Inexpensive Catalyst Research Articles

Ambient Sunlight Driven Photothermal Green Syngas Production at 100 m3 Scale by the Dynamic Structural Reconstruction of Iron Oxides with 38.7% Efficiency

AbstractAmbient sunlight‐driven photothermal green syngas production via reverse water‐gas shift (RWGS) reaction is important for carbon neutrality, which lacks efficient and inexpensive catalysts at low temperatures. This studydemonstrates that the scalable Fe3O4 supported with K atoms modified Ag nanoparticles (AgK/Fe3O4) exhibits a RWGS CO production rate of 1089 mmol g−1 h−1 at 300 °C and 100% CO selectivity through dynamic structural reconstruction, surpassing all reported platinum‐based catalysts. In situ characterization and theoretical simulation indicate that the AgK nanoparticles activate H2 to reduce Fe3O4 as metallic Fe. Subsequently, the metallic Fe spontaneously reacts with CO2 to form CO and Fe3O4, thereby facilitating low‐temperature RWGS. Owing to its superior low‐temperature performance, AgK/Fe3O4 equipped with a homemade photothermal device achieves one sun‐driven photothermal RWGS with a CO production rate of 1925 mmol g−1 h−1 and a 38.7% solar to enthalpy energy conversion efficiency. Furthermore, the enlarged outdoor demonstration yields 100.6 m3day−1 of green syngas with an H2/CO ratio of 3. This work paves the way for designing efficient platinum‐free CO2 hydrogenation catalysts and introduces a new approach for sunlight‐driven scalable green syngas production.

Heteroatoms doping for modulation of sp3-hybridized carbon sites for highly efficient bio-electroreduction of oxygen in microbial fuel cells

Due to the fact that single chamber microbial fuel cells (SC-MFCs) generally require efficient, stable, and inexpensive cathode catalysts to promote bioelectricity generation performance, metal-free catalysts have attracted increasing attention in SC-MFCs. However, enhancing the electrocatalytic activity of the oxygen reduction reaction (ORR) using metal-free catalysts remains a challenge. This study introduces a metal-free porous catalyst by synchronously doping phosphorus (P) and nitrogen (N) atoms into the biomass-derived carbon skeleton (AB-N-P). The AB-N-P catalyst, displaying half-wave potentials (E1/2) of 0.89 (alkaline) and 0.832 V (neutral), exhibits superior ORR performances compared to most metal-free catalysts and is comparable to some non-precious metal catalysts. Remarkably, it (E1/2: 0.890 to 0.880 V) matches or even exceeds the stability of commercial Pt/C catalyst (E1/2: 0.864 to 0.849 V) after 3000 cyclic voltammetry cycles. Density functional theory (DFT) calculations demonstrate that P and N co-doping synergistically increases the sp3-hybridized carbon content and redistributes charge density, thereby enhancing the catalytic properties and altering the electronic properties of the active sites. In practical applications in SC-MFCs, the AB-N-P electrocatalyst shows exceptional performance, achieving a higher power density (896.4 mW m−2) than that of commercial Pt/C (538.2 mW m−2). This study offers insightful revelations into the modulation of carbon active-sites by doping heteroatoms to carbon skeleton as metal-free catalyst in bioenergy-generation systems.

An experimental and theoretical validation of dual role of Fe on improving the photocatalytic performance of doped mixed phase titania

The present work proposes a strategic approach of using Fe doping to form a mixed-phase TiO2 direct Z-scheme catalyst at low onset temperature. The doping-induced modifications are explained from the experimental and theoretical viewpoint. Fe-doped Z-scheme-based mixed-phase TiO2 at optimal calcination temperature (TiFe-400) exhibits maximum photon absorption and reduces charge carrier recombination, enhancing photocatalytic and PEC performance. TiFe-400 has the highest rate constant for the degradation of MB (0.084 min−1 under solar irradiation) and showed exceptional photooxidation current (0.8 mA, 1.3 V vs Ag/AgCl). The Z-scheme formation significantly inhibits the recombination of photocarriers, resulting in a directed migration of charge carriers to the high redox potential mixed-phase TiO2. This migration is validated by identifying the primary reactive species participating in the photocatalytic process. This work, demonstrating both experimental and theoretical approaches, may provide valuable insight into designing stable and inexpensive catalysts for dual applications on an industrial scale.

