Simple Surface Research Articles

Theory and Examples of Catch Bonds.

We discuss slip bonds, catch bonds, and the tug-of-war mechanism using mathematical arguments. The aim is to explain the theoretical tool of molecular potential energy surfaces (PESs). For this, we propose simple 2-dimensional surface models to demonstrate how a molecule under an external force behaves. Examples are selectins. Catch bonds, in particular, are explained in more detail, and they are contrasted to slip bonds. We can support special two-dimensional molecular PESs for E- and L-selectin which allow the catch bond property. We demonstrate that Newton trajectories (NT) are powerful tools to describe these phenomena. NTs form the theoretical background of mechanochemistry.

Acid modification on ZnIn2S4 with sulfur vacancy for highly efficient photocatalytic reduction of Cr(VI)

Anion vacancies caused by acid treatment over photocatalysts have significant influences on photocatalytic processes. In this study, the ZnIn2S4 (denoted as ZIS) nanoflower samples were synthesized using a one-step hydrothermal process and then impregnated with different amounts of nitric acid solutions. The gathered samples were characterized using XRD, SEM, XPS, BET, and EPR, and their photocatalytic reduction activity of Cr(VI) was also studied. Owing to defect structures, the removal of Cr(VI) of sulfur-rich vacancies ZIS-NA-3 reached nearly 100% within 90 min under simulated solar light, which was about 3 times greater than that of the original ZIS. In summary, this study confirmed that nitric acid treatment could form a defect state on the surface of catalysts, enhancing the light absorption range and improving the electron-hole pair separation efficiency. Furthermore, the stability and recycling of the ZIS-NA-3 catalysts were evaluated. This work offered a simple surface modification technique for constructing high-activity photocatalysts so as to achieve the purpose of removal from polluted wastewater containing Cr(VI).

Fast fabricating superhydrophilic PVDF membrane via proanthocyanidins crosslinking at room temperature

Mussels in nature can adhere to the surface of hydrophobic substances by secreting adhesive substances, which has attracted wide attention by coating method for membrane modification. However, complicated processing procedures remain major problems. Here, we proposed a simple, mild and fast surface coating method. Proanthocyanidins (PC) react with 3-aminopropyl triethoxysilane (KH550) under the accelerated action of the oxidant ammonium persulfate (APS) at room temperature to form a polyphenol network. The hydrophilic network coating was constructed on PVDF membrane by surface co-deposition method for 1 h, which could effectively separate different emulsions. The water permeability of modified membrane was 18,271 L∙m−2∙h−1∙bar−1. The permeability for separating isooctane-in-water emulsion arrived at 14,223 L∙m−2∙h−1∙bar−1 and the oil rejection rate was 99.6 %. After ten cycles, the separation flux was 10,836 L∙m−2∙h−1∙bar−1 with the rejection rate of 98.8 %. Modified membranes were soaked in acid and alkali salt solutions of different pH values for 30 days, and maintained good underwater oleophobic performance (>156°). The developed membrane showed excellent separation performance, oleophobic property and acid-base stability. The proposed membrane modification strategy was prospective for efficient separation of oily wastewater.

Two-photon polymerized wetting morphologies for tunable external and internal electrode micropatterning

Numerous existing and emerging microsize technologies operate by utilizing electrical circuits on surfaces and within solid objects, i.e., external and internal electrodes, respectively. While current micropatterning techniques have achieved extensive progress on current systems via pattern resolution and discretization on simple surfaces, the introduction of new applications relies on the complexity of the parts on which these patterns are fabricated. Additionally, many state-of-the-art applications utilize novel materials for functional systems, which further complicates their fabrication. This paper introduces innovative electrode micropatterning and microchannel filling approaches that support complex 3D designs and reduce the number of fabrication steps. The approaches leverage microsize hydrophobic and hydrophilic morphologies fabricated using the two-photon polymerization (2PP) additive manufacturing (AM) process, in conjunction with the target part. Once fabricated, the part is dipped into a conductive solution or other functional liquids, forming patterns on the surfaces and filling the channels based on the pre-designed wetting morphologies. These morphologies incorporate additional structures beyond the conventional hydrophilic and reentrant hydrophobic structures to facilitate the dipping process. This paper demonstrates the efficacy of the tunable electrode micropatterning approach to fabricate various microsystems utilizing 2PP, wetting morphologies, and the developed dipping process.

