Nanocatalyst For Synthesis Research Articles

Production of biodiesel by using CaO nano-catalyst synthesis from mango leaves extraction

Development and population expansion have the lion's share of driving up the fuel cost. Biodiesel has considerable attention as a renewable, ecologically friendly and alternative fuel source. In this study, CaO nanocatalyst is produced from mango leaves as a catalysis for the transesterification of waste cooking oil (WCO) to biodiesel. The mango tree is a perennial plant, and its fruit holds significant economic worth due to its abundance of vitamins and minerals. This plant has a wide geographical range and its leaves can be utilized without any negative impact on its growth and yield. An analysis was conducted to determine the calcium content in the fallen leaves, revealing a significant quantity of calcium that holds potential for utilization. The catalyst was characterized by different analytic techniques such as XRD, SEM-EDS, FT-IR, and BET analyses. Several parameters impacted on the transesterification process were exploited by conventional transesterification (batch). The result revealed that the optimum reaction was reached at a methanol to oil ratio of 50% w/w, catalyst loading of 3%, temperature of 65℃ and reaction time of 1.5 h with a yield of 93.21%, and the activation energy of the transesterification reaction was found to be 38.906 KJ mol-1. The reaction was verified to be irreversible pseudo-first order based on a linear Arrhenius plot and a high R2 value. The catalyst shows good stability and catalytic activity when it is reused and the yield was found to be 80.293% in the 5th cycle.

The applications of nanocatalysts in the synthesis of heterocyclic compounds

Nanocatalysts in heterocyclic synthesis are a very important direction in producing eco-friendly compounds. These catalysts can be reused up to six times without losing their quantity and efficiency. Most of these nanocatalysts are cheap, available, economical and safe for the environment. In this review, I focused on the synthesis of furans, pyrans, chromenes and thiazoles from nanocatalysts. For example, pyranopyrazoles 8a-c were synthesized by the multicomponent reactions between aldehydes 4a-c, malononitrile (5), ethyl acetoacetate (6) and hydrazine hydrate (7) using titanium dioxide as a nanocatalyst. KEY WORDS: Heterocyclic, Chromenes, Nanocatalysts, Eco-friendly compounds Bull. Chem. Soc. Ethiop. 2025, 39(1), 123-129. DOI: https://dx.doi.org/10.4314/bcse.v39i1.10

TiO2-ZnO based nano catalyst for biodiesel production: synthesis, characterisation, performance & emission study

Biodiesel (BD) production from bio-oil in the agriculture-based economy could minimise the energy dependency on fossil diesel (FD). Viscous properties and lower calorific value of BD restrict their direct application in the DE. These properties of BD can be enhanced by using advanced material (catalyst, adhesive etc) along with by modifying BD preparation processes. The present work deals with the synthesis and characterisation of nanocatalyst (TiO2-ZnO) and their application in BD production from waste cooking oil (WCO) via the transesterification process. Catalyst TiO2-ZnO was characterised by XRD, SEM and FTIR analysis. Catalyst TiO2-ZnO in a 4:1 mass ratio indicates the maximum BD yield. Maximum BD yield of 88% was noticed for molar methanol/WCO ratio – 1:1; catalyst dose – 2.5 g/l; reaction time – 120 min at reaction temperature -65°C respectively. The prepared BD was characterised by FTIR, GCMS, and HNMR analysis and compared their result with fossil diesel. Engine performance confirms that the 20% BD containing BM increases BSFC and EGT by 40 and 8.33% and decreases BTE by 14.26% in comparison with FD. But HC and CO emissions decreased by 50.27 and 57.44% respectively. While CO2 and O2 emissions are increased by 2.65 and 4.76% respectively. Highlights A maximum yield of 88% with TiO2-ZnO (4:1) mass ratio was obtained. BSFC and EGT increased by 40 and 8.33%. HC and CO emissions decreased by 50.27% and 57.44%.

