidance for optimizing Cu-Ce-based catalysts and promoting their industrial applications.