A‐site Regulated (PrBa)xCo1.5Fe0.5O6‐δ Double Perovskite Oxides: Highly Active and Durable Electrocatalysts for the Enhanced Oxygen Evolution Reaction

Oxygen evolution reaction (OER) represents a significant bottleneck in many energy technologies such as electrochemical water splitting, metal‐oxygen (O) batteries, and solid oxide fuel cells (SOFCs), because of the complexity of the reaction process. Double perovskite oxides (ABO3), recognized for their compositional flexibility, have emerged as excellent OER activity and stability. This study investigates the catalytic potential of B‐site ordered double ABO3 with (PrBa)xCo1.5Fe0.5O6‐δ (PBCF‐x, x=0.9‐1.1) in alkaline media. The results reveal that PBCF‐0.9, characterized by an A‐site deficient composition, exhibits exceptional OER activity. It demonstrates a low Tafel slope of 76.12 mV⋅dec‐1 and a low overpotential (η) of 270 mV at 10 mA⋅cm‐2. Notably, the intrinsic OER activity of PBCF‐0.9 is 25% higher than that of the stoichiometric PBCF‐1.0. Additionally, PBCF‐0.9 exhibits remarkable durability, as evidenced by its stable performance during a 6‐hour chronopotentiometry (CP) test and minimal microstructural changes. These results underscore the effectiveness of A‐site deficiency in optimizing the structure of double ABO3 for improved OER performance. This approach presents a promising strategy for designing highly efficient, stable, and inexpensive catalysts for energy‐related applications.

Photocatalytic Diheteroarylation of [1.1.1]Propellane for the Construction of 1,3-Diheteroaryl Bicyclo[1.1.1]pentanes.

Herein, we report a visible light-induced diheteroarylation reaction of [1.1.1]propellane to synthesize 1,3-diheteroaryl bicyclo[1.1.1]pentanes (BCPs). In this approach, heteroaryl radicals are generated from heteroaryl halides via photocatalysis and subsequently added to [1.1.1]propellane. The in situ generated BCP radicals are then trapped by various heterocycles to furnish 1,3-diheteroaryl BCPs. Notably, this strategy features metal-free, mild conditions and utilizes inexpensive catalyst. For the first time, the diheteroarylation of [1.1.1]propellane could be achieved via a radical strategy, allowing for the efficient synthesis of 1,3-diheteroaryl BCPs with various applications in organic and medicinal chemistry.

ZnS-zeolitic imidazolate framework nanostructure anchored on Ni nanowires as a bifunctional electrocatalyst for high-efficiency overall water splitting

The design and construction of stable and inexpensive bifunctional catalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) present a challenge in electrocatalytic water splitting. In this study, we utilized zeolitic imidazolate frameworks-8 (ZIF-8) as the precursor to fabricate ZnS-ZIF-8 via facile sulfidation processes. The ZnS-ZIF-8 nanostructures were anchored on the surface of the nickel nanowire (denoted as Ni NWs@ ZnS-ZIF-8 nanocomposite) and their catalytic activity for HER, OER, and overall water splitting were studied. The prepared Ni NWs@ ZnS-ZIF-8 revealed a low overpotentials value of 90 and 260 mV at 10 mA cm−2 for HER and OER in 1.0 M KOH solution, respectively. The alkaline electrolyzer assembled by Ni NWs@ ZnS-ZIF-8 provides a low cell voltage of 1.61 V at 10 mA cm−2 current density to boost the overall water splitting and robust stability for 15 h. The superior electrocatalytic activity of Ni NWs@ ZnS-ZIF-8 is owing to the facile and effective electron transport of Ni NWs, accessible active sites of ZnS-ZIF-8, and as well as the synergistic effect of the nanocomposite structures. This finding presents a viable methodology for synthesizing a proficient noble-metal-free catalyst for energy conversion and storage.