Improving Catalytic Performance via the Synergy of Tensile Lattice Strain and Plasmonic Enhancement in Defective AuPd@Pd Short Nanowires.

The synthesis of bimetallic nanocatalysts with strained crystal lattices has attracted considerable interest. This is because, beyond the electronic structure modifications realized through elemental doping, the strain effect offers an extra mechanism to fine-tune the electronic structures, thereby possibly improving the catalytic performances. We present a method for constructing defective AuPd@Pd short nanowires, achieved through a controlled galvanic replacement reaction between short AuCu nanowires and Pd precursors. Advanced structural analyses using spherical aberration-corrected transmission electron microscopy (AC-TEM) validated the expanded crystal lattice on the nanowire surface and also demonstrated pronounced plasmonic absorption in the UV-vis region. Leveraging both plasmonic absorption and strain effects, the AuPd@Pd short nanowires displayed a higher apparent rate constant compared to Pd nanoparticles. Integrating molecular dynamic simulations with density functional theory calculations revealed that the tensile strain on AuPd@Pd short nanowires benefited the catalytic activity by elevating the d-band center, thereby intensifying the adsorption of p-nitrophenol. The current research introduces a unique method for synthesizing noble metal nanocrystals with specific dimensions and elucidates the rational development of high-performance plasmonic nanocatalysts through synergistic exploitation of the beneficial strain effect.

Evaluation of the synergistic effect of magnetic nanoparticles and Ferrocene-Based 1,2,3-Triazolyl compounds as burning rate catalysts for solid rocket Motors

This work reports the synthesis, characterization, and application of promising nanocatalysts on the thermal decomposition of ammonium perchlorate (AP). Magnetite nanoparticles were functionalized with Ferrocene-derivative groups through chemical and physical methods to obtain these composite materials. The characterization was done using TEM, FTIR, VSM, and TGA techniques. The composite material MNP-Fc2I causes a decrease in the high-temperature decomposition (HTD) of AP to 357 °C. On the other hand, the MNP-Fc1 obtained the lowest activation energy (138 kJ·mol−1), indicating that the reaction may initiate at a relatively high temperature due to the need to overcome the activation energy barrier; once it begins, it proceeds with reduced energy requirements. Furthermore, performing ion exchange with energetic anions results in a decrease in the decomposition temperature of AP for the MNP-Fc1(N3) and MNP-Fc1(DCA) catalysts.

A Robust Synthesis of Co2P and Ni2P Nanocatalysts from Hexaethylaminophosphine and Phosphine-Enhanced Phenylacetylene Hydrogenation.

Metal-rich phases of general formula M2P have demonstrated interesting catalytic activity, e.g., for hydrogen evolution reaction and for hydrogenations in colloidal suspension. The production of well-crystallized nanoparticles of the M2P phase from commercial precursors on a large enough scale is not trivial as the existing routes generally require fairly high reaction temperatures and a large excess of the phosphorus source. Here, we selected a commercial aminophosphine, P(NEt2)3, as the phosphorus precursor (3 equiv or less) to develop a robust synthesis from CoCl2 (respectively NiCl2) that provided crystalline Co2P (respectively Ni2P) nanoparticles with high yields on a 9 mmol scale. Moreover, modification of the M2P nanoparticles via the addition of a molecular Lewis base is a promising route to trigger catalytic activity of the colloidal suspension at a lower temperature. For the hydrogenation of phenylacetylene catalyzed by Co2P and Ni2P nanoparticles, we showed that catalytic amounts of adequate phosphines, such as PnBu3 and also, in some instances, oleylamine, triggered a full conversion at lower temperatures than with the nanoparticles alone. We delineated the most efficient phosphines in the case of a Ni2P catalyst, using a stereoelectronic map of 13 phosphines.

