Catalytic Activity Research Articles

The Rational Design of Atomically Dispersed Catalysts via Spin Manipulation.

The catalytic activity of transition-metal-based atomically dispersed catalysts is closely related to the spin states. Manipulating the spin state of metal active centers could directly adjust the d orbital occupancy and optimize the adsorption behavior and electron transfer of the intermediates and transition metals, which would enhance the catalytic activity. We summarize the means of manipulating spin states and the spin-related catalytic descriptors. In future work, we will build a quantifiable and accurate prediction intelligent model through artificial intelligence (AI) and machine learning tools. Furthermore, we will develop new spin regulation methods to carry out the directional regulation of atomically dispersed catalysts through this model, providing new insight into the rational design of transition-metal-based atomically dispersed catalysts through spin manipulation.

Protector-free, non-plasmonic silver quantum clusters by femtosecond pulse laser irradiation: in situ binding on nanocellulose filaments for improved catalytic activity and cycling performance.

This study introduces a new, facile method to synthesize silver clusters from aqueous silver ion solution by using high intensity femtosecond pulse laser irradiation. The particles obtained in the absence of reducing or capping agents are 1-17 nm in size and presented quantum properties, as characterized by fluorescence, but did not exhibit plasmon signals, which is not a common characteristic of conventional silver nanoparticles. In a further development, small silver quantum clusters (∼1 nm) were bound in situ to wet-spun filaments of cellulose nanofibrils by pulsed laser irradiation. The obtained hybrid filaments as well as free silver quantum clusters revealed a catalytic activity remarkably higher than that of free gold quantum clusters; moreover, the hybrid filaments were found to show improved stability and cycling performance for silver-based catalysis. The present results indicate the potential of femtosecond laser irradiation to generate clusters as well as hybrid systems with excellent performance and reactivity.

Propelling gold nanozymes: catalytic activity and biosensing applications.

Recently, gold nanomaterials have been rapidly developed owing to their high stability, good biocompatibility, and multifunctionality. The unique catalytic activity of gold nanomaterials has driven the emergence of the concept for a"gold nanozyme." Understanding the characteristics of gold nanozymes is crucial for improving their catalytic performance as well as expanding their applications. In this review, we provide an overview of the intrinsic enzyme-like activities of gold nanozymes, including peroxidase-, catalase-, superoxide dismutase-, and glucose oxidase-like activities, and the catalytic mechanisms involved. In addition, strategies for modulating the catalytic activity of gold nanozymesand theirapplications in biosensing were discussed in detail. Moreover, we highlight the current challenges of gold nanozymes and look forward to attracting more attention for propelling the developments in this field.

Asymmetric Potential Model of Two-Dimensional Imine Covalent Organic Frameworks with Enhanced Quantum Efficiency for Photocatalytic Water Splitting.

Two-dimensional (2D) covalent organic frameworks (COFs) assembled using building blocks have been widely employed in photocatalysis due to their customizable optoelectronic characteristics and porous structure, which facilitate charge carrier and mass movement. Nevertheless, the development of COF photocatalysts encounters a continuous obstacle in enhancing the efficiency of photocatalysis, impeded by a limited comprehension of the orbital interaction between molecular fragments and linkers. In this study, we present a model that examines the interaction between molecular fragments in an imine-based COF at the frontier molecular orbital level, enabling us to comprehend the impact of manipulating linkers on light adsorption, exciton efficiency, and catalytic activity. Our findings demonstrate that altering the connecting orientation of 14 R-C=N-R imine linkers in 2D COFs can enhance solar-to-hydrogen (STH) efficiency under visible light from 2.76% to 4.24%. This research has the potential to provide a valuable model for refining photocatalysts with enhanced photocatalytic performance.

Exploring Flower-Structured Bifunctional VCu Layered Double Hydroxide and its Nanohybrid with g-C3N4for Electrochemical and Photoelectrochemical Seawater Electrolysis.