NiFe2O4 Nanoparticles: An Efficient Catalyst for One-Pot Three Component Synthesis of Acridinediones Derivatives

A nickel ferrite nanocatalyst was synthesized in the presence of simple and cost-effective polysorbates assisted sol gel method as an effective catalyst has been successfully used for one pot multicomponent Hantzsch condensation reaction of different aromatic aldehydes, dimedone and ammonium acetate under solvent-free condition at 110 °C-120 °C. The highlights feature for the synthesis of acridinediones are the recyclability of catalyst, solvent-free reaction condition, use of inexpensive catalyst, highly efficient, facile product isolation, clean reaction, nontoxic substances and great yields in short reaction time. The recovered catalyst can run four times without loss its activity.

One-pot synthesis of dihydropyrimidinone and polyhydroquinoline derivatives with natural deep eutectic solvents (NADESs): Alternative to toxic organic solvents and environmental eco-friendly

Natural deep eutectic solvents (NADESs) have emerged as a novel class of solvents with properties reminiscent of ionic liquids while offering additional advantages in terms of cost, environmental impact, and synthesis. This article focuses on the applications of NADESs of mannose:urea and glucose:dimethylurea as inexpensive, accessible, and reusable catalysts in the synthesis of dihydropyrimidinone and polyhydroquinoline derivatives. The results demonstrate significant yields for both dihydropyrimidinones (47–99%) and polyhydroquinolines (90–97%) reactions using mannose:urea and glucose:dimethylurea as catalysts. The advantages of NADESs as catalysts include their simple and reproducible preparation, low cost, environmentally benign nature, long-term durability, and tunable properties. This NADESs can also be recovered and reused for four times without a significant loss of activity.

NHC-Catalyzed Umpolung Driven Intramolecular Cyclizations for the Generation of 3,4-Cycloheptanone Annulated Tetracyclic Indole Derivatives.

In this Letter, we disclose the development and exploitation of umpolung reactivity of N-heterocyclic carbene (NHC) organocatalysts in generating tetracyclic indole derivatives with the introduction of a cycloheptane ring forming event. The NHC-catalyzed intramolecular vinylogous Stetter, Stetter, benzoin, and formal cross-dehydrogenative coupling transformations have been executed, enabling the construction of 3,4-cycloheptannulated indole derivatives in good to excellent yields. The developed protocols utilize an inexpensive catalyst and feature operational simplicity, atom economy, gram-scale syntheses, and postsynthetic availability.

Earth-abundant catalyst for modification of wheat straw to enhance ammonia mitigation from fertilized alkaline soil

In this study, inexpensive earth-abundant catalyst of Co/TiO2 is coupled with a low-temperature modification approach to enhance NH3 adsorption capacity on wheat straw (WS). The highest NH3 uptake achieved is 111.9 mg/g, with 80.8 % retention even after 3 h of desorption. Mechanistic investigation indicates that the enhanced adsorption capacity stems from Co/TiO2, which facilitates generation of reactive oxygen species, leading improved ultra-micropore structure that enhances the interaction between NH3 and oxygen-containing functional groups through a trapping effect. The robust stability of adsorbed NH3 is attributed to the formation of amides or amines. Incorporation of only 1 wt% WS-Co to urea-fertilized alkaline soil reduced NH3 volatilization by 83.1 %. The significant effect is primarily attributed to the excellent adsorption capacity of WS-Co, rather than alterations in the relative abundance of the microbial community. These findings present a novel approach for development of effective fertiliser additive to mitigate NH3 volatilization from alkaline soil.