Catalytic merits of Ni0.6Zn0.4Fe2O4/f-MWCNTS–CS–Asp/Ni2+ for tailoring 1H-benzo [4,5] imidazo [1,2-b] [1,2,4]triazepine motifs through green domino strategy

The magnetic nano catalyst mediated synthesis of heterocycles is one of the most fascinating fields of chemistry due to its proven applicability in high-efficiency, eco-friendly and recyclable heterogeneous catalytic system. In order to design a novel Ni0.6Zn0.4Fe2O4/f-MWCNTs–CS–Asp/Ni2+ magnetic heterogeneous catalyst, Ni0.6Zn0.4Fe2O4-decorated multi walled CNTs were modified with crosslinked chitosan with l-aspartic acid entrapped Ni2+ nanoparticles. This nano catalyst showed significant catalytic activity in the synthesis of biologically potent novel seven membered heterocycles embracing fused 1H-benzo [4,5]imidazo [1,21,2-b][1,2,4]triazepine skeleton. Owing to its interesting structure and being an important pharmacophore fragment, it was endeavored to exploit its synthesis. For the first time considering an exquisite and accomplishable access to construct (Kaur et al., 2021; Jiang et al., 2006; Stern, 1980) [1,2,4]triazepine framework. In addition, the structures of synthesized heterocycles and morphology of nano catalyst were corroborated on the basis of various spectroscopical and microscopical techniques. Furthermore, employing ultrasonication as energy source in the synthesis of magnetic nano catalyst employing 3R's (reduce, recycle and reuse), mild reaction conditions with appreciable yield along with no consumption and production of hazardous chemicals put it under the umbrella of green and sustainable approach.

Precise synthesis of In–Bi alloy nanodroplets through controlled surface reactions on a Si(111) surface at ambient temperature

The synthesis of alloy nanocatalysts with controllable sizes and shapes is a critical prerequisite for vapor–liquid–solid (VLS) growth of one-dimensional nanostructures. In this work, we comprehensively examined surface reactions between evaporated In atoms and a Bi thin film on a Si(111) surface at ambient temperature. InBi2 liquid nanodroplets nucleate and grow during initial vapor–solid (VS) reaction between the In vapor and surface Bi atoms, and the reaction proceeds until a saturation point is reached, following which InBi2 begins to catalyze subsequent VLS growth of various nanocrystals under persistent In-beam flux. The scaled size distribution of individual InBi2 nanodroplets could be explained adequately using the classical capillary nucleation theory, which suggests that the simultaneous homogeneous nucleation of InBi2 nanodroplets occurs during the vapor–solid (VS) reaction of In and Bi.

Lattice-Strained Bimetallic Nanocatalysts: Fundamentals of Synthesis and Structure.

Bimetallic nanostructured catalysts have shown great promise in the areas of energy, environment and magnetics. Tunable composition and electronic configurations due to lattice strain at bimetal interfaces have motivated researchers worldwide to explore them industrial applications. However, to date, the fundamentals of the synthesis of lattice-mismatched bimetallic nanocrystals are still largely uninvestigated for most supported catalyst materials. Therefore, in this work, we have conducted a detailed review of the synthesis and structural characterization of bimetallic nanocatalysts, particularly for renewable energies. In particular, the synthesis of Pt, Au and Pd bimetallic particles in a liquid phase has been critically discussed. The outcome of this review is to provide industrial insights of the rational design of cost-effective nanocatalysts for sustainable conversion technologies.

Phase manipulating toward Ni catalysts via lattice nitrogen endows high energy density hydrogen gas battery

Metastable structures commonly generate unique catalytic effects. However, it is challenging to prepare due to thermodynamic limitations. Here, we first propose a nitrogen insertion strategy for Ni phase manipulating in alkaline hydrogen oxidation reaction (HOR). With the incremental lattice nitrogen, face centered cubic (fcc), bi-mixed fcc and N-induced an unconventional hexagonal close packed (N-u-hcp), tri-mixed fcc-Ni/N-u-hcp-Ni/Ni3N and Ni3N phase evolves successively, with corresponding volcanic HOR activities. Specifically, the biphasic fcc-Ni/N-u-hcp-Ni shows highest activity of 67 A g−1. Theoretical calculations show that lattice nitrogen reduce the formation energy of biphasic Ni, and this biphasic structure could provide electron rich interface to optimize the adsorption of H* and OH*. As a proof-of-concept for Ni-H2 battery, the gas diffusion electrode prepared with this biphasic Ni catalyst achieves an 8 Ah Ni-H2 battery with 163 Wh kg−1. This study provides an inspiration for the controllable synthesis of metastable nano-catalysts and demonstrates the efficient catalysis in practical hydrogen energy applications.

