Multifunctional Catalysts Research Articles

MIL-101(Fe)-derivatized cathode as an efficient oxygen electrocatalyst for rechargeable Zn-air battery

The exploration of multifunctional electrocatalysts with cost-effective and high kinetic activity for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is crucial for the development of advanced energy conversion and storage equipment. Herein, a novel hierarchical mesoporous/macropores MIL-101(Fe) derivative carbon catalyst material was prepared by a simple molten ZnCl2-assisted synthesis route. Specifically, 1H-benzotriazole (BTA) organic ligands were intentionally introduced as nitrogen sources in order to induce the formation of charge-rich regions through an electronegative nitrogen doping control strategy, and most importantly, the lone pair electron-rich nature of element N could facilitate the separation and anchoring of iron species enchanted the utilization rate of active sites. Because of these properties, the as-prepared catalyst (denoted as FeSACs/NxC) possesses unrivalled bifunction electrocatalytic activity and durability for the ORR and OER. The FeSACs/N1.25C as working electrode exhibits a quite satisfactory electrochemical performance for the ORR (half-wave potential of 0.82 V) and OER (a small overpotential of 302 mV at 10 mA cm−2) in the classic three-electrode configuration. Moreover, the FeSACs/N1.25C-based air cathode imparts encouraging performance in a rechargeable Zn–air battery prototype with an open-circuit voltage of 1.45 V, a specific capacity of 792.16 mAh g−1, an energy density of 871.38 Wh kg−1, and excellent stability for 120 h. This work has opened the way for the development of low-cost, fast kinetic and stable non-noble metal multifunctional catalysts.

Experimental and theoretical investigation of phenylpyridine-based hypercrosslinked polymers for atmospheric CO2 adsorption and fixation under solvent-/metal-free conditions

Several phenylpyridine- and phenyl-based hypercrosslinked polymers (HCPs) were prepared via a one-step Friedel-Crafts polymerization and used as catalysts for the cycloaddition reaction between atmospheric CO2 and epoxides to produce cyclic carbonates. The structural characteristics and catalytic activity of different HCP catalysts were compared, while the recycling performance and universality to various substituted epoxides were investigated. The as-prepared catalysts exhibited regular pore structure and high specific surface area (1133 m2/g). Under the synergistic effect of tetrabutylammonium iodide (TBAI), the optimized TPA-HCP-Py efficiently converted atmospheric CO2 into cyclic carbonates with good to excellent product yields. Furthermore, the TPA-HCP-Py catalyst was easy to recover, and no significant changes were observed after reusing for five times, which demonstrated its excellent recycling performance. The interactions between different active sites and reactants in the TPA-HCP-Py/TBAI catalytic system were investigated by DFT calculation, revealing the catalytic reaction mechanism and providing valuable guidance for developing new multifunctional catalysts.

Heterogeneous CuS QDs/BiVO4@Y2O2S Nanoreactor for Monitorable Photocatalysis.

Exploration of multifunctional integrated catalysts is of great significance for photocatalysis toward practical application. Herein, a 1D confined nanoreactor with a heterogeneous core-shell structure is designed for synergies of efficient catalysis and temperature monitoring by custom encapsulation of Z-scheme heterojunction CuS quantum dots/BiVO4 (CuS QDs/BiVO4) and Y2O2S-Er, Yb. The dispersed active sites created by the QDs with high surface energy improve the mass transfer efficiency, and the efficient electron transport channels at the heterogeneous interface extend the carrier lifetime, which endows the nanoreactor with excellent catalytic performance. Meanwhile, real-time temperature monitoring is realized based on the thermally coupled levels 2H11/2/4S3/2→4I15/2 of Er3+ using fluorescence intensity ratio, which enables the monitorable photocatalysis. Furthermore, the nanoreactor with a multidimensional structure increases effective intermolecular collisions to facilitate the catalytic process by restricting the reaction within distinct enclosed spaces and circumvents potential unknown interaction effects. The design of multi-space nanoconfined reactors opens up a new avenue to modulate catalyst function, providing a unique perspective for photocatalytic applications in the mineralization of organic pollutants, hydrogen production, and nitrogen fixation.