Valence electronic engineering of hollow-nanocube-structured CoFeNi-layered double hydroxides for highly efficient oxygen evolution

The sluggish kinetics of oxygen evolution reaction (OER) and the high-cost of catalysts currently limit the large-scale industrialization of hydrogen production through water electrolysis, so developing efficient and inexpensive catalysts is a top priority. Herein, we employed a facile solvent method to synthesize a well-defined hollow nanocube-structured CoFeNi layered double hydroxide (LDH) with an optimized valence electronic structure of metal sites as an efficient electrocatalyst for accelerating the kinetics of OER. The optimal catalyst with the regulated valence electronic structure exhibited a strong synergistic catalytic effect and an excellent activity and stability. It achieved a lower overpotential of 294 mV at 100 mA cm−2, and high durability exceeding 100 h at 1 A cm−2, surpassing the performance of commercial Ir-/Ru-based catalysts. The optimized the coordination environment and valence electronic structure of metal sites can definitely serve as active centers for triggering OER, thereby improving the intrinsic electrocatalytic performance.

Highly efficient selective hydrogenation of furfural to tetrahydrofurfuryl alcohol over MOF-derived Co-Ni bimetallic catalysts: The effects of Co-Ni alloy and adsorption configuration

The targeted conversion of furfural (FA) over inexpensive catalyst is a critical and challenging project. Herein, CoNi alloy catalysts (xCoyNi/C) were prepared through one-step pyrolysis of metal–organic frameworks and used in furfural (FA) hydrogenation to tetrahydrofurfuryl alcohol (TFOL). The formation of CoNi alloy leads to a reconfiguration of the electronic structure on the metal surface, which affects the adsorption of functional groups on FA and furfuryl alcohol (FOL). In situ FT-IR analysis and DFT calculations verify that bimetallic CoNi alloy catalyst exhibits more suitable reactants adsorption and hydrogenation rate in comparison with the monometallic Co and monometallic Ni catalysts. Meanwhile, CoNi alloy significantly reduces the activation barrier from FOL to TFOL. Hence, the 1Co1Ni/C catalyst gives the highest TFOL yield of > 99 %. This study provides a simple strategy for the preparation of alloy catalysts for tuning product selectivity and presents practical potential for upgrading biomass-derived platform molecules.

Hydrothermal liquefaction of southern yellow pine with downstream processing for improved fuel grade chemicals production

The hydrothermal liquefaction (HTL) technique for liquefying lignocellulose biomass feedstock is often associated with low biocrude yield and poor fuel properties. This study examined the HTL of southern yellow pine sawdust and the hydrotreatment (HYD) of produced biocrudes in an effort to address these challenges. Pine HTL treatment was performed within water and water–ethanol mixed reaction medium at 250, 300, and 350℃ temperatures using metallic iron (Fe) as a catalyst. The rising reaction temperature in a water medium and increasing ethanol content in a mixed reaction medium were found to be effective in enhancing the biocrude yield from the non-catalytic pine HTL process. Maximum non-catalytic biocrude yield of 18 wt.% was produced in water at 350℃, whereas the ethanol and water (1:1 on mass basis) mixture generated the highest biocrude yield of 34 wt.% at 300℃ without any catalyst. The iron catalyst facilitated a maximum of 29 wt.% of biocrude yield as opposed to 18 wt.% without the catalyst at 350℃ in water. The use of an iron catalyst also raised the calorific value of produced biocrudes by 2.5–14 % within 250-350℃ in both water and water–ethanol media. The catalytic and non-catalytic biocrude products were chosen to undergo HYD treatment at 400 °C under high hydrogen pressure (initial 1000 psi) using an alumina-supported cobalt-molybdenum catalyst. The HYD treatment reduced the oxygen content of upgraded oils by 36–60 % compared to the parent HTL biocrudes with 35–37 MJ/kg calorific values. The simulated distillation detected the maximum gasoline range compounds in upgraded oil from catalyst and water–ethanol conditions, whereas the GC–MS analysis revealed the production of increased aromatic hydrocarbons in all upgraded HYD oils. This work has demonstrated the potential of ethanol and inexpensive iron catalyst in enhancing the biocrude production from pine, which could be upgraded to better fuel using the HYD process.

