Enhancement Of Catalytic Performance Research Articles

Neural Network Potential Calculations for Melamine Adsorption onto Pt (111) Comparing with Density Functional Theory

Abstract The investigation on Pt-adsorbed melamine is important in elucidating the effect of molecular decoration on enhancement of catalytic performance for fuel cells, and is an interesting system where covalent stabilisation between the surface and molecule competes with resonance destabilisation by the coordination. The present work discussed whether graph neural network potentials can predict the adsorption structure with the competition. The most stable structure predicted by preferred potential was consistent with that by density functional theory but underestimated resonance destabilisation.

Substrate access tunnel engineering of a Fe-type nitrile hydratase from Pseudomonas fluorescens ZJUT001 for substrate preference adjustment and catalytic performance enhancement

Substrate access tunnel engineering is a useful strategy for enzyme modification. In this study, we improved the catalytic performance of Fe-type Nitrile hydratase (Fe-type NHase) from Pseudomonas fluorescens ZJUT001 (PfNHase) by mutating residue Q86 at the entrance of the substrate access tunnel. The catalytic activity of the mutant PfNHase-αQ86W towards benzonitrile, 2-cyanopyridine, 3-cyanopyridine, and 4-hydroxybenzonitrile was enhanced by 9.35-, 3.30-, 6.55-, and 2.71-fold, respectively, compared to that of the wild-type PfNHase (PfNHase-WT). In addition, the mutant PfNHase-αQ86W showed a catalytic efficiency (kcat/Km) towards benzonitrile 17.32-fold higher than the PfNHase-WT. Interestingly, the substrate preference of PfNHase-αQ86W shifted from aliphatic nitriles to aromatic nitrile substrates. Our analysis delved into the structural changes that led to this altered substrate preference highlighting an expanded entrance tunnel region, theenlarged substrate-binding pocket, and the increased hydrophobic interactions between the substrate and enzyme. Molecular dynamic simulations and dynamic cross-correlation Matrix (DCCM) further supported these findings, providing a comprehensive explanation for the enhanced catalytic activity towards aromatic nitrile substrates.

Microwave-assisted PMS activation Ti3C2/LaFe0.5Cu0.5O3-P catalysts for efficient degradation of CIP: Enhancement of catalytic performance by phosphoric acid etching

The LaFe0.5Cu0.5O3 perovskite synthesised by MOFs template method was compounded with Mxene Ti3C2, and the novel catalyst M-Ti3C2/LFCO-P was subsequently prepared by phosphoric acid etching. This catalyst effectively induced microwave activation of peroxymonosulfate (PMS), and ciprofloxacin (CIP) was efficiently degraded with a degradation rate reaching 95.48 % within 14 min. Characterization results revealed that the MOFs template method and phosphoric acid etching increased specific surface area (from 25.91 m2/g to 142.41 m2/g) of catalyst and improved its pore size distribution. Phosphoric acid etching successfully introduced phosphorus functional groups and promoted the formation of more oxygen vacancies, thereby significantly enhancing the catalytic activity of the catalyst. The conversion of free radicals and the transformation of free radicals to non-free radicals were demonstrated. Additionally, the catalyst exhibited higher electron transfer efficiency. The catalytic reaction was primarily driven by O2– and 1O2, with OH, SO4−, and e- playing auxiliary roles. Furthermore, the degradation pathway and toxicity of CIP were also evaluated. This work provides a new perspective for improving the catalytic degradation activity of antibiotics by perovskite catalysts.