Mass transport at the bottom of propagating surface waves over a rippled bottom

The sea surface can be described by means of the superposition of many sinusoidal functions. However, quite often the amplitude of each component turns out to be much smaller than its wavelength, and any component evolves independently of the others. Hence, it is common to investigate the dynamics of a simple monochromatic surface wave. Hereinafter, the flow generated by a monochromatic surface wave within the bottom boundary layer over a rippled sea bed is determined by means of the numerical integration of vorticity and continuity equations. The forcing term that drives the fluid motion within the boundary layer is evaluated assuming that the steepness of the monochromatic surface wave is much smaller than one and considering the first term of the Stokes expansion. Even though the irrotational flow that forces the viscous rotational flow near the sea bottom is symmetric with respect to the ripple crests, Blondeaux and Vittori [“A route to chaos in an oscillatory flow: Feigenbaum scenario,” Phys. Fluids A 3(11), 2492–2495 (1991a)] showed that the symmetry of the flow field is broken when the Reynolds number becomes larger than a threshold value Rδ,t1 that depends on the geometrical characteristics of the ripples. The results of Blondeaux and Vittori [“A route to chaos in an oscillatory flow: Feigenbaum scenario,” Phys. Fluids A 3(11), 2492–2495 (1991a)] suggest that, when the Reynolds number is larger than Rδ,t1 but not too far from it, a steady current is also generated. Hereinafter, the steady velocity component is determined as a function of the ripple characteristics.

Numerical simulation and experimental study on seafloor sampling of an anchor-type mud collector based on SPH-FEM coupling method

Marine sediments are important for research in scientific fields such as marine geology, environmental testing of waters, marine biology and seabed resource exploration. Among them, mud miner is an important way to obtain sediments. However, due to the complexity of the marine environment, the seabed sampling operation is a relatively difficult and complicated project. The structural design of the sampler, the operation mode, and the interaction between the sampler and the sediment affect the sampling effect, which leads to the low efficiency of the sampler operation. In order to investigate the main factors affecting the drag force of the sampler during seafloor sampling, this paper takes a simple and portable anchor-type mud collector surface sediment sampler as a study. This paper introduces the mechanical structure and working principle of an anchor-type mud collector, establishes a mechanical model of the mud collector seafloor sampling process and derives the main factors affecting the dragging force: internal friction angle; the horizontal angle of the bi-directional shaft rod; undercut angle [Formula: see text] of bottom cover and dragging speed. A FEM-SPH method based on the coupling of the finite element method (FEM) and the smooth particle hydrodynamics method (SPH) was proposed to simulate the dynamic process of mud collector subsea sampling, and the mechanical data of fine sand and clay were obtained through land-based experiments. Based on the comparison between experimental data and numerical simulation data, the simulation validity of the FEM-SPH method was verified. The results show that the drag force of the clay was greater than that of the fine sand in the experiment of cutting the lower cover of the mud collector into the fine sand and clay, the internal friction angle of the clay is greater than that of the fine sand; with the increase in horizontal inclination angle and the decrease in undercut angle, the dragging force gradually increased; The dragging speed ranged from 0.2 to 0.6 m/s, with an increase in the mass of clay and fine sand collected with increasing speed, resulting in a gradual increase in dragging force. This paper provides a new method to study the force of the mud collector, provides a theoretical method to reduce the intensity and difficulty of manual work in the sampling process and increase the efficiency of sampling.

Characterizing shallow fault zones by integrating profile, borehole and array measurements of seismic data and distributed acoustic sensing