Fe-single-atom catalysts boosting electrochemiluminescence via bipolar electrode integrated with its peroxidase-like activity for bioanalysis

Multifunctional single-atom catalysts (SACs) have been extensively investigated as outstanding signal amplifiers in bioanalysis field. Herein, a type of Fe single-atom catalysts with Fe-nitrogen coordination sites in nitrogen-doped carbon (Fe–N/C SACs) was synthesized and demonstrated to possess both catalase and peroxidase-like activity. Utilizing Fe–N/C SACs as dual signal amplifier, an efficient bipolar electrode (BPE)-based electrochemiluminescence (ECL) immunoassay was presented for determination of prostate-specific antigen (PSA). The cathode pole of the BPE-ECL platform modified with Fe–N/C SACs is served as the sensing side and luminol at the anode as signal output side. Fe–N/C SACs could catalyze decomposition of H2O2 via their high catalase-like activity and then increase the Faraday current, which can boost the ECL of luminol due to the electroneutrality in a closed BPE system. Meanwhile, in the presence of the target, glucose oxidase (GOx)-Au NPs-Ab2 was introduced through specific immunoreaction, which catalyzes the formation of H2O2. Subsequently, Fe–N/C SACs with peroxidase-like activity catalyze the reaction of H2O2 and 4-chloro-1-naphthol (4-CN) to generate insoluble precipitates, which hinders electron transfer and then inhibits the ECL at the anode. Thus, dual signal amplification of Fe–N/C SACs was achieved by increasing the initial ECL and inhibiting the ECL in the presence of target. The assay exhibits sensitive detection of PSA linearly from 1.0 pg/mL to 100 ng/mL with a detection limit of 0.62 pg/mL. The work demonstrated a new ECL enhancement strategy of SACs via BPE system and expands the application of SACs in bioanalysis field.

Value‐Added Cascade Synthesis Mediated by Paired‐Electrolysis Using an Ultrathin Microenvironment‐Inbuilt Metalized Covalent Organic Framework Heterojunction

AbstractEnergy‐saving and value‐added management in advanced catalysis is highly desirable but is challenged by the limitations of multifunctional catalysts and catalytic modules. Herein, an azo‐linked phthalocyanine‐porphyrin covalent organic framework (COF) with the ultrathin layered nanostructure grown on carbon nanotubes (NiPc‐azo‐H2Pp@CNTs) has been designed and synthesized, which can serve as a highly active and stable bifunctional heterojunction electrocatalyst for selective paired‐electrosynthesis through coupling anodic iodide oxidation reaction and cathodic CO2 conversion. Particularly, the inbuilt local microenvironment conferred by the dihydroporphyrin moieties in COF can act as a proton reservoir to promote the proton relay at the heterojunction interface during the electrocatalytic process. Moreover, through the cascade construction of dual electrocatalytic/organocatalytic modules, the cathode‐generated CO can be further converted to dimethyl carbonate with a yield of 6.21 mmol L−1 h−1, while the anode‐produced iodine can be derived into iodoform on the hundred‐milligram scale. It is worth noting that the value‐added cascade synthesis mediated by paired‐electrolysis using the distinctive and high‐powered electrocatalysts will help advance the sustainable development of industrial intelligent manufacturing.