Enhancing low-temperature CO2 methanation performance by selectively covering Ni with CeO2 to form Ni-O-Ce interface active sites

The methanation of CO2 is crucial for resource utilization, however, achieving excellent CO2 methanation performance with Ni-based catalysts at low temperatures remains highly challenging. In this study, a high-performance 10Ni-0.1Ce/Al catalyst was synthesized using a simple and efficient one-pot combustion method. Unlike other catalysts with the same components, this catalyst exhibits a unique feature where a small amount of the CeO2 promoter is dispersed on the support, while the majority selectively binds to and coats the Ni nanoparticles. This distinctive structure allows it to achieve approximately 80 % CO2 conversion and 99.9 % CH4 selectivity under conditions of 260 °C, 0.1 MPa, and a GHSV of 48,000 mL·g−1·h−1. The high catalytic performance is attributed to the unique structure of Ni nanoparticles and CeO2, which promotes the formation of numerous Ni-O-Ce interface active sites. These Ni-O-Ce interfaces enhance the reducibility and increase the content of weak basic sites in the catalyst. The combination of in-situ DRIFTS and TPSR reveals that the decomposition of bridged HCOO– to *CO is the rate-determining step. The presence of Ni-O-Ce interface active sites in the 10Ni-0.1Ce/Al catalyst facilitates the generation of abundant bridged HCOO– intermediates with higher activity than the 10Ni/Al catalyst, leading to a substantial enhancement in catalytic performance.

Nanozyme Catalytic Performance Enhancement through Defect and Electronic Structure Regulation of Metal-Doped NiCo2O4@Pd.

Spinel oxides have emerged as a promising candidate in the realm of nanozymes with variable oxidation states, while their limited active sites and low conductivity hinder further application. In this work, we synthesize a series of metal-doped NiCo2O4 nanospheres decorated with Pd, which are deployed as highly efficient nanozymes for the detection of cancer biomarkers. Through meticulous modulation of the molar ratio between NiCo2O4 and Pd, we orchestrated precise control over the oxygen vacancies and electronic structure within the nanozymes, a key factor in amplifying the catalytic prowess. Leveraging the superior H2O2 reduction catalytic properties of Fe-NiCo2O4@Pd, we have successfully implemented its application in the electrochemical detection of biomarkers, achieving unparalleled analytical performance, much higher than that of Pd/C and other reported nanozymes. This research paves the way for innovative electron modification strategies in the design of high-performance nanozymes, presenting a formidable tool for clinical diagnostic analyses.

Unlocking Quantum Catalysis in Topological Trivial Materials: A Case Study of Janus Monolayer MoSMg

The emerging field of topological catalysis has received significant attention due to its potential for high‐performance catalytic activity in the hydrogen‐evolution reaction (HER). While topological materials often possess fragile surface states, trivial topological materials not only offer a larger pool of candidates but also demonstrate robust surface states. As a result, the search for topological catalysts has expanded to include trivial schemes. In this study, a novel 2D Janus monolayer, MoSMg, which demonstrates exceptional obstructed atomic insulating behavior, is presented. Crucially, this trivial metallic topological state exhibits clean obstructed surface states, leading to a significant enhancement in catalytic performance for the HER in electrochemical processes, particularly under high hydrogen coverage. Moreover, the edge sites of this MoSMg monolayer exhibit even more superior catalytic activity, characterized by near‐zero Gibbs free energies. In these findings, the way is paved for exploring new avenues in the design of quantum electrocatalysts, especially within the realm of trivial topological materials.

Preparation of defect-enriched Cu-doped FeOCl/g-C3N4Z-scheme composites for efficient photo-Fenton-like performance

In this study, a Z-scheme heterojunction with abundant oxygen vacancies (OVs) formed by Cu-doped FeOCl (Cu-FeOCl) and graphitic carbon nitride nanosheets (CNNS) was successfully synthesized for the removal of tetracycline hydrochloride (TC). The prepared Cu-FeOCl/CNNS had excellent catalytic properties under hydrogen peroxide and light illumination, and the maximum reaction rate was nearly 156 and 48 times higher than that of FeOCl and CNNS, respectively. The enhancement of catalytic performance was due to the synergistic effect of Cu species, Fe species and Ovs, which effectively promoted the adsorption and activation of H2O2, and inhibited the recombination of photogenerated carriers. We further studied the effects of different reaction conditions (catalyst dosage, H2O2 dosage, initial pH, TC concentration, and coexisting substances) on the degradation reaction. 1O2, h+, •O2−, and •OH were active species participating in the reaction, and a possible TC degradation mechanism was studied. This work provided insights into the synergetic action of interface engineering, ion doping, and oxygen defects in the photo-Fenton-like system.