AbstractWithin the framework of the Intercontinental Scientific Drilling Programme (ICDP) ‘Drilling the Eger Rift’ project, five boreholes were drilled in the Vogtland (Germany) and West Bohemia (Czech Republic) regions. Three of them will be used to install high‐frequency three‐dimensional (3D) seismic arrays. The pilot 3D array is located 1.5 km south of Landwüst (Vogtland). The borehole, with a depth of 402 m, was equipped with eight geophones and a fibre optic cable behind the casing used for distributed acoustic sensing (DAS) measurements. The borehole is surrounded by a surface array consisting of 12 seismic stations with an aperture of 400 m. During drilling, a highly fractured zone was detected between 90 m and 165 m depth and interpreted as a possible fault zone. To characterize the fault zone, two vertical seismic profiling (VSP) experiments with drop weight sources at the surface were conducted. The aim of the VSP experiments was to estimate a local 3D seismic velocity tomography including the imaging of the steep fault zone. Our 3D tomography indicates P‐wave velocities between 1500 m/s and 3000 m/s at shallow depths (0–20 m) and higher P‐wave velocities of up to 5000 m/s at greater depths. In addition, the results suggest a NW–SE striking low‐velocity zone (LVZ; characterized by = 1500–3000 m/s), which crosses the borehole at a depth of about 90–165 m. This LVZ is inferred to be a shallow non‐tectonic, steep fault zone with a dip angle of about . The depth and width of the fault zone are supported by logging data as electrical conductivity, core recovery and changes in lithology. In this study, we present an example to test and verify 3D tomography and imaging approaches of shallow non‐tectonic fault zones based on active seismic experiments using simple surface drop weights as sources and borehole chains as well as borehole DAS behind casing as sensors, complemented by seismic stand‐alone surface arrays.

Removal of heavy metal ions from water using nanocellulose-based membranes derived from macroalgae Chara corallina

Chara corallina is a freshwater macroalgae found in aquatic-terrestrial boundary environments. Their cellulose fibers have a crystallinity and biosynthesis similar to those of terrestrial plants. The algal nanocellulose (NC) was prepared through a series of chemical treatments, including alkaline, bleaching, grinding, and acid hydrolysis. The X-ray diffraction (XRD) crystallinity index of nanocellulose was 85.64%. The cellulose nanocrystals are seen in the form of nanorods, and the specific surface area of the sample of NC found was 5.823 m2g-1. The study aimed to test the effectiveness of a nanocellulose composite membrane in removing heavy metal ions, specifically cadmium (Cd), nickel (Ni), and lead (Pb) ions, from an aqueous solution. A vacuum filtration unit was used for the experiment, where up to five filter layers of composite membranes were examined for their ability to remove heavy metal ions. The results showed that the highest removal rates of Cd2+, Ni2+, and Pb2+ ions were 98.20%, 95.15%, and 93.80%, respectively, when using five layers of membranes of NC with the adsorbent dose set at 20 ppm. Cellulose and its derivatives are essential in sustainable technology for wastewater treatment, as they demonstrate exceptional performance in removing various types of pollutants, including heavy metals, dyes, and other pollutants. Cellulose is preferred due to its low cost, biodegradability, eco-friendliness, and simple surface modification.

The Allen–Cahn model with a time-dependent parameter for motion by mean curvature up to the singularity

In this article, we investigate the temporal evolution of arbitrary, simple, closed two-dimensional (2D) and three-dimensional (3D) interfaces under motion driven by mean curvature up to a singularity. To facilitate this investigation, we propose a novel Allen–Cahn (AC) model with a time-dependent interfacial thickness parameter. The original AC equation was developed to model the phase separation of a binary mixture. It is well known that a level set or interface of the solution of the AC equation obeys the dynamics of motion by curvature as the interfacial thickness parameter approaches zero. Generally, it is difficult to find a closed-form analytic solution of the AC equation with any initial condition. Therefore, we need to estimate the solution of the AC equation through computational approaches such as finite difference method (FDM), finite element method (FEM), Fourier-spectral method (FSM), and finite volume method (FVM). Any simple, closed curves and convex surfaces eventually shrink to a point due to motion by mean curvature. Therefore, it becomes necessary to use adaptive mesh techniques to resolve this small size problem. However, even though we use adaptive mesh techniques, we still confront the relatively thick interfacial transition layer when the curves or interfaces become very small. To avoid this problem, we can start with a very small mesh size for a small value of the interfacial parameter, which results in an extremely high computational cost even when using adaptive mesh techniques. To resolve these issues, we present the AC equation with a time-dependent interfacial parameter and develop an adaptive mesh refinement system. To show the superior performance of the proposed mathematical equation and its computational algorithm, we present various numerical experiments and investigate the motion by mean curvature up to the singularity of curves in 2D space and interfaces in 3D space.