Zn-O-Sn covalency interface governs the intrinsic activity of the Zn2SnO4/SnO2 heterostructure for boosting hydrogen peroxide production

Electrocatalytic production of hydrogen peroxide (H2O2) from oxygen is vital for sustainable clean fuel. Developing highly active, stable, and inexpensive catalysts for H2O2 remains a top priority but is still challenging. In this study, an atomic-shared heterointerface was constructed between Zn2SnO4 and SnO2 via a self-templating co-precipitation method. Theoretical and experimental analysis confirms the delocalization effects of electrons within the Zn2SnO4/SnO2 spinel structure. The resulting Zn-O-Sn bridge (asymmetric sites) modulates electronic transport at the interface, and the intensified Zn-O bond facilitates proton adsorption and transfer kinetics. Moreover, strong interface coupling between Zn2SnO4 and SnO2 enhances electron transfer, which effectively promotes the *OOH intermediate favorable for H2O2 production, boosting H2O2 selectivity of nearly 97 %. The high production rate of 8.19 mol gcat−1 h−1 and excellent stability during long-term operation over 24 h. This work provides strategic insights into developing efficient H2O2 catalysts and other catalytic applications.

Microwave and ultrasound-assisted green protocols for 5-methylthiazole induced Betti bases: molecular docking, in-silico pharmacokinetics, and anticancer activity studies

ABSTRACT Herein, we describe an efficient one-pot three-component microwave and ultrasound-endorsed approaches for synthesizing distinct 5-methylthiazole induced Betti bases (5-methyl-thiazol-2-ylamino-aryl-benzylnapthols) employing silica sulfuric acid (SSA, silica-OSO3H) as an active heterogeneous acid catalyst. The title compounds produced in good yields (86–95%) from naphthalen-2-ol, 5-methylthiazol-2-amine, and assorted aryl aldehydes; and structurally characterized by spectral and elemental analyses. A comprehensive comparative study of conventional, ultrasonic, and microwave-irradiated synthetic routes has been achieved by optimizing various reaction parameters. These new protocols provide several advantages, including the use of an inexpensive, non-toxic, and reusable catalyst. Additionally, they benefit from mild reaction conditions, short reaction times, and simple workup and purification procedures, thereby increasing their practicality. Furthermore, the synthesized compounds were evaluated for their anticancer potency against A-549 (lung cancer) and A-498 (kidney cancer) cell lines, with scaffold IVa demonstrating excellent (GI50 < 10 µg/mL) inhibitory activity against A-549. Additionally, molecular docking was performed to investigate potential binding interactions between ligands and proteins. Scaffold IVa exhibited the best docking with cancerous target proteins 1M17 (−8.9 kcal/mol) and 1M14 (−7.2 kcal/mol), thereby supporting our bio-activity studies.

Copper nanoparticles anchored on nitrogen-doped carbon nanofibers derived from MOFs and bacterial cellulose: Advanced electrocatalysts for oxygen reduction in microbial fuel cells

The development of efficient and inexpensive cathode catalysts contributes to energy conservation. Herein, nitrogen-doped carbon nanofiber (CNF) composites (Cu@N-CNFs) loaded with copper nanoparticles were successfully synthesized as cathode electrocatalysts for microbial fuel cells (MFCs), utilizing metal-organic frameworks (MOFs) and bacterial cellulose (BC) as precursors. The characterization results show that Cu@N-CNFs has a large specific surface area and contains catalytic active substances such as pyridine nitrogen and graphite nitrogen, along with that the graphitization degree of carbon skeleton structure is high. Therefore, Cu@N-CNFs has outstanding catalytic performance in alkaline and neutral environments, with half-wave potentials of 0.83 V and 0.78 V, as well as limiting current densities of −5.70 mA cm−2 and −5.73 mA cm−2, respectively. Moreover, these performances are comparable to those of Pt/C. The composite material is coated on the surface of the carbon cloth and processed into MFC cathode, which has a good improvement in its power production performance.