Cobalt and chlorine co-doped Bi5O7I catalysts for LED-induced photocatalytic or PMS-activation antibiotics degradation

Multifunctional semiconductor catalysts can meet the urgent needs for the removal of antibiotic pollutants in water. Bifunctional catalysts, cobalt and chlorine co-doped Bi5O7I (signed as Co-BIC) catalysts, were purposefully designed through a two-step aqueous strategy. The preformed Bi5O7I precursor provided one-dimensional structure and Bi-rich character for the construction of Co-BIC catalysts. Co and Cl co-doping in Bi5O7I crystals can form a doping energy level and improve the internal electric field, which led to enlarged visible-light absorption and charge separation efficiency during the photocatalytic reaction process. These advantages made Co-BIC crystals exhibit good photocatalytic activities for the removal of antibiotic levofloxacin (LEV), ciprofloxacin (CIP) and tetracycline (TC) under visible LED (100 W) light irradiation. The degradation efficiency of LEV, CIP and TC over the typical Co-BIC-60 catalyst can reach more than 80 % under 60 min of LED irradiation. In the system of Co-BIC activated peroxymonosulfate (PMS), ∼ 90 % of LEV, CIP and TC degraded within 20 min over 20 mg of Co-BIC-60 catalyst. The mechanism of photocatalytic degradation and PMS oxidation degradation over Co-BIC catalysts was proposed on band structures of Co-BIC catalysts and the active species in the capture experiments. This work could provide new ideas for the preparation of bismuth oxyhalide catalysts coupled with transition metal elements.

Regulating the P-band center of SnS2-SnO2 heterostructure to boost the redox kinetics for high-performance lithium-sulfur battery

Lithium-sulfur batteries (LSBs) are considered a strong contender for the new-generation secondary energy storage system due to their high capacity and energy density. However, the sluggish reaction kinetics and the shuttle effect of lithium polysulfides (LPSs) severely hinder the cycle stability. The robust design of both the separator and cathode exhibit an effective role in restricting the shuttle effect and accelerating redox kinetics through the LPSs trapping and catalyzing effect. In this paper, a CNT-modified tin sulfide and tin oxide (SnS2-SnO2-CNTs) heterostructure was constructed as a multifunctional catalyst to modify both the separator and cathode to achieve high-performance LSBs. The formation of SnS2-SnO2 heterostructure promotes the movement of the P band center of the tin atom to the Fermi level, which realizes the association process of adsorption, capture, and conversion of LPSs, thus effectively suppressing the shuttle effect. The SnS2-SnO2 heterogeneous interface can also reduce the deposition barrier of Li2S, thus greatly promoting the redox kinetics. Together with the improved electron transfer, the resulting LSBs with the robust electrode and separator exhibit superior electrochemical performance with a high initial capacity of 930.2 mAh g−1 at 1 C with a high sulfur loading of 4.3 mg cm−2 and a remarkable capacity of up to 580.3 mAh g−1 at an ultrahigh rate of 7.4 C.

Modified nano magnetic Fe2O3-MgO as a high active multifunctional heterogeneous catalyst for environmentally beneficial carbon–carbon synthesis

In this study, novel nanomagnetic catalysts, namely Fe2O3-MgO@choline formate (Ch. F.) and Fe2O3-MgO@choline cyanide (Ch. CN), were synthesized through immobilizing choline-based ion liquids to magnetic support via a simple and cost-effective methodology. FT-IR, TGA, FE-SEM, VSM, EDS, BET, and XRD techniques were employed to assess and characterize these organic–inorganic compounds. Following the successful preparation of nanoparticles, the catalysts were utilized in Knoevenagel and benzoin condensations. Fe2O3-MgO@Ch.F. exhibited exceptional activity in Knoevenagel condensation under solvent-free conditions at room temperature, achieving high yields (91–98%) in a short timeframe. Similarly, Fe2O3-MgO@Ch.CN demonstrated remarkable activity in benzoin condensation under environmentally friendly solvent conditions, yielding higher isolated yields (76–88%). Furthermore, these magnetically recyclable multifunctional catalysts displayed the ability to be reused up to five times without a significant loss in efficiency. Additionally, the heterogeneity of this nanocatalyst was investigated using the hot filtration technique. The findings indicated that the reaction primarily occurs via a heterogeneous pathway.