Cellulose acetate filter rods tuned by surface engineering modification for typical smoke components adsorption

Abstract A series of filter rods (FRs) with sodium alginate (SA) modification were prepared by a simple one-pot pre-treatment surface modification method for the retention of typical smoke components. The influences of SA on the physico-chemical properties and adsorption behaviors (or retention characteristics) toward FRs were investigated in detail. Based on the results of XRD, BET, and SEM, it can be inferred that SA modification has no influences on compositions and textural properties of FRs. However, surface modification of FR by SA can greatly improve the hydrophilicity of FR, which is crucial for water retention. In situ diffuse Fourier-transform infrared spectroscopy results demonstrate that FR modified by 2 g·L−1 SA presents superior adsorption character for acetone. The differences in the adsorption or retention of water and acetone are ascribed to surface enriched functional groups tuned by surface engineering modification. By contrast, the modification of SA had no obvious effect on the adsorption of CO at room temperature. By contrast, at high temperature, low modification concentration is conducive to the CO2 and CO adsorption. It presents a good perspective for the rational design of new filter materials to reduce the release of harmful components in cigarette smoke.

Determination of Trace Levels of Fenbendazole in Milk, Yogurt and Curd Using Surface Enhanced Raman Spectroscopy (SERS)

A simple, rapid and sensitive surface enhanced Raman spectroscopy (SERS) method is described for the determination of fenbendazole (FBZ) residues in milk and fermented dairy products using yogurt and curd as examples. An extraction method was used to purify the samples from interfering components of the matrix. 5-Nitrothiabendazole, which has similar physicochemical properties, was used as an internal standard. The detection limits for milk were 1.8 nM, 8.8 nM for yogurt, and 13.5 nM for curd. Using partial least squares (PLS), a calibration model was built for the determination of fenbendazole from 100 to 1000 nM. The root-mean square error of calibration (RMSEC) and the root-mean square error of prediction (RMSEP) were 39.4 and 46.5 nM, respectively. The recovery rate was from 97% to 120% and the relative standard deviation was less than 5.0%. The difference between this technique from the widely used liquid chromatography–mass spectrometry (LC–MS) method is in the reduction in time for preliminary sample preparation and significantly lower costs for reagents and consumables. The article examines the influence of order when mixing reagents in a SERS experiment, which is an important tool for optimizing the sensitivity and reproducibility of the method. It was shown for the first time that when various alkaline earth metal chlorides were used for agglomeration of silver nanoparticles (AgNPs), a change in the ratio of peak intensities of the two analytes in the solution was observed. This phenomenon may be used to increase the selectivity of SERS analysis of multicomponent samples.

Efficient production of isomaltulose using engineered Yarrowia lipolytica strain facilitated by non-yeast signal peptide-mediated cell surface display.

Isomaltulose is a 'generally recognized as safe' ingredient and is widely used in the food, pharmaceutical and chemical industries. The exploration and development of efficient technologies is essential for enhancing isomaltulose yield. In the present study, a simple and efficient surface display platform mediated by a non-yeast signal peptide was developed in Yarrowia lipolytica and utilized to efficiently produce isomaltulose from sucrose. We discovered that the signal peptide SP1 of sucrose isomerase from Pantoea dispersa UQ68J (PdSI) could guide SIs anchoring to the cell surface of Y. lipolytica, demonstrating a novel and simple cell surface display strategy. Furthermore, the PdSI expression level was significantly increased through optimizing the promoters and multi-site integrating genes into chromosome. The final strain gained 451.7 g L-1 isomaltulose with a conversion rate of 90.3% and a space-time yield of 50.2 g L-1 h-1. The present study provides an efficient way for manufacturing isomaltulose with a high space-time yield. This heterogenous signal peptide-mediated cell surface display strategy featured with small fusion tag (approximately 2.2 kDa of SP1), absence of enzyme leakage in fermentation broth and ample room for optimization, providing a convenient way to construct whole-cell biocatalysts to synthesize other products and broadening the array of molecular toolboxes accessible for engineering Y. lipolytica. © 2024 Society of Chemical Industry.

Fabrication and Energy Collection of Superhydrophobic Ultra‐Stretchable Film

AbstractSuperhydrophobic surfaces have broad application prospects in various fields due to their special surface wettability. However, most artificial superhydrophobic surfaces are fabricated on rigid substrates or flexible substrates with low deformability, and their performance is difficult to guarantee when a large deformation occurs, hindering further application. Here, a superhydrophobic ultra‐stretchable (SU) film is fabricated by simple template replication and low surface energy modification method using the mixture of vulcanized natural latex (VNR) and silicone emulsion as raw material. The prepared SU film exhibits excellent elasticity and wettability stability and can maintain good superhydrophobicity even after 500% tensile strain. Moreover, droplets dropped on the SU film are bounced in time without any residue, avoiding the accumulation of droplets on the film. Finally, a magnetoelectric generator composed of a SU film and an electromagnetic system are developed to realize the efficient utilization and conversion of droplet energy via droplet impacting and bouncing behavior.