Boosting photo-thermal co-catalysis CO2 methanation by tuning interface electron transfer via Mott-Schottky heterojunction effect

Photo-thermal co-catalytic reduction of CO2 to synthesize value-added chemicals presents a promising approach to addressing environmental issues. Nevertheless, traditional catalysts exhibit low light utilization efficiency, leading to the generation of a reduced number of electron-hole pairs and rapid recombination, thereby limiting catalytic performance enhancement. Herein, a Mott-Schottky heterojunction catalyst was developed by incorporating nitrogen-doped carbon coated TiO2 supported nickel (Ni) nanometallic particles (Ni/x-TiO2@NC). The optimal Ni/0.5-TiO2@NC sample displayed a conversion rate of 71.6 % and a methane (CH4) production rate of 65.3 mmol/(gcat·h) during photo-thermal co-catalytic CO2 methanation under full-spectrum illumination, with a CH4 selectivity exceeding 99.6 %. The catalyst demonstrates good stability as it shows no decay after two reaction cycles. The Mott-Schottky heterojunction catalysts display excellent efficiency in separating photo-generated electron-hole pairs and elevate the catalysts’ temperature, thus accelerating the reaction rate. The in-situ experiments revealed that light-induced electron transfer effectively facilitates H2 dissociation and enhances surface defects, thereby promoting CO2 adsorption. This study introduces a novel approach for developing photo-thermal catalysts for CO2 reduction, aiming to enhance solar energy utilization and facilitate interface electron transfer.

Fabrication of robust layered double-hydroxide nanoparticles for α-Amylase immobilization: Enhancing catalytic performance, stability, and prospective sustainable biocatalysis applications

Fabrication of robust layered double-hydroxide nanoparticles for α-Amylase immobilization: Enhancing catalytic performance, stability, and prospective sustainable biocatalysis applications

Theoretical Insights into Enhancing Catalytic Performance of Al-Cu Alloy for CO2 Electroreduction toward Ethene Production.

The understanding of the reaction mechanism of CO2 electroreduction (CO2RR) is essential for the precise design of catalysts for specific products with high selectivity. In this work, combined with the computational hydrogen electrode model and kinetic energy barrier calculations, CO2RR pathways on Cu(100) and Al1Cu3(100) are intensively investigated. The free energy barrier of the rate-determining step of ethylene formation is reduced from 1.08 eV for *CCOH formation on Cu(100) to 0.51 eV for *CH2OCHOH formation on Al1Cu3(100) and enhances the catalytic activity. The reaction free energy of *CO-*CO coupling is remarkably reduced from 0.86 eV on Cu(100) to -0.43 eV on Al1Cu3(100) and the coupling barrier is reduced from 0.97 to 0.37 eV, suppressing the production of gas phase CO and enhancing the production of C2 products. Furthermore, the selectivity toward C-O breaking of *CH2CHOH on Cu(100) and *CH2CH2OH on Al1Cu3(100) ensures high selectivity toward ethene rather than ethanol.

Axially coordinated dual-atomic-site catalysts for nearly 100% peroxymonosulfate conversion to 1O2 in membrane filtration

Reactive membrane filtration, integrating membrane technology with catalytic processes, offers a promising avenue for efficiently generating and utilizing active species in environmental remediation. Herein, a dual-atom Co-Mn site achieved through axial coordination on N-doped graphene catalyst (sp-CoMn@NG) has been developed and applied in membrane filtration for the targeted removal of specific pollutants. Experimental investigations, alongside density functional theory (DFT) calculations, have substantiated that axial coordination can effectively reduce the adsorption energy and activation barrier of PMS, thereby facilitating nearly 100% conversion of PMS to 1O2 and enhancing catalytic performance. Mechanistic studies further elucidate the 1O2 production mechanism through a superoxide-mediated chain reaction at the axially coordinated Co-Mn center, as well as the inactivation mechanism of catalytic membranes via the addition reaction of 1O2 and phenolic-hydroxyl compounds. This research underscores the intelligent prefabrication of axial coordination in dual-atomic-site catalysts, offering an efficient approach for scalable 1O2 production in reactive membrane filtration.