Recent Advances in the Use of Controlled Nanocatalysts in Methane Conversion Reactions

This study investigates the utilization of controlled nanocatalysts in methane conversion reactions, addressing the pressing need for the efficient utilization of methane as a feedstock for valuable chemicals and clean energy. The methods employed include a comprehensive review of recent advancements in nanocatalyst synthesis, characterization, and application, as well as the critical analysis of underlying mechanisms and controversies in methane activation and transformation. The main findings reveal significant progress in the design and synthesis of controlled nanocatalysts, enabling enhanced activity, selectivity, and stability in methane conversion reactions. Moreover, the study highlights the importance of resolving controversies surrounding metal–support interactions for rational catalyst design. Overall, the study underscores the pivotal role of nanotechnology in shaping the future of methane utilization and sustainable energy production, providing valuable insights for guiding future research directions and technological developments in this field.

Synthesis of ultrastable silver catalyst supported on alumina nanofibers for carbon monoxide combustion

A catalyst consists of fine aggregates nanoflowers of alumina as support and uniform coating of silver as active component was fabricated to oxidize carbon monoxide. The alumina nanofibers synthesized via a simple electrochemical method. XRD and FE-SEM analysis showed that the thickness of silver deposit was in the range of subnanometer. Elemental mapping also showed a uniform distribution of silver. Also, BET and EDX tests were performed to measure the specific surface area and elemental composition of the catalyst, respectively. Its catalytic activity was measured, and at GHSV equal to 60000 ml/h.g, the end temperature of the oxidizing reaction was 175°C. By increasing the GHSV to 120,000 ml/h.g, the end temperature of the reaction reached 190°C. The thermal stability of the catalyst was also high, as the specific surface area of the catalyst changed from 87m2/g to 51m2/g by increasing the temperature from ambient temperature to 900°C. Due to the high stability of alumina, the structure of the catalyst is always stable. On the other hand, feasibility studies have been given special attention to the advancement of the project. Therefore, for the synthesis of nanocatalyst, available precursors and a simple method have been used, so there will be no problem in the mass production of the catalyst. It is hoped to be able to synthesize nanocatalysts with similar structure and mass production capability for other chemical reactions with this method.

Ultrasound‒induced facile synthesis of spinel CoFe2O4‒PAC magnetic nanocatalyst for remediation of hypersaline petrochemical wastewater: Degradation mechanism, biodegradability enhancement and phytotoxicity mitigation

In this study, magnetic CoFe2O4−PAC nanocatalysts were synthesized through facile hydrothermal and co‒precipitation approaches with ultrasonic irradiation, which were used for the treatment of hypersaline petrochemical wastewater (HPCW). When an ultrasound‒induced synthesis process (US@CoFe2O4‒PAC) was used, a more efficient and stable magnetic spinel CoFe2O4‒PAC nanocatalyst was developed. The application of this nanocatalyst as a PMS activator, not only caused eradication of 90.4% of chemical oxygen demand (COD) of a HPCW after 90 min reaction time under the optimum conditions (pH 5−6, catalyst dose 1.0 g/L and 1.0 mM PMS), but also led to marginal leaching of iron (314 μg/L) and cobalt (95 μg/L) from the nanocatalyst. Recycling experiments over five consecutive runs showed a negligible decrease (7.2%) in COD removal efficiency which proved the stability and reusability of magnetic US@CoFe2O4−PAC. Two main mechanisms of adsorption and catalytic oxidation processes (homogeneous and heterogeneous PMS) are involved simultaneously in the PMS/US@CoFe2O4−PAC system, which are responsible for the destruction of refractory contaminants of HPCW through the generation of SO4•‒ and OH• radicals. COD of HPCW was mainly removed through SO4•− radical attack (73.6%) and the biodegradability of HPCW was enhanced dramatically after 90 min reaction time. The germination index (GI) of raw HPCW was increased 17.1 ± 4.2% and 24.3 ± 8.8% after 15 and 90 min reaction time, respectively, even PMS/US@CoFe2O4−PAC system showed less impact on phytotoxicity mitigation. Hence, it can be recommended to dilute the effluent before using for irrigational purpose. The findings of this study present practical significance of spinel US@CoFe2O4−PAC, which is an environment‒friendly catalyst, easy to handle and can sustain long‒term operation for the treatment of recalcitrant hypersaline wastewater and the other potential practical applications.