Seawater electrolysis holds great promise for sustainable green hydrogen generation, but its implementation is hindered by high energy consumption and electrode degradation. Two dimensional (2D) layered double hydroxide (LDH) exhibits remarkable stability, high catalytic activity, and excellent corrosion resistance in the harsh electrolytic environment. The synergistic effect between LDH and seawater ions enhances the oxygen evolution reaction, enabling efficient and sustainable green hydrogen generation. Here, we report a synthesis of low cost, novel 2D Vanadium Copper (VCu) LDH first time in the series of LDH's as a highly efficient bifunctional electrocatalyst. The electrochemical (EC) and photoelectrochemical (PEC) study of VCu LDH and VCu LDH/Graphite Carbon Nitride (g-C3N4) nanohybrid was performed in 0.5 M H2SO4 (acidic), 1 M KOH (basic), 0.5 M NaCl (artificial seawater), 0.5 M NaCl + 1 M KOH (artificial alkaline seawater), real seawater and 1 M KOH + real seawater (alkaline real seawater) electrolyte medium. It was found that VCu LDH shows a remarkable lower overpotential of 72 mV hydrogen evolution reaction (HER) and 254 mV oxygen evolution reaction (OER) at current density of 10 mA/cm2 under alkaline real seawater electrolysis exhibiting bifunctional activity and also showing better stability.

Enhanced Activity and Selectivity for Nitrogen Reduction Reaction in Electrode-based Heterostructures: A DFT Computational Study.

Developing sustainable and efficient catalysts for ammonia synthesis from atmospheric molecular N2 under ambient conditions presents a significant 21st-century challenge. Two-dimensional heterostructures, particularly single-atom catalysts (SACs) supported on two-dimensional materials, have emerged as a promising avenue due to their remarkable catalytic activity and selectivity. Electrides, characterized by an abundance of free electrons and high surface activity, have attracted substantial attention in this context. Through density functional theory (DFT) calculations, this study proposes electride-graphene heterostructures (EGHS) as catalysts to effectively regulate charge distribution at the catalytic center, facilitating the optimization of catalytic performance. The EGHS model addresses challenges related to excessive adsorbate binding, mitigating electron transfer compared to electride monolayer adsorption. This novel approach utilizes heterogeneous heterostructures to finely tune the catalytic site, optimizing electron input for enhanced catalysis.Based on the optimized charge transfer for N2 activation, the Cr-doped EGHS (Cr@EGHS) exhibits a promising performance in the nitrogen reduction reaction, leading to, a relatively low limiting potential of -0.85 V and high selectivity. The hypothesis charge transfer depend on N2 activation is further supported by modulating the distance between component layers of heterostructure. These findings contribute to design principles for 2D heterostructure catalysts and offer a reference for experimental synthesis.

In-Depth Understanding of the Oxidative Compatibility of Volatile Organic Compounds with Mn2O3 and Pt-Loaded Catalysts.

Designing suitable catalysts for efficiently degrading volatile organic compounds (VOCs) is a great challenge due to the distinct variety and nature of VOCs. Herein, the suitability of different typical VOCs (toluene and acetone) over Pt-based catalysts and Mn2O3 was investigated carefully. The activity of Mn2O3 was inferior to Pt-loaded catalysts in toluene oxidation but showed superior ability for destroying acetone, while Pt loading could boost the catalytic activity of Mn2O3 for both acetone and toluene. This suitability could be determined by the physicochemical properties of the catalysts and the structure of the VOC since toluene destruction activity is highly reliant on Pt0 in the metallic state and linearly correlated with the amount of surface reactive oxygen species (Oads), while the crucial factor that affects acetone oxidation is the mobility of lattice oxygen (Olat). The Pt/Mn2O3 catalyst shows highly active Pt-O-Mn interfacial sites, favoring the generation of Oads and promoting Mn-Olat mobility, leading to its excellent performance. Therefore, the design of abundant active sites is an effective means of developing highly adaptive catalysts for the oxidation of different VOCs.

Hydrolysis of Nerve Agent Simulants Accelerated by Stimuli-Responsive Dinuclear Catalysts.

