Bonded Carbon Atoms Research Articles

Mechanical Integrity and Reinforcement Efficiency of Graphene Grown on Liquid Copper by Chemical Vapor Deposition

AbstractGraphene is a perfect 2D crystal of covalently bonded carbon atoms and constitutes the building block for all graphitic structures. Its superior properties make it an attractive material for a variety of technological applications. However, mass production does not meet the initial expectations. Chemical Vapor Deposition (CVD) is currently the only available method for large‐scale automated production, but the produced graphene sheets suffer from structural and morphological defects that degrade considerably the mechanical and other physical properties of synthesized graphene. Recently, the use of liquid metal catalysts (LMCat) has been proposed as an alternative platform for facile and high‐quality synthesis of single‐crystal graphene. Herein, simultaneous Raman spectroscopy combined with mechanical testing is adopted confirming that the reinforcing efficiency of the LMCat graphene is greatly improved. In fact, the effective Young's modulus of LMCat graphene has been found ≈630 GPa, which is significantly higher than the graphene grown on solid Cu substrate due to differences in the morphology of Cu substrate. Overall, this work paves the way for the development of defect‐free graphene of quality comparable to exfoliated flakes, and this will have a major technological impact for many applications.

Active Sites and Their Individual Turnover Frequencies for Ethylene Hydrogenation on Reduced Graphene Aerogel.

Graphene aerogel (GA) was reduced at various temperatures to prepare a series of reduced graphene aerogels (rGAs) with different surface characteristics. Detailed characterization demonstrated that an increase in the thermal reduction temperature leads to an increase in surface area accompanied by an increase in surface density of defect sites formed by the removal of the oxygen-containing functional groups. rGA samples were then tested for ethylene hydrogenation under identical conditions. A comparison of catalytic performances of each catalyst demonstrated that the rGA sample prepared by reduction in Ar at 900 °C (rGA-900) provides the highest performance compared with others prepared at lower temperatures. Next, we analyzed the per-gram activity of each catalyst as a sum of individual contributions from different defect sites quantified by Raman spectroscopy and CHNS-O analysis to determine the individual turnover frequencies (TOFs) of each active site. This analysis identified polyene-like structures and interstitial defects associated with amorphous sp2 bonded carbon atoms as the dominant active sites responsible for hydrogenation. A comparison of their TOFs further indicated that the polyene-like structures provide approximately ten times higher TOF compared to those associated with the amorphous carbon defects. These results, identifying the dominant active centers and quantifying their corresponding TOFs, provide opportunities toward the rational design of GA-based carbocatalysts.

Carbon Nanotube – Synthesis, Purification and Biomedical Applications

Abstract: Carbon nanotubes (CNTs) are a relatively new class of technical materials with a variety of unique and beneficial features. CNT is a revolutionary carrier technology for both tiny and big medicinal compounds. These formulations can be surface engineered and functionalized with predefined functional groups to control their physical and biological characteristics. CNTs have proven potential for cancer therapy along with other target-oriented therapy due to their unique features, such as ease of cell viability, high drug stacking, thermal ablation, and exceptional intrinsic physical and chemical characteristics. Graphite with Sp2 bonded carbon atoms is used for the synthesis of CNT. CNTs are fabricated in a variety of ways, including arc discharge, laser ablation, chemical vapor deposition, flame synthesis, and silane solution. The present review summarises methods of preparation, types, and various applications of CNT.

Multilayer composite membranes composed of carbon molecular sieve membranes sandwiched between stacked zeolite nanosheets

This study proposes a novel method for fabricating composite membranes with a unique multilayer structure comprising Mobil-type five (MFI) zeolite nanosheets and carbon molecular sieve (CMS) membranes. The proposed fabrication method involves direct solution casting of a nanosheet/polymer composite onto porous alumina supports and subsequent carbonization, thereby eliminating the necessity for intermediate layers, typically required in most conventional supported CMS membranes. The fabricated membranes exhibit clear molecular sieving separation attributes, demonstrating the efficiency of the proposed method in preparing membranes without intermediate layers. Furthermore, the membranes exhibit an intriguing morphological configuration, wherein the CMS layers occupy the interstitial spaces between the stacked zeolite nanosheets. Therefore, compared with conventional CMS membranes without nanosheets, the fabricated CMS membrane with MFI nanosheets contain a significant proportion of sp2 bonded carbon atoms. The distinct physical and chemical structures of the composite membrane considerably improve its stability against structural densification associated with physical aging. A marginal H2 permeance reduction is observed for the 6 and 10 wt% loading samples of the composite membrane after aging for 100 d at 180 °C. Moreover, the H2/CO2 selectivity of the 6 wt% loading sample of the aged membrane increased from approximately 4 to 21, surpassing the upper bound of the corresponding gas pair. Thus, the proposed method can be used for fabricating molecular sieve membranes owing to its advantages such as ease of membrane preparation and gas-separation performance and structural stability enhancements of the fabricated membranes.