Alkene Isomerization Catalyzed by a Mn(I) Bisphosphine Borohydride Complex.

An additive-free manganese-catalyzed isomerization of terminal alkenes to internal alkenes is described. This reaction is implementing an inexpensive nonprecious metal catalyst. The most efficient catalyst is the borohydride complex cis-[Mn(dippe)(CO)2(κ2-BH4)]. This catalyst operates at room temperature, with a catalyst loading of 2.5 mol %. A variety of terminal alkenes is effectively and selectively transformed into the respective internal E-alkenes. Preliminary results show chain-walking isomerization at an elevated temperature. Mechanistic studies were carried out, including stoichiometric reactions and in situ NMR analysis. These experiments are flanked by computational studies. Based on these, the catalytic process is initiated by the liberation of "BH3" as a THF adduct. The catalytic process is initiated by double bond insertion into an M-H species, leading to an alkyl metal intermediate, followed by β-hydride elimination at the opposite position to afford the isomerization product.

Cost‐Effective Carbon Quaternization with Redox‐Active Esters and Olefins

AbstractQuaternary carbons are embedded in various natural products, pharmaceuticals, and organic materials. However, constructing this valuable motif is far from trivial. Conventional approaches mainly rely on classical polar disconnections and encounter bottlenecks concerning harsh conditions, functional group tolerance, regioselectivity, and step economy. In this context, Kawamata, Baran, Shenvi, and co‐workers recently demonstrated that two feedstock chemicals, alkyl carboxylic acids and olefins, could be utilized to construct tetrasubstituted carbons in the presence of an inexpensive iron porphyrin catalyst and a suitable reductant combination through quaternization of the radical intermediates. The method enables access to various sterically encumbered quaternary carbons under mild and robust conditions. Taking a complete detour from conventional approaches, the present heteroselective radical–radical coupling simplifies the synthesis of quaternary carbon‐containing molecules through an innovative and distinctive disconnection approach.

Cost-Effective Carbon Quaternization with Redox-Active Esters and Olefins.

Quaternary carbons are embedded in various natural products, pharmaceuticals, and organic materials. However, constructing this valuable motif is far from trivial. Conventional approaches mainly rely on classical polar disconnections and encounter bottlenecks concerning harsh conditions, functional group tolerance, regioselectivity, and step economy. In this context, Kawamata, Baran, Shenvi, and co-workers recently demonstrated that two feedstock chemicals, alkyl carboxylic acids and olefins, could be utilized to construct tetrasubstituted carbons in the presence of an inexpensive iron porphyrin catalyst and a suitable reductant combination through quaternization of the radical intermediates. The method enables access to various sterically encumbered quaternary carbons under mild and robust conditions. Taking a complete detour from conventional approaches, the present heteroselective radical-radical coupling simplifies the synthesis of quaternary carbon-containing molecules through an innovative and distinctive disconnection approach.

Lignin-MOF hybrid polymetallic composites for selective hydrogenolysis of cellulose derived 5-hydroxymethylfurfural

The development of green, effective and inexpensive catalysts was important for the catalytic transfer hydrogenation of 5-hydroxymethylfurfural (HMF) to prepare 5-methylfurfuryl alcohol (MFA). The assembly of sodium lignosulfonate (LS) with NiCo-MOFs through a simple hydrothermal method was reported, and a series of iron-containing polymetallic hybrid catalysts were investigated. The introduction of iron led to the increase of medium strong acid sites and Lewis acid sites in the catalyst and enhanced the adsorption of furan rings, thus improved the catalytic activity. The effects of calcination temperature, iron content, and reaction parameters (including reaction temperature, pressure, hydrogen donor solvent) were all studied in detail. It was found that HMF could be completely converted over Fe@Ni3Co-MOF-LS, with a MFA yield of 88.75 % under the optimal condition (240 ℃, 2 MPa N2 in 4 h) without the presence of hydrogen. This study provided a new perspective for the utilization of lignin resource as carbon-based catalysts for the production of biomass-derived platform chemicals.