The ability to control the catalytic activity of enzymes in chemical transformations is essential for the design and development of artificial catalysts. Herein, we report the synthesis and characterization of functional ligands featuring two 1,4,7,10-tetraazacyclododecane units linked by an azobenzene group and their corresponding dinuclear Zn(II) complexes. We show that the configuration switching (E/Z) of the azobenzene spacer in the ligands and their dinuclear Zn(II) complexes is reversibly controlled by irradiation with UV and visible light. The Zn(II)-metal complexes are light-responsive catalysts for the hydrolytic cleavage of nerve agent simulants, i.e., p-nitrophenyl diphenyl phosphate and methyl paraoxon. The catalytic activity of the Z-isomers of the dinuclear Zn(II) complexes outperformed that of the E-counterparts. Moreover, combining the less active E-isomers with gold nanoparticles induced an enhancement in the hydrolysis rate of p-nitrophenyl diphenyl phosphate. Kinetic analysis has shown that the catalytic site appears to involve a single metal ion. We explain our results by considering the different desolvation effects occurring in the catalyst's configurations in the solution and the catalytic systems involving gold nanoparticles.

Catalytic activity of Ni–Cr–Fe–Mo porous materials for hydrogen evolution reaction in alkaline media

The hydrogen evolution reaction (HER) based on water electrolysis represents an ideal approach for hydrogen production. The advancement of highly active non-precious metal catalysts holds paramount importance. This research employed powder metallurgy sintering to prepare Ni–Cr–Fe and Ni–Cr–Fe–Mo porous materials. It investigated the impact of Mo doping and sintering temperature on the catalytic activity and microstructural influence of hydrogen evolution materials. Furthermore, the materials' electrochemical performance and long-term stability in 6 mol/L KOH were examined. In complicated systems, the current work provides a feasible method for producing hydrogen from Ni–Cr–Fe–Mo porous materials in a strong alkali environment. The results exhibited that when Mo content is 5% and the sintering temperature is 800 °C, the porosity of Ni–Cr–Fe–Mo porous materials is up to 39.9% and the catalytic activity is up to 97%. At the same time, the current density decays to 7.1% after 1000 cycles of electrolysis and shows good HER stability after 48 h. The enhanced catalytic activity for hydrogen evolution emanated from the positive synergy among the transition metal elements.

Transcriptome analysis reveals the molecular mechanisms underlying the enhancement of salt-tolerance in Melia azedarach under salinity stress

Melia azedarach demonstrates strong salt tolerance and thrives in harsh saline soil conditions, but the underlying mechanisms are poorly understood. In this study, we analyzed gene expression under low, medium, and high salinity conditions to gain a deeper understanding of adaptation mechanisms of M. azedarach under salt stress. The GO (gene ontology) analysis unveiled a prominent trend: as salt stress intensified, a greater number of differentially expressed genes (DEGs) became enriched in categories related to metabolic processes, catalytic activities, and membrane components. Through the analysis of the category GO:0009651 (response to salt stress), we identified four key candidate genes (CBL7, SAPK10, EDL3, and AKT1) that play a pivotal role in salt stress responses. Furthermore, the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis revealed that DEGs were significantly enriched in the plant hormone signaling pathways and starch and sucrose metabolism under both medium and high salt exposure in comparison to low salt conditions. Notably, genes involved in JAZ and MYC2 in the jasmonic acid (JA) metabolic pathway were markedly upregulated in response to high salt stress. This study offers valuable insights into the molecular mechanisms underlying M. azedarach salt tolerance and identifies potential candidate genes for enhancing salt tolerance in M. azedarach.

Convenient construction of electrocatalysts via combustion-assisted corrosion engineering for efficient water oxidation

Developing an efficient strategy for the universal synthesis of electrocatalysts is crucial for advancing the industrialization of water splitting, yet it remains a significant challenge. In this study, we propose combustion-assisted corrosion engineering as a rapid method to fabricate electrocatalysts for the oxygen evolution reaction (OER) within seconds. By utilizing a three-dimensional framework composed of nickel foam and the unique structure of the active species, we enable swift electrolyte diffusion and gas release. Consequently, the optimized S–NiO/NF exhibits remarkable OER catalytic activity, requiring a low overpotential of 236 mV to achieve a current density of 50 mA cm−2 in 1.0 M KOH solution. Notably, the reconfiguration during the OER process leads to the formation of actual catalytic active species, enhancing the number of active centers and thereby improving the catalyst's performance. This research presents a versatile method for industrially fabricating non-noble metal self-supporting electrodes with high efficiency, offering a practical solution for energy conversion and storage.