MoC‐MoSe2 Heterostructures as Multifunctional Catalyst Toward Promoting the Stepwise Polysulfide Conversion for Lithium‐Sulfur Batteries

AbstractCatalyzing polysulfides conversion for lithium‐sulfur batteries is an efficient strategy to overcome the sluggish kinetics of polysulfides conversion as well as its serious shuttling effect. Due to the multistep and complicated phase transformation of sulfur species, the monofunctional catalyst can hardly promote the overall polysulfides redox process. Herein, a molybdenum‐based heterostructure is proposed, that facilitates the entire reduction process by tandemly catalyzing liquid‐liquid conversion and liquid‐solid conversion. It is uncovered that the MoC physiochemically immobilizes the soluble long‐chain polysulfide and accelerates the conversion between S8 to Li2S4 through adsorbing Li2S8 and extending its S─S bond distance. Then, the kinetics of Li2S precipitation is enhanced by facilitating the migration of Li2S4 from MoC to MoSe2. This is driven by the internal electric field at the heterogeneous interface and the low diffusion energy barrier on MoSe2 for Li2S4. Moreover, MoC‐MoSe2 exhibits the smallest degree of Li2S2 disproportionation throughout the reduction process. Consequently, the cell with MoC‐MoSe2/C/S cathode delivers an initial discharge‐specific capacity of 841.1 mAh g−1 and long‐term cycling stability with a capacity attenuation rate of 0.08% per cycle at 1.0 C. This work presents a novelty view to design a rational multifunction catalyst for sequentially accelerating the stepwise conversion of polysulfides.

Hierarchical porous cobalt nanoparticles encapsulated in heteroatom-doped hollow carbon as an enhancing multifunctional catalyst for hydrolysis of sodium borohydride and hydrogenation of bromate in water

Multifunctional heterogeneous catalysts have been consistently explored in recent years because of their distinctive catalytic activity in different catalysis areas at once. Here, a cobalt (Co) nanoparticles encapsulated in nitrogen-doped hollow carbon (denoted as Co@NHC) is prepared by two-step modifications of acid etching and high temperature carbonization in the inert atmosphere using a peculiar polyhedral configuration Co-ZIF as an initial template. Benefiting from an intriguing polyhedral configuration hollow structure with high specific surface area and pore volume supplying plentiful active sites, Co@NHC shows exceptional catalytic activity in catalyzing hydrolysis of NaBH4 and hydrogenation of toxic bromate in water. From experimental results, Co@NHC could efficiently enhance the generation of H2 with a H2 generation rate of 1515.4 mL min−1 gcat−1 meanwhile the activation energy (Ea) calculated from Co@NHC/NaBH4 system was only 12.6 kJ mol−1. Besides, the combination of Co@NHC and NaBH4 could further reduce toxic bromate ions into bromide via catalytic hydrogenation with a maximum bromate removal capacity of 390.6 μmol g−1. More importantly, due to its strong magnetization, Co@NHC could be simply recovered after reactions, making it well-preserve the unique structure as well as catalytic activity for multiple continuous recycles in both catalytic applications. Additionally, the plausible reaction mechanisms in catalyzing hydrolysis of NaBH4 and hydrogenation of bromate were also proposed. This work has pioneered a promising approach on preparing an engrossing magnetic heterogeneous Co-based catalyst that is practically applicable in various areas of catalysis.

High-performance pyrite nano-catalyst driven photothermal/chemodynamic synergistic therapy for Osteosarcoma

Osteosarcoma (OS) is an aggressive bone tumor with strong invasiveness, rapid metastasis, and dreadful mortality. Chemotherapy is a commonly used approach for OS treatment but is limited by the development of drug resistance and long-term adverse effects. To date, OS still lacks the curative treatment. Herein, we fabricated pyrite-based nanoparticles (FeS2@CP NPs) as synergetic therapeutic platform by integrating photothermal therapy (PTT) and chemo-dynamic therapy (CDT) into one system. The synthetic FeS2@CP NPs showed superior Fenton reaction catalytic activity. FeS2@CP NPs-based CDT efficaciously eradicated the tumor cells by initiating dual-effect of killing of apoptosis and ferroptosis. Furthermore, the generated heat from FeS2@CP under near-infrared region II (NIR-II) laser irradiation could not only inhibit tumor’s growth, but also promote tumor cell apoptosis and ferroptosis by accelerating •OH production and GSH depletion. Finally, the photothermal/NIR II-enhanced CDT synergistic therapy showed excellent osteosarcoma treatment effects both in vitro and in vivo with negligible side effects. Overall, this work provided a high-performance and multifunctional Fenton catalyst for osteosarcoma synergistic therapy, which provided a pathway for the clinical application of PTT augmented CDT.