An ultra-sensitive biosensor based on surface plasmon resonance and weak value amplification.

An ultra-sensitive phase plasmonic sensor combined with weak value amplification is proposed for the detection of IgG, as a model analyte. Phase detection is accomplished by self-interference between the p-polarization and the s-polarization of the light. With the principles of weak value amplification, a phase compensator is used to modulate the coupling strength and enhance the refractive index sensitivity of the system. On a simple Au-coated prism-coupled surface plasmon resonance (SPR) structure, the scheme, called WMSPR, achieves a refractive index sensitivity of 4.737 × 104 nm/RIU, which is about three times higher than that of the conventional phase-based approach. The proposed WMSPR biosensor gives great characteristics with a high resolution of 6.333 × 10-8 RIU and a low limit of detection (LOD) of 5.3ng/mL. The results yield a great scope to promote the optimization of other SPR biosensors for high sensitivity.

Pool boiling heat transfer of Novec 649 on sandblasted surfaces

Pool boiling represents a potentially efficient mechanism for thermal management of power electronic components. The present study investigates pool boiling heat transfer using Novec 649 on copper substrates with varying surfaces. Sandblasting, which is a relatively simple surface modification technique, has been used to obtain different copper surface roughness levels ranging from 0.1 µm to 9 µm arithmetic mean surface roughness values. The effects of surface modifications and orientation on boiling heat transfer coefficient (HTC), and critical heat flux (CHF), of Novec 649 have been experimentally investigated by performing pool boiling experiments at atmospheric pressure and saturation pool temperature. The experimental results showed that the size and orientation of the boiling surface do not have a significant impact on the CHF, whilst the HTC improves in the nucleate boiling regime with vertical orientation. In addition, for the range of surface roughness investigated improvements of ∼3X and ∼1.5X in HTC and CHF, respectively, were found relative to the original smooth surface. The HTC in the film boiling regime relative to the nucleate boiling regime was also quantified and found to be ∼20X for our geometries.

Simple surface modification of barium sulfate for improving the interface of polymer composites and its x‐ray shielding properties

AbstractRadiation shielding materials have been researched using Pb and metal oxide particles, and composites of resin and barium sulfate (BaSO4) have been reported. In addition, multiwalled carbon nanotubes (MWCNTs) have often been used as a nanomaterial to improve the mechanical strength of resin–BaSO4 composites. The literature includes no examples of these two materials—BaSO4 and MWCNTs—being used at the interface of composites. We effectively modified the surface of BaSO4 by a simple process involving strong electrostatic interaction between positively charged barium and negatively charged functional groups on the MWCNT surface. The process is simple and can form large amounts of MWCNTs that coat BaSO4 surfaces. As a result, MWCNTs remained on the BaSO4 surface even after the MWCNT‐coated BaSO4 was washed with a solvent and subjected to melt mixing. The physical anchoring of MWCNTs onto the BaSO4 surface improved the interfacial adhesion and mechanical properties of the resultant composites. The originality of this research is that MWCNTs can be coated onto the surface by only electrostatic interaction without using a polymer adhesive. In addition, the x‐ray shielding performance of the MWCNT‐containing composites was the same as that of composites prepared without the MWCNTs.Highlights MWCNTs were coated onto the surface of BaSO4 by electrostatic interaction. Interfacial adhesion of PS composites was improved by coating MWCNTs. The MWCNTs did not affect the x‐ray shielding performance.