Study on the specific photodegradation performance of Fe3O4@SiO2@TiO2@MIPs for berberine hydrochloride

Abstract Adsorption is crucial for the performance of photocatalysts in degrading new pollutants. Here, we report a magnetic molecularly imprinted material Fe3O4@SiO2@TiO2@MIPs with a semiconductor/insulator/semiconductor structure, which achieved up to 81% preferential degradation of berberine hydrochloride (BH). The significant enhancement of catalytic performance can be attributed to the interaction between BH and the imprinted cavity, as well as size matching, which proposes new solutions to address the current problem of difficult degradation of new pollutants.

Oxygen vacancy engineering and rare earth ion modification in Er-doped Bi0.5Na0.5TiO3–BaTiO3 for piezo-photocatalysis

The pursuit of high-performance piezo-photocatalysts through structural modifications has been a focal point of investigation within the realm of related scientific disciplines. In this study, we successfully designed Er-doped Bi0.5Na0.5TiO3–BaTiO3 combined with rare earth ion doping and solid solution modification, and the prepared particles exhibited homogeneous grain sizes and optimized concentrations of oxygen vacancies (OV). The synergistic incorporation of OV (accelerator for catalytic reaction) and Er3+ results in an impressive 12-fold enhancement of the piezo-photocatalytic rate when degrading the Rhodamine B dye. The optimal composition 0.96BNT-0.04BT-Er demonstrates outstanding electrochemical properties, including a superior photocurrent response and minimal impedance, highlighting its exceptional performance in piezo-photocatalysis. The fundamental enhancement in catalytic performance can be attributed to the reconfiguration of the band structure of 0.96BNT-0.04BT-Er, which has been meticulously calculated utilizing DRS and VB-XPS and the internal mechanism was explained in detail. This research serves as a source of inspiration for the investigation of solid solutions among piezo-photocatalysts and sheds light on the vital role of band structure in governing catalytic performance.

High-entropy oxide based biomimetic catalysis system enables robust oxidative desulfurization with an excellent regeneration ability

Sulfur-containing compounds from the usage of fossil fuel have severe impacts on the ecological environment and human health. To eliminate sulfur species in fuels, oxidative desulfurization is served as an effective technology, whose core lies in constructing an efficient catalytic system under mild conditions. High-entropy oxides (HEOs) with maximized conformational entropy normally generates abundant catalytically active sites, which are beneficial for the enhancement in catalytic performance. On this basis, a biomimetic catalytic system coupling HEO with deep eutectic solvent (DES) was designed for oxidative desulfurization with molecular O2 oxidant by following the electron transfer mechanism. This catalytic system not only exhibited excellent sulfide removal with O2 oxidant under the ambient pressure, but also can resist the adverse effects of naphthalene and indole in an appropriate concentration range. Uniquely, this HEO was capable to be recovered from the DES phase, ensuring a good recycling and regeneration ability. During the whole catalytic process, the electron was transferred in the sequence of sulfide → DES → HEO → O2. These extraordinary features make it to be an alternative candidate for industrial applications under mild conditions.

A Bioinspired Copper-Pair Catalyst in Metal-Organic Frameworks for Molecular Dioxygen Activation and Aerobic Oxidative C-N Coupling.