Biphasic Nanoalloys‐Based Trifunctional Monolith for High‐Performance Flexible Zn‐Air Batteries and Self‐Driven Water Splitting

AbstractSufficient integration of multiple active moieties and correlated heterostructure engineering are pivotal to optimize the reaction kinetics and the intrinsic activities of heterogeneous electrocatalysts. Herein, an integrated heterostructure of biphasic nanoalloys are constructed, encasing in in situ grown and interlaced nitrogen‐doped carbon nanoflake arrays (CoFe‐NiFe/NC). Well‐designed CoFe‐NiFe/NC owns more accessible active sites and interfacial conjugation effects, jointly accelerating the electron transfer and mass transport for multifunctional electrocatalysis. Such unconventional monolith delivers extraordinary trifunctional activities for hydrogen evolution reaction, oxygen evolution reaction (overpotential of 185 mV at 10 mA cm−2) and oxygen reduction reaction. The superior trifunctionality of CoFe‐NiFe/NC is rationalized with experimental and theoretical elucidation. Results reveal that the modulated electronic synergism between the Ni, Fe‐assisted Co sites and the adjacent N‐bridged carbon matrix decisively favors the appropriate binding of intermediates for promoted redox kinetics. Consequently, stand‐alone CoFe‐NiFe/NC cathode contributes to high‐performance aqueous/flexible zinc‐air batteries (ZABs), exhibiting high power/specific energy and excellent cycling stability. Remarkably, CoFe‐NiFe/NC‐based alkaline water electrolyzer requires merely 1.51 V to reach 10 mA cm−2, and a self‐driven water splitting system yields a high H2 evolution rate. This unique heterostructure monolith would open up opportunities for developing high‐efficiency multifunctional catalysts and advanced energy utilization devices.

Medium-entropy alloy MoCoCu-P as an efficient bifunctional catalyst for water splitting

Medium/high-entropy alloy (MEA/HEA) catalysts have emerged as ideal candidates as multi-functional catalysts owing to their synergistic effects of multiple metal components on the boosted catalytic activity. However, the facile preparation and screening of suitable MEAs element to achieve high catalytic performance still remain challenging. In this work, we successfully synthesized a MoCoCu-P MEA electrocatalyst for water splitting electrocatalysis through a feasible electrodeposition method. The as-prepared MEA demonstrated an overpotential of 276.1 mV (j=10 mA/cm²) for OER with a Tafel slope of 38.3 mV/dec, coupled with an overpotential of 64.7 mV for HER (j=10 mA/cm²) with a Tafel slope of 87.7 mV/dec. Employed in an overall water electrolysis cell, MEA achieved a nearly 100% Faradaic efficiency and superior stability over than 50 hours at a high current density of 50 mA/cm2. X-ray photoelectron spectroscopy (XPS) analysis verify that high-valence Co and Mo are the most active sites for OER, while electron-rich Cu at the presence of P is responsible for the boosted HER in the MoCoCu-P MEA. This study not only provides a feasible electrodeposition strategy to obtain MEA catalysts with high activity and excellent stability, but also sheds fundamental lights on the identification of the active sites in MEA catalysis.

Controllable Chemoselectivity Cascade Reactions for the Synthesis of Phenanthrenols via Palladium-Catalyzed-Suzuki/Heck Reaction and Michael Addition.

