Catalytic Reaction Research Articles

Magnetically induced asymmetry and fuel-propulsion of lipid vesicles containing Fe3O4 micromotors

Artificial micro/nanomotors possess the capability to navigate intricate environments in accordance with a premeditated blueprint. Hybrid-propelled micromotors may present an efficacious approach in addressing scientific research quandaries. In this context, ferric oxide magnetic nanoparticles (Fe3O4 MNPs) are chosen as catalysts to be encapsulated within lipid vesicles (LVs) due to their superior quality and cost-effectiveness. The external magnetic field induces the aggregation of Fe3O4 MNPs within the LVs, resulting in the formation of an asymmetrical structure that promotes the catalytic reaction of hydrogen peroxide, producing oxygen to propel the movement of Fe3O4@LVs micromotors. The magnetic-fuel dual drive enables the Fe3O4@LVs micromotor to move 1.3 times faster than the LVs alone. Additionally, the magnetic field offers the advantage of controlling the direction of motor movement and facilitating retrieval for practical applications. This dual drive micromotor exhibits exceptional stability and reusability in aqueous solutions, underscoring its immense potential for future applications.

Investigation of overall water splitting process on the 1 T/2H-MxCS catalyst via in situ Raman and IR spectroscopy measurement

The decomposition and formation of water molecules determine the protonation and deprotonation processes at the catalyst surface. Detecting interfacial water is particularly challenging because it is located between two condensed phases. Herein, we combine electrochemical in situ Raman and infrared spectroscopy with computational techniques to study the interfacial water on snowflake-like 1 T/2H-xMoS2/Cu2S (1 T/2H-MxCS). The snowflake-like Cu2S prevents the aggregation of modified MoS2 nanoflowers. The 1 T/2H-M0.02CS electrocatalyst exhibits excellence electrochemical performance, with a low overpotential of 59 mV and Tafel slope of 56 mV dec−1. This outstanding property can be ascribed to the interface and the formation of 1 T-MoS2, which not only decreases the activation energy required for the reduction reaction but also provides additional active sites for the catalytic reaction. Density functional theory calculations (DFT), in-situ Raman, and FT-IR spectroscopy were used to further elucidate the mechanism of electrocatalytic performance. This strategy offers new insights into enhancing the electrocatalytic activity of transition metal sulfides and a deep understanding of the HER mechanism.

Nanoporous NiPt alloy by dealloying of amorphous NiZrPt metallic glass for alkaline hydrogen evolution reaction

The development of high-performance and low-cost alkaline hydrogen precipitation catalysts is critical for the large-scale application of hydrogen energy. In this work, the nanoporous alloy catalysts were synthesized by dealloying melt-spun NiZrPt ribbons. The optimal sample after dealloying shows excellent HER performance in alkaline medium, with a small overpotential of 15 mV to deliver 10 mA cm−2 and a low Tafel slope of 20 mV/dec. The material characterization reveals that the incorporation of Ni modulates the electronic structure of Pt. After selective dealloying of Zr and Ni, a Pt-enriched nanoporous structure was formed on the catalyst surface. Meanwhile, the remaining Ni sites acted as synergistic sites to activate the Pt sites, which allowed for better hydrogen adsorption energy and faster kinetics of the catalytic reaction. Besides, the favorable mechanical flexibility of the material makes it potential for self-supporting electrode. This work presents a way to prepare low-Pt efficient catalysts by amorphous alloy dealloying.

In situ formation of inhibitor species through catalytic surface reactions during area-selective atomic layer deposition of TaN.

Small molecule inhibitors (SMIs) have been gaining attention in the field of area-selective atomic layer deposition (ALD) because they can be applied in the vapor-phase. A major challenge for SMIs is that vapor-phase application leads to a disordered inhibitor layer with lower coverage as compared to self-assembled monolayers, SAMs. A lower coverage of SMIs makes achieving high selectivity for area-selective ALD more challenging. To overcome this challenge, mechanistic understanding is required for the formation of SMI layers and the resulting precursor blocking. In this study, reflection adsorption infrared spectroscopy measurements are used to investigate the performance of aniline as an SMI. Our results show that aniline undergoes catalytic surface reactions, such as hydrogenolysis, on a Ru non-growth area at substrate temperatures above 250 °C. At these temperatures, a greatly improved selectivity is observed for area-selective TaN ALD using aniline as an inhibitor. The results suggest that catalytic surface reactions of the SMI play an important role in improving precursor blocking, likely through the formation of a more carbon-rich inhibitor layer. More prominently, catalytic surface reactions can provide a new strategy for forming inhibitor layers that are otherwise very challenging or impossible to form directly through vapor-phase application.