Open Cu sites were loaded to the UiO-67 metal-organic framework (MOF) skeleton by introduction of flexible Cu-binding pyridylmethylamine (pyma) side chains to the biphenyldicarboxylate linkers. Distance between Cu centers in the MOF pores was tuned by controlling the density of metal-binding side chains. "Interacted" Cu-pair or "isolated" monomeric Cu sites were achieved with high and low (pyma)Cu side chain loading, respectively. Spectroscopic and theoretical studies indicate that "interacted" Cu pairs can effectively bind and activate molecular dioxygen to form Cu2O2 clusters, which showed high catalytic activity for aerobic oxidative C-N coupling. On the contrary, MOF catalyst bearing isolated monomeric Cu sites only showed modest catalytic activity. Enhancement in catalytic performance for the Cu-pair catalyst is attributed to the remote synergistic effect of the paired Cu site, which binds molecular dioxygen and cleaves the O═O bond in a collaborative manner. This work demonstrates that noncovalently interacted metal-pair sites can effectively activate inert small molecules and promote heterogeneous catalytic processes.

Assessment of the catalytic and biological potential of yttrium and samarium-modified copper ferrite nanomaterials

The present study reports the preparation of crystalline and nanosized copper ferrite (CuFe2O4), Y3+ substituted CuFe2O4 (CuFe1.95Y0.05O4), and Sm3+ substituted CuFe2O4 (CuFe1.95Sm0.05O4) using a simple co-precipitation method. The XRD analysis confirmed the formation of the cubic spinel phase, while XPS studies validated the presence of Cu and Fe in 2+ and 3+ oxidation states respectively. Transmission electron microscopy (TEM) analysis revealed the nanoparticles with a diameter in the range of 10–60 nm. The introduction of fractional amounts of Y3+ and Sm3+ ions in the CuFe2O4 lattice enhanced the reduction of 4-nitrophenol, attributed to decreased particle size facilitating the reduction process. In the case of antimicrobial activity, Candida albican was found to be maximally sensitive to CuFe2O4 and CuFe1.95Y0.05O4, while Pseudomonas aeruginosa was inhibited by CuFe1.95Sm0.05O4. Moreover, a maximum of 61.9 ± 1.91 % anti-Pseudomonas biofilm activity and 75.7 ± 1.28 % DPPH radical scavenging activity was observed for CuFe1.95Y0.05O4 at 200 μg/ml concentration. The improvement in biological activities was attributed to the reduced particle size, crystal structure modification, and increased stability of the CuFe2O4 lattice with substitution. The enhancement in catalytic and biological performance highlighted the effectiveness of minimal Y3+ and Sm3+ concentrations in modulating the properties of CuFe2O4 nanomaterials.

Modulation of Al Distribution in High-Silica ZSM-5 Zeolites for Enhancing Catalytic Performance.

The spatial distribution of framework Al (AlF) has been one of the important factors that affect the catalytic properties of zeolites in diverse chemical reactions; however, the synthesis of high-silica zeolites with special AlF distribution remains a challenge. In this study, we successfully synthesized high-silica ZSM-5 zeolites with a unique AlF distribution by employing pentaerythritol (PET) as an additive in the presence of a few tetrapropylammonium hydroxide (TPAOH). The results demonstrated that the introduction of PET led to a higher proportion of Al atoms located at the sinusoidal and/or straight channels. It was observed that the addition of PET prevented the interaction between TPA+ and tetrahedral [AlO4]- during the crystallization process, resulting in enhanced availability of TPA species in the form of ion-paired TPA+. This effect leads to AlF atoms dominantly distributed away from the intersection and located in narrow channels, where acidic sites more effectively inhibit hydrogen transfer and coke formation. In the reaction of dimethyl ether (DME) to olefins, the catalyst with a unique Al distribution exhibited a significant prolonged catalytic lifetime, surpassing traditional TPA-ZSM-5 by more than 2-fold and maintaining DME conversion above 90% for a maximum of 148 h. The results of multiple pulse experiments also showed that these PET-assisted ZSM-5 zeolites significantly enhanced the selectivity of propene and butene. This approach provides an effective strategy to regulate AlF distribution in high-silica ZSM-5 catalysts with the assistance of neutral alcohol. It holds great potential for application in the synthesis of other high-silica zeolites, thereby enriching the diversity of zeolite catalysis.