Palladium serves as a multi-functional catalyst which is controllable by tuning reaction conditions. This work demonstrated the utilization of a palladium catalyst for the synthesis of phenanthrenols by cascade palladium-catalyzed Suzuki/Heck reaction between chalcone and 2-bromophenylboronic acid, followed by Michael addition. The sequential reaction could be controlled by reactivity of the palladium catalyst in different solvents and concentrations of reagents. This protocol could be applied to a broad range of substrates to give products in low to good yields.

Insight into the catalytic performances of Fe0@chitosan/cellulose green hybrid structure for enhanced photo-Fenton's oxidation of levofloxacin toxic residuals: Pathway and toxicity

A green hybridized structure of Fe0 painted chitosan/cellulose base (Fe0@CS/CF) has been developed using cellulose extracted from sugarcane bagasse along with reduction agents sourced from Khaya senegalensis leaves. The composite was assessed as an affordable, powerful, and multifunctional catalyst for enhancing the degradation of Levofloxacin (LVX) remnants within water supplies via photo-Fenton's interactions. Using a dosage of 0.5 g/L, the Fe0@CS/CF blend demonstrated noteworthy catalytic qualities, resulting in the complete photo-Fenton's degradation of LVX at a level of 25 mg/L after 40 min. However, the complete diminution of organic carbon (TOC) occurred only after 100 min, suggesting the presence of significant intermediate residues. The identified intermediate chemicals and confirmed hydroxyl radicals as the main oxidizer suggest that the degradation pathway involves carboxylation/decarboxylation, hydroxylation, demethylation, and oxidation of quinolone rings. The toxicity properties of untreated LVX solutions and their subsequent oxidized byproducts were assessed by evaluating their inhibiting impact on Vibrio fischeri over various durations. The samples that experienced partial oxidation at initial testing demonstrated a higher level of toxicity in comparison to the parent LVX. However, the sample that was treated for 100 min demonstrated substantial biological safety and a non-toxic nature. The blend of ingredients has a synergistic impact that enhances the uptake, Fenton's, photocatalytic, and photo-Fenton's characteristics of the hosted Fe0 nanoparticles.

Catalytic conversion of crude oil to hydrogen by a one-step process via steam reforming

This work presents a multi-functional NiCoCe-based catalyst for crude oil steam reforming for hydrogen production. Arab Light (AL) and Arab Extra Light (AXL) were centrifuged to reduce the asphaltenes and sequentially steam reformed in a fixed bed reactor. Results showed that the NiCoCe catalyst was stable and highly selective under reaction conditions and in cyclic operation. The physicochemical properties of the catalyst were determined via inductively coupled plasma–optical emission spectrometry, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The high dispersion of the NiCo alloy on a Mg–Al support was crucial for ensuring the hydrocarbon reforming in the presence of heteroatomic species.

Engineered nanozymes for speedy colorimetric biosensing and sensitive cascaded-catalytic determining of norfloxacin

Nanozymes based on default engineering have garnered considerable interest for their ability to effectively imitate natural enzyme catalysis settings for detection. With the widespread use of quinolone antibiotics, it is worth noting that the antibiotic drugs represented by norfloxacin (NOR) are concentration-dependent when used. Therefore, residual or dosage differences in the body can lead to some central toxicity hazards, so monitoring and detection are necessary. Herein, we reported Fe3O4@MIL-101@polypyrroles (PPys) nanozymes with default engineering, which possessed a porous core–shell structure with Fe3O4 as the core and MIL-101 and PPys as the shells in sequence. X-Ray photoelectron spectroscopy (XPS) analysis and density functional theory (DFT) calculation were to guide and analyze the catalytic pathway of peroxidase-like activity. Furthermore, a versatile intelligent colorimetric and sensing platform has been established to achieve sensitive cascaded-catalytic determining norfloxacin (NOR). In addition, NOR has a lower threshold of acceptability detection of 0.14 μM, which is better than the interpreted detection methods. We have firstly explored the detection mechanisms of ascorbate (H2A) and NOR and discovered that NOR could selectively oxidize Fe2+ and support Bi-Bi mechanisms in the process of H2O2 catalysis. Excellent guidelines for the design of multifunctional nanozyme catalysts were provided by the inquiry.