Backstepping synchronization control for four-dimensional chaotic system based on DNA strand displacement

Backstepping control is an important nonlinear control design method, which realizes the control of complex systems by constructing control law step by step, and has significant advantages for dealing with complex nonlinear systems. This article proposes a synchronization technique for four-dimensional chaotic systems using a combination of backstepping control method and DNA strand displacement technology. By relying on theoretical knowledge of DNA molecules, five basic chemical reaction modules such as trigger reaction, reference reaction, catalytic reaction, annihilation reaction and degradation reaction are given to construct a four-dimensional DNA chaotic system. On the basis of the relevant theory of chaotic dynamics, the constructed system is analyzed by Lyapunov exponent diagram and spectral entropy complexity algorithm, and the results come to the conclusion that the system reveals extremely complex and varied dynamic behaviors. Combining DNA strand displacement technology with backstepping control method, four controllers are developed to ensure that the trajectories of two homogeneous chaotic systems are synchronized. The numerical simulation results validate the feasibility and applicability of the proposed method. The method proposed in this paper may provide some references in the field of DNA molecular chaos synchronization control.

Furfural Hydrogenation Over Reduced Pure (LaBO3) and Substituted (LaB0.5B'0.5O3) (B, B': Fe, Co, Ni) Perovskites

AbstractA series of pure and 50 % substituted Fe‐containing (LaFeO3, LaFe0.5Ni0.5O3 and LaFe0.5Co0.5O3) and Co/Ni‐containing (LaCoO3, LaNiO3, and LaCo0.5Ni0.5O3) perovskites were used as precursors to synthesize metallic reduced catalysts to be tested for the liquid hydrogenation of furfural. The catalytic reaction was carried out in a batch reactor at 200 °C and 3.0 MPa of H2 pressure. The calcined perovskites and reduced catalysts were characterized by X‐ray diffraction (XRD), N2 physisorption at 77 K, temperature programmed reduction (H2‐TPR), temperature programmed CO2 and NH3 desorption (CO2‐TPD and NH3‐TPD), Atomic Absorption Spectroscopy (AAS) and X‐ray photoelectron spectroscopy (XPS) techniques. The LaCo0.5Ni0.5O3 reduced catalyst display the highest activity in furfural conversion, which was attributed to a cooperative effect between highly dispersed nickel and cobalt metal nanoparticles after reduction process. The effect of the nature of B‐cation have a high impact on the products selectivity in the hydrogenation of furfural, suggesting that enriched‐Ni metal surface was selectivity to tetrahydrofurfuryl alcohol, meanwhile enriched‐Co metal surface was selective to furfuryl alcohol formation, which was also supported with adsorption mode of furfural over the active sites obtained by quantum calculation.

Predicting and probing the local temperature rise around plasmonic core-shell nanoparticles to study thermally activated processes.

Ultrafast spectroscopy can be used to study dynamic processes on femtosecond to nanosecond timescales, but is typically used for photoinduced processes. Several materials can induce ultrafast temperature rises upon absorption of femtosecond laser pulses, in principle allowing to study thermally activated processes, such as (catalytic) reactions, phase transitions, and conformational changes. Gold-silica core-shell nanoparticles are particularly interesting for this, as they can be used in a wide range of media and are chemically inert. Here we computationally model the temporal and spatial temperature profiles of gold nanoparticles with and without silica shell in liquid and gas media. Fast rises in temperature within tens of picoseconds are always observed. This is fast enough to study many of the aforementioned processes. We also validate our results experimentally using a poly(urethane-urea) exhibiting a temperature-dependent hydrogen bonding network, which shows local temperatures above 90 ◦C are reached on this timescale. Moreover, this experimentally shows the hydrogen bond breaking in such polymers occurs within tens of picoseconds.

Synergistic role of MoS2 in gelation-induced fabrication of graphene oxide films.