Spin-state regulation by secondary coordination sphere for improved oxygen evolution activity of LaCo1-xNixO3 perovskite

The evolution of oxygen evolution reaction (OER) remains a pivotal challenge in the realm of oxygen electrocatalysis. Recently, the proposition of regulating spin states has emerged as a novel avenue for enhancing the efficiency of electrocatalytic reactions. Presently, accurately modulating the metal active center into immediate spin (IS) remains a formidable challenge. Here, our research has achieved a breakthrough in precise spin state control and catalytic performance enhancement of Co3+ through the utilization of Ni-substituted LaCo1-xNixO3 perovskite. This achievement is primarily attributed to the fine regulation of both the secondary coordination sphere (SCS) and primary coordination sphere (PCS), i.e., Co6-y-[Co]-Niy (y = 0–6) and Co-O lengths, respectively. Our findings reveal that LaCo7/9Ni2/9O3 consisted of the SCS (y ≤ 2) with the eg1 fillings of IS Co3+ exhibits an optimal OER activity. Additionally, adjusting the Co-O bond length in PCS to approximately 1.89 Å proves to be more conducive to the transition of Co3+ spin states from high spin (HS) and low spin (LS) to IS. These discoveries present new approach to precisely modulating the spin state, offering promising prospects for the development of high-efficiency OER catalysts.

Aromatic Ethers Induced Electronic Structure Reconstruction on Encapsulated Nickel Catalysts for High-Performance Catalytic Hydrogenation.

Carbon-encapsulated metal (CEM) catalysts effectively address supported metal catalyst instability by protecting the active metal with a shell. However, mass transfer limitations lead to reduced activity for catalytic hydrogenation reaction over most CEM catalysts. Herein, we introduce a dopant strategy aimed at incorporating nickel metal within graphene-like shells (GLS) featuring oxygen-containing functional groups (OFGs). The core of this strategy involves precise control of GLS modification and the demonstrated pivotal influence of aromatic ether linkages (═C-O-C) in GLS for significant enhancement of catalytic performance. The introduction of ═C-O-C into GLS with stability was beneficial to improve the work function of the catalyst and promoted electron transmission from Ni metal core to GLS, further elevating the catalytic activity, based on the Mott-Schottky effect. In addition, the experimental characterization and density functional theory (DFT) calculations showcased that the ═C-O-C reconstructed the electronic state of GLS, imparting it highly specific for the adsorption of hydrogen and para-chloronitrobenzene (p-CNB) to obtain para-chloroaniline (p-CAN) with high selectivity. This work manifested a feasible direction for the precise modulation and design of the OFGs in CEM catalysts to achieve highly efficient catalytic hydrogenation.

Boosting the catalytic activity of Pd-nanocatalysts by anchoring transition metal atoms on carbon supports for formic acid dehydrogenation

Liquid formic acid (FA) dehydrogenation, which needs high-performance catalysts to generate green hydrogen at room temperature, is a promising chemical hydrogen storage technology that can replace fossil fuels in energy-related devices. In this work, a novel nanocatalyst with ultrafine palladium nanoparticles (Pd NPs) immobilized on a transition metal atom-decorated carbon support was synthesized for the dehydrogenation of liquid FA. Via a hydrothermal of glucose and carbonitride with a following Co doping through a heat treatment process, porous carbons with evenly dispersed Co-sites on it were strategically achieved, which could be used as a support for immobilizing Pd NPs. The obtained Pd/NC-Co1% catalyst exhibited much superior catalytic activities to those samples without Co doping on the support (Pd/NC and PdCo1%/NC), showing an impressive turnover frequency of 3045 h−1 at 50 °C for FA dehydrogenation. Other transition metal species such as Fe- and Ni-decorated carbon nanocatalysts also showed an improved catalytic activity for FA dehydrogenation. This work not only provides an efficient method to synthesize nanocatalysts with ultrafine metal NPs but also demonstrates that highly dispersed metal atoms on the support can effectively affect the immobilized NPs, resulting in an enhancement of catalytic performance.