A role for the C. elegans Argonaute protein CSR-1 in small nuclear RNA 3' processing.

The Integrator is a multi-subunit protein complex that catalyzes the maturation of snRNA transcripts via 3' cleavage, a step required for snRNA incorporation with snRNP for spliceosome biogenesis. Here we developed a GFP based in vivo snRNA misprocessing reporter as a readout of Integrator function and performed a genome-wide RNAi screen for Integrator regulators. We found that loss of the Argonaute encoding csr-1 gene resulted in widespread 3' misprocessing of snRNA transcripts that is accompanied by a significant increase in alternative splicing. Loss of the csr-1 gene down-regulates the germline expression of Integrator subunits 4 and 6 and is accompanied by a reduced protein translation efficiency of multiple Integrator catalytic and non-catalytic subunits. Through isoform and motif mutant analysis, we determined that CSR-1's effect on snRNA processing is dependent on its catalytic slicer activity but does not involve the CSR-1a isoform. Moreover, mRNA-sequencing revealed high similarity in the transcriptome profile between csr-1 and Integrator subunit knockdown via RNAi. Together, our findings reveal CSR-1 as a new regulator of the Integrator complex and implicate a novel role of this Argonaute protein in snRNA 3' processing.

Cu/Co Bimetallic Carbon Catalyst as a Highly Efficient Promoter for Reactive Dyes Degradation with PMS.

The synergistic effect between bimetallic catalysts has been confirmed as an effective method for activating persulfate (PMS). Therefore, we immobilized copper-cobalt on chitosan to prepare bimetallic carbon catalysts for PMS activation and degradation of reactive dyes. Experimental results demonstrate that the CuCo-CTs/PMS catalytic degradation system exhibits excellent degradation performance toward various types of reactive dyes (e.g., Ethyl violet, Chlortalidone, and Di chlorotriazine), with degradation rates reaching 90% within 30 min. CuCo-CTs exhibit high catalytic activity over a wide pH range of 3-11 at room temperature and under static conditions, degrading over 92% of RV5 within 60 min. ultraviolet-visible (UV-vis) spectroscopy and color changes in the dye solution confirm the effective degradation of RV5, with a degradation rate of 97.2% within 10 min. Additionally, CuCo-CTs demonstrate good stability and reusability, maintaining a degradation rate of 92.8% after eight cycles. Kinetic studies indicate that the degradation follows pseudo-first-order kinetics. Furthermore, based on the results of radical scavenging experiments, the catalytic degradation mechanism of the dye involves both radical and nonradical pathways, with 1O2 identified as the primary active species. This study provides insights and experimental evidence for the application of persulfate oxidation in the treatment of dyeing wastewater.

Defect-enabling zirconium-based metal-organic frameworks for energy and environmental remediation applications.

This comprehensive review explores the diverse applications of defective zirconium-based metal-organic frameworks (Zr-MOFs) in energy and environmental remediation. Zr-MOFs have gained significant attention due to their unique properties, and deliberate introduction of defects further enhances their functionality. The review encompasses several areas where defective Zr-MOFs exhibit promise, including environmental remediation, detoxification of chemical warfare agents, photocatalytic energy conversions, and electrochemical applications. Defects play a pivotal role by creating open sites within the framework, facilitating effective adsorption and remediation of pollutants. They also contribute to the catalytic activity of Zr-MOFs, enabling efficient energy conversion processes such as hydrogen production and CO2 reduction. The review underscores the importance of defect manipulation, including control over their distribution and type, to optimize the performance of Zr-MOFs. Through tailored defect engineering and precise selection of functional groups, researchers can enhance the selectivity and efficiency of Zr-MOFs for specific applications. Additionally, pore size manipulation influences the adsorption capacity and transport properties of Zr-MOFs, further expanding their potential in environmental remediation and energy conversion. Defective Zr-MOFs exhibit remarkable stability and synthetic versatility, making them suitable for diverse environmental conditions and allowing for the introduction of missing linkers, cluster defects, or post-synthetic modifications to precisely tailor their properties. Overall, this review highlights the promising prospects of defective Zr-MOFs in addressing energy and environmental challenges, positioning them as versatile tools for sustainable solutions and paving the way for advancements in various sectors toward a cleaner and more sustainable future.