Surface active functional groups enhanced PET non‐woven fabric for the filtering of harmful substances in smoke

AbstractHarmful components in cigarette smoke, such as nicotine, tar, and organic particulate matter, are the primary culprits behind lung diseases. While conventional filter materials based on cellulose, carbon, and molecular sieves exhibit commendable filtration capabilities, their high cost restricts their widespread applications. Based on this, the authors aim to prepare PET‐based filter materials with good adsorption properties through a simple surface functionalisation strategy. The adsorption performance of the PET‐based non‐woven fabric was enhanced by the introduction of sodium alginate (SA). The gas adsorption experiments results reveal that SA‐modified PET (SA‐PET) exhibits significantly improved filtration efficiency for nicotine, tar, and total particulate matter—increasing by 27.1%, 26.2%, and 21.3%, respectively. Moreover, SA‐PET exhibits more odour control ability than traditional activated carbon‐based filter materials. These results prove that surface‐functionalised SA‐PET has better filtration performance for harmful substances in smoke and provides a new strategy for the design of high‐performance filtration materials.

Strontium-loaded 3D intramedullary nail titanium implant for critical-sized femoral defect in rabbits.

The treatment of critical-sized bone defects has long been a major problem for surgeons. In this study, an intramedullary nail shaped three-dimensional (3D)-printed porous titanium implant that is capable of releasing strontium ions was developed through a simple and cost-effective surface modification technique. The feasibility of this implant as a stand-alone solution was evaluated using a rabbit's segmental diaphyseal as a defect model. The strontium-loaded implant exhibited a favorable environment for cell adhesion, and mechanical properties that were commensurate with those of a rabbit's cortical bone. Radiographic, biomechanical, and histological analyses revealed a significantly higher amount of bone ingrowth and superior bone-bonding strength in the strontium-loaded implant when compared to an untreated porous titanium implant. Furthermore, one-year histological observations revealed that the strontium-loaded implant preserved the native-like diaphyseal bone structure without failure. These findings suggest that strontium-releasing 3D-printed titanium implants have the clinical potential to induce the early and efficient repair of critical-sized, load-bearing bone defects.

Building a robust surface structure toward stable ultrahigh-nickel cathodes

Ni-rich cathodes especially with Ni content over 90 % are promising next-generation cathode materials for advanced high energy lithium − ion batteries. However, in comparison with Ni ≤ 80 % Ni-rich cathodes, these ultrahigh Ni-rich materials face more severe challenges in terms of harmful H2 − H3 phase transformations and structural degradation during cycling. Herein, we present a robust surface structure composted of defect-rich disordered structures and LiF/Li2SiO3 coating for stabilizing the ultrahigh Ni-rich cathode LiNi0.96Co0.03Mn0.01O2 (NCM96) by modification with (NH4)2SiF6. The surface disordered structures including Li/TM mixing, spinel, and rock salt structure play a crucial role in inhibiting the irreversible H2-H3 phase transition and reducing lattice volume changes by lattice coherence effect. Moreover, the disordered surface in collaboration with the co-coating restrains the rapid growth of surface rock salt phase into the bulk, enhancing structural stability. The modified sample NSF-0.5 delivers a capacity of 238 mAh/g at 0.1C and maintains a capacity retention of 88.5 % at 0.5C after 100 cycles in half cell as well as 82.3 % at 1C after 300 cycles in full cell, significantly superior to the NCM96. The findings provide a simple and cost-effective surface modification strategy to enhance the structural stability and electrochemical performance of ultrahigh nickel cathodes for high-energy density LIBs.

Boosting N[tbnd]N tri-bond activation and NH3 generation rate through simple surface Ag modification

NH3 photosynthesis from nitrogen remains a big challenge due to the extreme difficulty for the activation of NN bond. In this work, Ag-modified MoO3·0.55 H2O nanorods (named as Ag@Mo) are prepared by a simple photoreduction method. Under visible light (λ ≥ 420 nm) for 60 min, the NH3 yield over 2%Ag@Mo (molar ratio of Ag to MoO3·0.55 H2O) reaches 242.0 μmol·gcat−1, which is about 2.8 times higher than MoO3·0.55 H2O under the same conditions. The effect of Ag modification on photocatalytic ammonia synthesis is explored through experiments and theoretical calculations. The excellent photocatalytic performance is mainly attributed to the localized surface plasmon resonance effect of Ag and the successful construction of Mott-Schottky junction, which improves light utilization efficiency and reduces carrier recombination efficiency, respectively. Moreover, density functional theory calculations theoretically prove that over Ag@Mo, Ag provides new adsorption sites, and the NN tri-bond length is elongated by about 16.2%, confirming that Ag modification obviously promotes the activation of NN tri-bond. The ammonia generation rate is obviously higher than the previously reported results.