Supporting materials for electrocatalysts must exhibit relative chemical inertness to facilitate unimpeded movement of gas, and demonstrate electrical conductivity to promote efficient electron transfer to the catalyst. Conventional catalyst electrodes, such as glassy carbon, carbon cloths, or Ni foam, are commonly employed. However, the challenge lies in the limited stability observed during testing due to the relatively weak adhesion between the catalyst and the electrode. Addressing this limitation is crucial for advancing the stability and performance of catalyst-electrode systems in various applications. Here, we suggest a novel fabrication method for a freestanding conducting film, accomplished through gelation, incorporating 1T-MoS2 and graphene oxide. 1T-MoS2 nanosheets play a crucial role in promoting the reduction of graphene oxide (GO) on the Zn foil. This contribution leads to accelerated film formation and enhanced electrical conductivity in the film. The synergistic effect also enhances the film's stability as catalyst supports. This study provides insights into the effective utilization of MoS2 and graphene oxide in the creating of advanced catalyst support systems with potential applications in diverse catalytic reaction.

Solid-State Oxidation of Alcohols in Gold-Coated Milling Vessels via Direct Mechanocatalysis.

This paper presents a novel approach for the selective oxidation of alcohols to their corresponding aldehydes through direct mechanocatalysis, employing a gold-coated milling vessel as catalyst and air as the oxidation agent. By adjusting milling frequency, media, and duration, high catalytic efficiencies and selectivities are achieved. Remarkably, yields of up to 99% are obtained for specific substrates, with a turnover number (TON) of 8200 and a turnover frequency (TOF) of 0.77 s-1, surpassing existing alternatives. Confirmation of the catalytic reaction indeed occurring on the milling tool surface was achieved through X-ray photoelectron spectroscopy (XPS).

Solid‐State Oxidation of Alcohols in Gold‐Coated Milling Vessels via Direct Mechanocatalysis

This paper presents a novel approach for the selective oxidation of alcohols to their corresponding aldehydes through direct mechanocatalysis, employing a gold‐coated milling vessel as catalyst and air as the oxidation agent. By adjusting milling frequency, media, and duration, high catalytic efficiencies and selectivities are achieved. Remarkably, yields of up to 99% are obtained for specific substrates, with a turnover number (TON) of 8200 and a turnover frequency (TOF) of 0.77 s‐1, surpassing existing alternatives. Confirmation of the catalytic reaction indeed occurring on the milling tool surface was achieved through X‐ray photoelectron spectroscopy (XPS).

Mesoporous SnO2-modified electrode for electrochemical detection of luteolin

Conventional methods like chromatography and spectroscopic analysis have limitations in detecting luteolin. However, electrochemical detection shows promise for reliable analysis. In this study, we compared two different morphologies of SnO2 with the same crystal structure for luteolin detection and found that crystal morphology significantly impacts the catalytic reaction. Compared to SnO2 quantum dots (SnO2 QDs), mesoporous SnO2 (m-SnO2) exhibited a larger specific surface area, providing more active sites for oxidation and reduction reactions. Moreover, m-SnO2 had lower impedance, effectively accelerating charge transfer at the electrode surface. Based on these excellent characteristics, m-SnO2/GCE modified electrode demonstrated outstanding performance in detecting luteolin, achieving a sensitivity of 8.5 μA μM-1, a low limit of 0.19 nM and a wide linear range from 0.5 nM to 1,400 nM. Besides, the m-SnO2/GC electrode displayed excellent consistency, reproducibility, durability, repeatability and specificity. Even three-week exposure to atmospheric conditions, the DPV signal stood at 94.1 % of its original peak current. Those enables its excellent application in practical sample detection. This research enhances our understanding of the influence of material structure and interface on catalytic luteolin detection, providing a theoretical foundation for accurate detection in complex systems. These findings should contribute to the development of more efficient, sensitive, and reliable luteolin sensors.

Based ATP-gating mechanism for detection of alkaline phosphatase in single-glass micropipettes functionalized by three-dimensional DNA network.

The construction of gating system in artificial channels is a cutting-edge research direction in understanding biological process and application sensing. Here, by mimicking the gating system, we report a device that easily synthesized single-glass micropipettes functionalized by three-dimensional (3D) DNA network, which triggers the gating mechanism for the detection of biomolecules. Based on this strategy, the gating mechanism shows that single-glass micropipette assembled 3D DNA network is in the "OFF" state, and after collapsing in the presence of ATP, they are in the "ON" state, at which point they exhibit asymmetric response times. In the "ON" process of the gating mechanism, the ascorbic acid phosphate (AAP) can be encapsulated by a 3D DNA network and released in the presence of adenosine triphosphate (ATP), which initiates a catalyzed cascade reaction under the influence of alkaline phosphatase (ALP). Ultimately, the detection of ALP can be responded to form the fluorescence signal generated by terephthalic acid that has captured hydroxyl radicals, which has a detection range of 0-250mU/mL and a limit of detection of 50mU/mL. This work provides a brand-new way and application direction for research of gating mechanism.