Arg1 from Cryptococcus neoformans lacks PI3 kinase activity and conveys virulence roles via its IP3-4 kinase activity.

Inositol tris/tetrakis phosphate kinases (IP3-4K) in the human fungal priority pathogens, Cryptococcus neoformans (CnArg1) and Candida albicans (CaIpk2), convey numerous virulence functions, yet it is not known whether the IP3-4K catalytic activity or a scaffolding role is responsible. We therefore generated a C. neoformans strain with a non-functional kinase, referred to as the dead-kinase (dk) CnArg1 strain (dkArg1). We verified that, although dkARG1 cDNA cloned from this strain produced a protein with the expected molecular weight, dkArg1 was catalytically inactive with no IP3-4K activity. Using recombinant CnArg1 and CaIpk2, we confirmed that, unlike the IP3-4K homologs in humans and Saccharomyces cerevisiae, CnArg1 and CaIpk2 do not phosphorylate the lipid-based substrate, phosphatidylinositol 4,5-bisphosphate, and therefore do not function as class I PI3Ks. Inositol polyphosphate profiling using capillary electrophoresis-electrospray ionization-mass spectrometry revealed that IP3 conversion is blocked in the dkArg1 and ARG1 deletion (Cnarg1Δ) strains and that 1-IP7 and a recently discovered isomer (4/6-IP7) are made by wild-type C. neoformans. Importantly, the dkArg1 and Cnarg1Δ strains had similar virulence defects, including suppressed growth at 37°C, melanization, capsule production, and phosphate starvation response, and were avirulent in an insect model, confirming that virulence is dependent on IP3-4K catalytic activity. Our data also implicate the dkArg1 scaffold in transcriptional regulation of arginine metabolism but via a different mechanism to S. cerevisiae since CnArg1 is dispensable for growth on different nitrogen sources. IP3-4K catalytic activity therefore plays a dominant role in fungal virulence, and IPK pathway function has diverged in fungal pathogens.IMPORTANCEThe World Health Organization has emphasized the urgent need for global action in tackling the high morbidity and mortality rates stemming from invasive fungal infections, which are exacerbated by the limited variety and compromised effectiveness of available drug classes. Fungal IP3-4K is a promising target for new therapy, as it is critical for promoting virulence of the human fungal priority pathogens, Cryptococcus neoformans and Candida albicans, and impacts numerous functions, including cell wall integrity. This contrasts to current therapies, which only target a single function. IP3-4K enzymes exert their effect through their inositol polyphosphate products or via the protein scaffold. Here, we confirm that the IP3-4K catalytic activity of CnArg1 promotes all virulence traits in C. neoformans that are attenuated by ARG1 deletion, reinforcing our ongoing efforts to find inositol polyphosphate effector proteins and to create inhibitors targeting the IP3-4K catalytic site, as a new antifungal drug class.

Vitamin B1-based thiazol-2-ylidene-Ru(II) complexes: recyclable transfer hydrogenation catalysts in water.

The [(p-cymene)RuCl(κ2C,N-{CNHC-NH})]+X- (CNHC = thiazol-2-ylidene) complexes with a bidentate ligand (2: X = Cl and 3: X = PF6) were prepared by a one-pot reaction of vitamin B1 (VB1, 1), Ag2O and [(p-cymene)RuCl2]2. In the complexes, VB1 coordinates through C2 and the exocyclic N in the imino form with the κ2-(C,N) coordination mode. The complexes 2 and 3 are stable in the solid state, but slowly release p-cymene in solution. Furthermore, upon heating in polar solvents, 2 or 3 can be converted by ligand exchange reactions to produce [(L)3RuCl(κ2C,N-{CNHC-NH})]+PF6- (4: L = py).Robustness was improved remarkably for 4. The complex 4 is stable in the solid state and in solution. The complexes 2-4 have been identified by 1H and 13C{1H} 2D NMR spectroscopy and 2 and 4 were studied by X-ray crystallography. In an effort to develop a recyclable catalyst in water, 2-4 were evaluated for TH of ketones and aldehydes with an azeotropic mixture of HCOOH/Et3N in water. The complexes 3 and 4 exhibited very good catalytic activity and 4 could be reused nine times without significant loss of activity, giving a high turnover frequency (TOF50%(h-1) = 1286).