Musa acuminata free tepal (MAFT) crop- mediated synthesis of copper oxide nanocatalyst (MAFT-CuO nanocatalyst): Investigation of aerobic oxidation and dye decolourization via eco-friendly approach

Crop development is used to address environmental problems in the industry. Environmental pollutants, particularly humble or toxic chemicals and dyes, are contaminants in industrial wastewater. Recently, green technology has become important for controlling the chemical risks associated with environmental issues. This study focused on valuable crop materials to form green catalysts that can be used to control chemical toxicity in industrial wastewater. In this study, Musa acuminata-free tepal (MAFT) crops and musa were used to mediate the formation of copper nanocatalyst for environmental pollution. The synthesised nanocatalyst was analysed by XPS, XRD, TEM, SEM, FT-IR, GC-EI-MS, and TGA-DSC. The production of Cu–O in the 512 cm−1 peak range was verified by FT-IR analysis. The XRD peaks associated with the cubic crystalline structures of copper (110) and (200) were used to confirm the Musa acuminata-free tepal CuO nanocatalyst. The SEM images of the Cu and CuO nanocatalyst in the Musa acuminata free tepal showed that the particles were almost spherical. The size of the synthesised Musa acuminata free tepal CuO nanocatalyst core-shell nanostructures was identified using HR-TEM. GC-MS investigations also verified the aerobic oxidation of the main alcohol to aldehyde, with a retention time of 30.34. The MAFT was 80 % of CBB G250 dye decolourised at 24 h, and the MAFT-CuO nanocatalyst was decolourised the CBB G250 dye at 80 % in 20 min and aerobic oxidation at the same time (dual application). Furthermore, our nanocatalyst could be effectively recycled without significant loss of catalytic activity, and the use of safe, environmentally benign MAFT-Cu and CuO nanocatalyst is considered a green chemistry approach that helps avoid wastewater treatment. MAFT-Cu and CuO nanocatalyst were successfully synthesised using Musa acuminata free tepal extract assisted by reflux sample preparation system instruments as a new, green, eco-friendly, and fast process for nanocatalyst synthesis. In the past, there have been no reported applications of MAFT-Cu and CuO nanocatalyst for decolourisation and aerobic oxidation. Nevertheless, we were able to accomplish these procedures with the help of CuO and MAFT-Cu nanocatalyst. Therefore, the most effective naturally occurring environmental catalysts for aerobic oxidation processes are MAFT-CuO nanocatalyst. They are non-toxic and environmentally benign, exhibit strong aerobic oxidation catalytic performance, and have long-lasting benefits for water quality. Additionally, they are more recoverable and biodegradable.