Molecular Electrocatalysis under Finite Diffusive Mass Transport Conditions. An Analytical Approach

AbstractMolecular electrocatalysis has emerged as a crucial branch of molecular electrochemistry, finding applications across various fields such as energy generation, electroanalysis, and electrosynthesis. In recent years, the study of these processes within confined spatial domains, has been increasingly frequent. However, a significant gap exists in the theoretical understanding of the interplay between different kinetics (redox and chemical) and mass transport under these conditions, and how their combined effects influence the electrochemical response. As a first step to address the aforementioned gap, this manuscript presents a theoretical expression for the current‐potential‐time response of a catalytic reaction occurring under finite diffusive conditions. The results indicate that, when the chemical kinetics is not fast, there are significant differences in electrochemical responses due to mass transport influences. Thus, in the case of bounded finite diffusion, a loss of efficiency in the process is observed, resulting in lower currents compared to those corresponding to semi‐infinite diffusive conditions. The validity of well‐known methods, such as the analysis of the current plateau or the foot of the wave under stationary conditions, is discussed. Experimental validation of these results is also provided through the study of the oxidation of Solketal mediated by the oxidation of TEMPO radical.

Opinion — On a New Mechamistic Model Toward the Catalytic Reactions: From Hydrogen Combustion to Fischer-Tropsch Reaction

Mechanism research in catalytic chemistry is both fascinating and confusing, particularly when it comes to solid-state catalysts, the nature of catalytic behaviours has been unidentified so far. For a mechanistic model to be acceptable, it should have an ability to explain all unique aspects of a given catalytic reaction and provide an illuminating explanation to a widely range of catalytic reaction. In our recent reports, a new mechanistic model was suggested for catalytic CO<sub>2</sub> reduction reaction on Cu metal and hydrogen evolution reaction on various transition metals, which provides a reasonable interpretation to both catalytic reactions (from the diversity of product distribution and catalytic behaviour of various metals). Here, it is expected to extend this new mechanistic model to a wider range of catalytic reactions over various catalysts. Such as hydrogen combustion with Cu metal adding, oxidation of SO<sub>2</sub> by O<sub>2</sub> to give SO<sub>3</sub> with NO adding, conversion of CO and NO into CO<sub>2</sub> and N<sub>2</sub> with Ru metal adding, and hydrogeneration of propylene with Pt metal adding. Importantly, this model seems also to pertain to the mechanism of the Fischer-Tropsch (T-F) reaction, i.e. the conversion of CO and H<sub>2</sub> to hydrocarbons, principally a mixture of linear alkanes (including methane) and alkenes, by passage over various heterogeneous transition-metal catalysts (Fe, Co, Ni et.al.).

Structural Engineering of Metal‐Organic Frameworks for Efficient CO2 Reduction Reaction

AbstractMetal‐organic framework (MOF) materials have attracted much attention due to their diverse topological structures, excellent adsorption capacity, and unique physicochemical properties, which hold great promise in catalytic CO2 reduction reaction (CO2RR). However, the original MOFs materials have disadvantages such as poor electrical conductivity, high diffusion barrier and limited accessible catalytic sites, which seriously limit their application in CO2RR. Therefore, many structural engineering strategies have been used to improve the CO2RR performance of the MOFs materials. In this review, we mainly review the four main structure engineering strategies, i. e. crystal engineering, 2D engineering, heterostructure engineering and MOF derivatives engineering, in enhancing the catalytic CO2RR performance of the MOFs. We hope that this review will not only provide insights for the rational design of efficient MOFs materials for the CO2RR, but also stimulate more research work in this field.

Sulfinamide Crossover Reaction.

This study unveils a new catalytic crossover reaction of sulfinamides. Leveraging mild acid catalysis, the reaction demonstrates a high tolerance to structural variations, yielding equimolar products across diverse sulfinamide substrates. Notably, small sulfinamide libraries can be selectively oxidized to sulfonamides, providing a new platform for ligand optimization and discovery in medicinal chemistry. This crossover chemotype provides a new tool for high-throughput experimentation in discovery chemistry.

Photoacoustic Imaging-Guided Self-Adaptive Hyperthermia Supramolecular Cascade Nano-Reactor for Diabetic Periodontal Bone Regeneration.