Harnessing N-Heterocyclic Carbene Catalytic Activity into Stereoselective Synthesis of Chiral Cyclophanes

Harnessing N-Heterocyclic Carbene Catalytic Activity into Stereoselective Synthesis of Chiral Cyclophanes

Crystal Facet Controlled Metal-Support Interaction in Uricase Mimics for Highly Efficient Hyperuricemia Treatment.

The effect of strong metal-support interaction (SMSI) has never been systematically studied in the field of nanozyme-based catalysis before. Herein, by coupling two different Pd crystal facets with MnO2, i.e., (100) by Pd cube (Pdc) and (111) by Pd icosahedron (Pdi), we observed the reconstruction of Pd atomic structure within the Pd-MnO2 interface, with the reconstructed Pdc (100) facet more disordered than Pdi (111), verifying the existence of SMSI in such coupled system. The rearranged Pd atoms in the interface resulted in enhanced uricase-like catalytic activity, with Pdc@MnO2 demonstrating the best catalytic performance. Theoretical calculations suggested that a more disordered Pd interface led to stronger interactions with intermediates during the uricolytic process. In vitro cell experiments and in vivo therapy results demonstrated excellent biocompatibility, therapeutic effect, and biosafety for their potential hyperuricemia treatment. Our work provides a brand-new perspective for the design of highly efficient uricase-mimic catalysts.

Sustainable nanomaterials' role in green supply chains and environmental sustainability

The review explores the pivotal role of sustainable nanomaterials in promoting green supply chains and advancing environmental sustainability. Nanotechnology has emerged as a promising field for developing innovative materials with enhanced properties and reduced environmental impacts. Sustainable nanomaterials, characterized by their eco-friendly synthesis methods, biodegradability, and low toxicity, offer transformative opportunities for enhancing the sustainability of supply chains across diverse industries. This review examines the potential applications of sustainable nanomaterials in green supply chains, encompassing areas such as renewable energy, water purification, waste management, and sustainable packaging. By leveraging the unique properties of nanomaterials, such as high surface area-to-volume ratio, catalytic activity, and tunable properties, businesses can develop sustainable solutions to address pressing environmental challenges. Case studies and examples highlight successful integration of sustainable nanomaterials into supply chain practices, showcasing their ability to reduce resource consumption, minimize waste generation, and mitigate environmental impacts. The review also discusses challenges and considerations associated with the adoption of sustainable nanomaterials, including regulatory compliance, risk assessment, and ethical considerations. Strategies for promoting responsible nanotechnology practices and fostering collaboration among stakeholders are proposed, emphasizing the importance of interdisciplinary approaches and stakeholder engagement in achieving sustainable supply chain goals. In conclusion, the integration of sustainable nanomaterials into green supply chains holds immense potential for driving environmental sustainability, innovation, and long-term prosperity. Keywords: Sustainable Nanomaterials, Green Supply Chains, Environmental Sustainability, Circular Economy, Nanotechnology, Supply Chain Optimization

Development of catalytic zero-valent iron incorporated PAN catalytic film for efficient degradation of organic matters

Catalytic films work well in degradation of organic matters. However, catalytic activity and stability of films are challenging factors. A nanoscale zero-valent iron (NZVI) incorporated porous PAN fiber (Fe-PAN) film was thus developed through a one-step cryogenic auxiliary electrospinning method. The Fe-PAN film overcame the problem in the traditional multistep preparation process. The excellent intrinsic properties of the polymer in the film were maintained. It exhibited high catalytic activity (> 95% conversion in just 4 min) and excellent stability and reusability, due to the synergistic interaction between PAN and NZVI. The degradation process was optimized by the Box-Behnken design, leading to the optimal condition: pH = 2.8, temperature = 56 °C, and oxidant concentration = 4.2 mmol/L. The degradation followed the 2nd order kinetic equation and was due to the reactions by ·OH and O2-· radicals. This study demonstrates the great potentials of the Fe-PAN film for industrial applications.