Ultrasound-assisted extractive-catalytic removal of micro-organic pollutants in liquid hydrocarbon fuels using highly active ZnO nanoparticles supported zinc-substituted phosphotungstate

To produce ultra-low sulfur diesel (ULSD), it is necessary to remove compounds such as 2-methylthiophene and 3-methylthiophene that cannot be isolated by conventional industrial methods. This paper presents, a phosphotungstate catalyst improved with zinc atoms placed on the surface of super active zinc oxide nanoparticles and is able to switch between two phases using a hydrophobic ionic liquid (transfer agent). Here, is a description of the synthesis of the α-keggin type hybrid nanocatalyst and its application for the removal of 2- methylthiophene and 3-methylthiophene. The nanocatalyst was subjected to various characterization techniques, including Fourier Transform Infrared Spectrometer (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) Surface Area Analysis, Barrett-Joyner-Halenda (BJH) pore size and volume analysis and Energy-dispersive X-ray analysis(EDAX). The optimized conditions for the ultrasound-assisted extractive-catalytic oxidative desulfurization (UA-ECODS) process were determined using a statistical design, specifically the Box-Behnken design (BBD), which was proposed as a plan for designing experiments and studying the behavior of the parameters. The optimal conditions, which encompass four parameters, namely ultrasonic time, reactor temperature, amount of nanocatalyst, and oxidant concentration, are archived as 14.43 min, 40.52 °C, 86.27 mg catalyst, and 24 % H2O2 Respectively. The results indicated that the removal efficiency was higher for 2- methylthiophene than 3-methylthiophene. The paper concludes that the UA-ECODS method utilizing the synthesized nanocatalyst is a promising and effective approach for desulfurizing of liquid hydrocarbon fuels.

Facile one-pot synthesis of ternary Fe doped Cu-ZnO nanocatalyst: An efficient and recyclable solar light driven photocatalyst

Currently, nanoparticles are regarded as excellent materials for degrading and removing dyes due to their beneficial surface features and chemical reactivity. Herein, Cu doped ZnO (CZ) was co-doped with Fe (FCZ) at different concentrations (2, 3, 4 and 8 wt% with respect to CZ) via simple one-step co-precipitation approach. The structural, surface morphology, surface properties, optical and photocatalytic performance of prepared samples were studied. Due to the doping of Fe, the band gap of CZ reduced from 2.7 eV to 2.29 eV, which is beneficial for absorbing visible light. Among doped CZs, 4 wt% Fe-doped CZ (4FCZ) exhibited 97.1% methylene blue (MB) degradation at neutral pH under 60 min of sunlight exposure. Furthermore, the effect of initial concentration of dye, catalyst load, and pH on the degradation process was investigated. The remarkable photocatalytic activity of 4FCZ nanoparticles can be attributed to their advantageous surface properties, such as their high specific surface area, heterostructure morphology, and mesoporous nature. Scavenger study identified •O2−, e−, and h+ as main reactive species. Pseudo-first order kinetics revealed degradation order: 4FCZ>8FCZ>3FCZ>2FCZ>CZ. 4FCZ showed recyclability with 90.9% MB degradation after three cycles. Mineralization of MB was analysed by COD and LC-MS studies. Fe-doped CZ emerges as a promising, cost-effective wastewater treatment under sunlight without special equipment. This study provides new insights on synthesis of ternary nanocatalyst for dye degradation.

Carbon-dot liposome–based synthesis of gold nanocatalysts for efficient reduction of 4-nitrophenol in wastewater

Supported metal nanoparticles (NPs) having high catalytic activity and stability hold great promise in many fields including catalytic wastewater treatment. These NPs can be effectively stabilized by the suitable carriers to achieve satisfactory long-term stability and increased recyclability. Compared with common solid-state supports, catalyst supports with dynamic behavior are expected to endow active sites with additional degrees of freedom for enhanced catalytic performance. Here, a novel dynamical nanocatalyst support utilizing lamellar vesicles formed via self-assembly of lipid-like carbon dots was devised for in situ growth of gold NPs decorated carbon-dot liposomes (AuNPs@CDLs) in catalytic reduction application. CDLs with abundant carbon domains and surface functional groups are ideal hosts for carrying high-density Au NPs, which are beneficial for providing large number of active sites. CDLs also endow high substrate entrapment and adsorption capacity and thereby improve the overall catalytic performance. Our results reveal that AuNPs@CDLs exhibited superior catalytic activity than unsupported Au NPs for catalytic reduction of 4-nitrophenol (4-NP) with sodium borohydride. The increased fluidity in the vesicle membrane also leads to an enhancement of catalytic efficiency. AuNPs@CDLs have been successfully applied in industrial wastewater treatment, with results of almost complete degradation of 4-NP within 3 min. As a dynamically self-assembled support, CDLs can not only improve the stability against salt-induced aggregation and reusability of immobilized metal nanocatalysts, but also enhance the accessibility of active sites through the intrinsic fluidity of vesicle membranes.