Commencing with the breakdown of the diabetic osteoimmune microenvironment, multiple pathogenic factors, including hyperglycemia, inflammation, hypoxia, and deleterious cytokines, are conjointly involved in the progression of diabetic periodontal bone regeneration. Based on the challenge of periodontal bone regeneration treatment and the absence of real-time feedback of blood oxygen fluctuation in diabetes mellitus, a novel self-adaptive hyperthermia supramolecular cascade nano-reactor ACFDG is constructed via one-step supramolecular self-assembly strategy to address multiple factors in diabetic periodontal bone regeneration. Hyperthermia supramolecular ACFDG possesses high photothermal conversion efficiency (32.1%), and it can effectively inhibit the vicious cycle of ROS-inflammatory cascade through catalytic cascade reactions, up-regulate the expression of heat shock proteins (HSPs) under near-infrared (NIR) irradiation, which promotes periodontal bone regeneration. Remarkably, ACFDG can provide real-time non-invasive diagnosis of blood oxygen changes during periodontal bone regeneration through photoacoustic (PA) imaging, thus can timely monitor periodontal hypoxia status. In conclusion, this multifunctional supramolecular nano-reactor combined with PA imaging for real-time efficacy monitoring provides important insights into the biological mechanisms of diabetic periodontal bone regeneration and potential clinical theranostics.

On-the-fly kinetic Monte Carlo simulations with neural network potentials for surface diffusion and reaction.

We develop an adaptive scheme in the kinetic Monte Carlo simulations, where the adsorption and activation energies of all elementary steps, including the effects of other adsorbates, are evaluated "on-the-fly" by employing the neural network potentials. The configurations and energies evaluated during the simulations are stored for reuse when the same configurations are sampled in a later step. The present scheme is applied to hydrogen adsorption and diffusion on the Pd(111) and Pt(111) surfaces and the CO oxidation reaction on the Pt(111) surface. The effects of interactions between adsorbates, i.e., adsorbate-adsorbate lateral interactions, are examined in detail by comparing the simulations without considering lateral interactions. This study demonstrates the importance of lateral interactions in surface diffusion and reactions and the potential of our scheme for applications in a wide variety of heterogeneous catalytic reactions.

Enhanced Oxygen Evolution and Zinc-Air Battery Performance via Electronic Spin Modulation in Heterostructured Catalysts.

Beyond optimizing electronic energy levels, the modulation of the electronic spin configuration is an effective strategy, often overlooked, to boost activity and selectivity in a range of catalytic reactions, including the oxygen evolution reaction (OER). This electronic spin modulation is frequently accomplished using external magnetic fields, which makes it impractical for real applications. Herein, spin modulation is achieved by engineering Ni/MnFe2O4 heterojunctions, whose surface is reconstructed into NiOOH/MnFeOOH during the OER. NiOOH/MnFeOOH shows a high spin state of Ni, which regulates the OH- and O2 adsorption energy and enables spin alignment of oxygen intermediates. As a result, NiOOH/MnFeOOH electrocatalysts provide excellent OER performance with an overpotential of 261 mV at 10 mA/cm2. Besides, rechargeable zinc-air batteries based on Ni/MnFe2O4 show a high open circuit potential of 1.56 V and excellent stability for more than 1000 cycles. This outstanding performance is rationalized using density functional theory calculations, which show that the optimal spin state of both Ni active sites and oxygen intermediates facilitates spin-selected charge transport, optimizes the reaction kinetics, and decreases the energy barrier to the evolution of oxygen. This study provides valuable insight into spin polarization modulation by heterojunctions enabling the design of next-generation OER catalysts with boosted performance. This article is protected by copyright. All rights reserved.

Copper‐Catalyzed Dearomative 1,2‐Hydroamination

Catalytic olefin hydroamination reactions are some of the most atom‐economical transformations that bridge readily available starting materials–olefins and high‐value‐added amines. Despite significant advances in this field over the last two decades, the formal hydroamination of nonactivated aromatic compounds remains an unsolved challenge. Herein, we report the extension of olefin hydroamination to aromatic π‐systems by using arenophile‐mediated dearomatization and Cu‐catalysis to perform 1,2‐hydroamination on nonactivated arenes. This strategy was applied to a variety of substituted arenes and heteroarenes to provide general access to structurally complex amines. We conducted DFT calculations to inform mechanistic understanding and rationalize unexpected selectivity trends. Furthermore, we developed a practical, scalable desymmetrization to deliver enantioenriched dearomatized products and enable downstream synthetic applications. We ultimately used this dearomative strategy to efficiently synthesize a collection of densely functionalized small molecules.