Strong Carbon Layer-Encapsulated Cobalt Tin Sulfide-Based Nanoporous Material as a Bifunctional Electrocatalyst for Zinc-Air Batteries.

Global demands for cost-effective, durable, highly active, and bifunctional catalysts for metal-air batteries are tremendously increasing in scientific research fields. In this work, a strategy for the rational fabrication of carbon layer-encapsulated cobalt tin sulfide nanopores (CoSnOH/S@C NPs) material as a bifunctional electrocatalyst for rechargeable zinc (Zn)-air batteries by a cost-effective and facile two-step hydrothermal method is reported. Moreover, the effect of metal elements on the morphology of CoSnOH nanodisks material via the hydrothermal method is investigated. Owing to its excellent nanostructure, exclusive porous network, and high specific surface area, the optimized CoSnOH/S@C NPs material reveals superior catalytic properties. The as-prepared CoSnOH/S@C NPs electrocatalyst reveals better properties of oxygen reduction reaction (half-wave potential of -0.88 V vs reversible hydrogen electrode) and oxygen evolution reaction (overpotential of 137mV at 10mAcm-2) when compared with commercial Pt/C and IrO2 catalyst materials. Most significantly, the CoSnO/S@C NPs-based Zn-air battery exhibits more excellent cycling stability than the Pt/C+IrO2 catalyst-based one. Consequently, the proposed material provides a new route for fabricating more active and stable multifunctional catalyst materials for energy conversion and storage systems.

Role of Iridium in n‐Pentane Isomerization, Cyclohexane Ring Opening, and Cumene Cracking Over Ir/Pt‐HZSM5

AbstractProducing aromatic compounds sustainably from renewable sources is essential to reduce reliance on fossil fuels. This study aims to elucidate the multifunctional behavior of Ir on Pt‐HZSM5, and their influence on the catalytic activity of n‐pentane isomerization, cyclohexane ring opening, and cumene cracking. The results showed that Ir created another active and Lewis's acid site, which increased the acid sites (H+), thus enhancing the catalytic performance of Pt‐HZSM5. Moreover, Ir inhibited the atomic hydrogen bonding interaction and hence improved the main reaction and suppressed the side reaction. Therefore, the mechanism of the main reaction over Ir/Pt‐HZSM5 can be described as the following steps: (i) Interaction of reactant with H+; (ii) Reaction of carbenium ion intermediate; and (iii) Interaction of a carbenium ion intermediate with H−, followed by desorption. This study provides a comprehensive understanding of the intricate catalytic pathways, offering insights into the design of efficient multifunctional catalysts for various petrochemical applications.

Multicomponent Reductive Coupling for Selective Access to Functional γ-Lactams by a Single-Atom Cobalt Catalyst.

Despite their significant importance to numerous fields, the difficulties in direct and diverse synthesis of α-hydroxy-γ-lactams pose substantial obstacles to their practical applications. Here, we designed a nitrogen and TiO2 co-doped graphitic carbon-supported material with atomically dispersed cobalt sites (CoSA-N/NC-TiO2), which was successfully applied as a multifunctional catalyst to establish a general method for direct construction of α-hydroxy-γ-lactams from cheap and abundant nitro(hetero)arenes, aldehydes, and H2O with alkynoates. The striking features of operational simplicity, broad substrate and functionality compatibility (>100 examples), high step and atom efficiency, good selectivity, and exceptional catalyst reusability highlight the practicality of this new catalytic transformation. Mechanistic studies reveal that the active CoN4 species and the dopants exhibit a synergistic effect on the formation of key acid-masked nitrones; their subsequent nucleophilic addition to the alkynoates followed by successive reduction, alkenyl hydration, and intramolecular ester ammonolysis delivers the desired products. In this work, the concept of reduction interruption leading to new reaction route will open a door to further develop useful transformations by rational catalyst design.