Highly efficient micropollutant decomposition by ultrathin amorphous cobalt-iron oxide nanosheets in peroxymonosulfate-mediated membrane-confined catalysis

Applications of advanced oxidation processes (AOPs) in water treatment require addressing technological challenges such as developing low-cost techniques for nanocatalyst synthesis, overcoming mass transfer limitations, and enhancing the yield of reactive oxygen species (ROS). This study employs a simple sodium borohydride (NaBH4)-based reduction technique for synthesizing ultrathin amorphous cobalt-iron oxide nanosheets (A/Co3-Fe ONS) to activate peroxymonosulfate (PMS). These nanosheets were found to outperform crystalline nanosheets due to their abundant reactive sites, oxygen vacancies, and capability to produce ROS through O–O and S–O bond cleavage. Due to the nanoconfinement effect, converting A/Co3-Fe ONS into a lamellar membrane significantly enhances reactivity and efficacy (1290 times) compared to batch PMS-mediated AOP reactors. Quenching experiments, solid-state and solution-based electron paramagnetic resonance (EPR) spectroscopy facilitated delineation of the reaction mechanisms involving both radical and nonradical pathways. Finally, the A/CoFeOx membrane achieved efficient removal (>95 %) of various organic micropollutants (OMPs), ultrafast destruction (318 ms), and excellent stability (48 h) through redox-recycling facilitated by the redox-potential difference and oxygen vacancies. This strategy offers a low-temperature cost-effective alternative and may be considered for scale-up in water treatment.

Silica Encapsulation Strategy for Protection and Controllable Synthesis of Nanocatalysts

Silica Encapsulation Strategy for Protection and Controllable Synthesis of Nanocatalysts

Flash Joule‐heating synthesis of MoO2 nanocatalysts in graphene aerogel for deep catalytic oxidative desulfurization

AbstractUltra‐high‐temperature flash Joule‐heating of organometallic precursor‐embedded reduced graphene oxide (rGO) aerogel represents a highly efficient approach for the ultrafast production of nanocatalysts, while such a methodology has been scarcely applied to 3D nanocarbon‐based aerogel monoliths. Herein, we demonstrate the rapid synthesis of MoO2 nanoparticles within the aerogel matrix via a 1‐s high‐temperature flash Joule‐heating process (~1700°C), resulting in the formation of the hybrid MoO2@rGO aerogel with uniformly distributed nanoparticles. Nitrogen adsorption/desorption analysis indicates discernible internal microstructural disparities attributed to the additional 1‐s flash‐heating and the substantial generation of MoO2 nanoparticles. This aerogel exhibits exceptional catalytic functionality, achieving up to 99.8% efficiency in converting dibenzothiophene to dibenzothiophene sulfone. Density functional theory calculations provide insights into the catalytic mechanism, revealing that the Mo center shows accumulated electron density contributed from the electron‐rich graphene substrate. This electron density enhancement significantly enhances the catalytic activity, enabling deep desulfurization. The proposed flash nanocatalyst synthesis approach presented here can be extended to fabricate multimetallic nanocatalysts and high‐entropy alloys within the cylindrical aerogel entity, exhibiting great potential for applications in industry‐relevant flow chemistry, electrochemistry, industrial catalysis, and beyond.