Tubular Diamond as an Efficient Electron Field Emitter

Herein, we present a straightforward and cost-effective procedure for producing conductive diamond tubes on the surface of porous carbon nanotube hollow fibers using successive 10-pulsed laser annealing shots and 6 h of hot filament chemical vapor deposition techniques. Room-temperature Raman and X-ray diffraction spectra reveal the signature T2g peaks near 1332.4 cm–1 and 111 planes of diamonds near 43.9°, respectively. A low turn-on field (ETO) ∼1.85 V/μm@1 μA/cm2 and a threshold field (ETH) ∼2.54 V/μm@10 μA/cm2 were observed for the tubular diamond structures. The field enhancement factor (β) was calculated at 3594 and highly stable field emission current stability was observed over a long period of 4 h. For the first time, a good insight into the field emission results of the diamond is established with the structural, electronic properties, and the work function (φ) ∼4.84 eV analysis conducted by the density functional theory simulation. Finite electronic states at the Fermi level are observed beyond a band gap, and it demonstrates the wide-band gap (4.4 eV) semiconducting nature of the diamond. The Bader charge analysis and maximum entropy method pattern revealed the negative electron affinity of the diamond, and it is responsible for the emission of electrons from the conduction band of the diamond. Besides, the accumulation of charge carriers, which contributes to the electric field emission, takes place due to the weak π bonds of carbon atoms. The low turn-on field, the high field enhancement factor, and the good field emission current stability of tubular diamond offer great prospects for future efficient and low-cost field emission devices.

Theoretical Investigation and Synthesis Strategy of ‘<i>hypervalent’</i> Carbon

<i>Hypervalent</i> compounds using main group elements are often used as reagents in the variety of interesting reactions in chemistry, such as in the total synthesis of some important natural products and/or drugs, as molecular switch, as oxidizing agents, in the synthesis of novel polymers, in rearrangement reactions, in oxidative cleavage reactions, in activation of small molecules (such as H₂, O₂, O₃, P₄…) etc. However, although <i>hypervalent</i> compounds of main group elements are well known, there are a few examples in the literature about DFT-calculation and synthesis strategy of <i>hypervalent</i> carbon compounds. Some scientists are still of the opinion that carbon atom does not have the ability to form hypervalent carbon bonds. Therefore, they argue that <i>multiple</i> bonded (more than 4 bond) carbon atoms should be termed "<i>hypercoordinated</i>". The fact is that both “<i>hypervalent</i>” carbon compounds and “<i>hypercoordinated</i>” carbon compounds existed. However, there are certain requirements for a <i>multiple</i> bonded carbon compound to be called "<i>hypervalent</i>". The most important requirements are the bond length, the existence of 3c–4e bonding mode and the bound ligand to carbon. This review discusses the conditions for the <i>hypevalence</i> and summarizes, analyzes the established synthesis strategy and some important DFT-calculation of <i>hypervalent</i> carbon compounds.

Characteristics of humic acids in sod-podzolic soil under long-term exposure to different fertilization systems

The elemental composition and structure of humic acids in the soddy-podzolic heavy loamy soil of the Cis-Urals were studied during long-term application of organic, mineral and organo-mineral fertilizers under conditions of a long-term stationary experiment. Mineral fertilizers contributed to the formation of humic acids with increased content of aliphatic components, the ratio H : C = 1.45 and a high degree of oxidation (ω = 0.41). The low content of nitrogen in humic acids (from 2.0 to 2.6 at.%), with various fertilizer systems, is primarily due to its low content in the plant biomass of crops cultivated in crop rotation.The organic fertilizer system resulted in the enrichment of the structural aggregates of humic acids with aromatic groups and nitrogen. The high intensity of absorption of the &gt;C=O group of carboxylic acids in the region of 1 717 cm-1 and double bonds of carbon atoms at 1 627 cm-1 confirms this position. Humic acids of the “manure 10 t/ha” and “manure 5 t/ha + equiv. NPK” have the largest number of carboxyl groups in their composition. The vibrations of the &gt;C=O group of carboxylic acids are most weakly expressed in soil humic acids with a mineral fertilizer system. Organo-mineral fertilizer system demonstrates intermediate results in terms of the content of the main constitutional elements in humic acids. Mineral fertilizers application reduces the amount and thermal stability of the structural components of humic acids, thereby contributing to the degradation of the most stable part of macromolecule, which can lead to the loss of potential soil fertility. Тhe use of mineral fertilizers on sod-podzolic heavy loamy soil led to the enrichment of humic acids with aliphatic fragments, and of organic ones – increased the content of stable components of aromatic nature, but lowered their thermal stability. According to thermographic analysis the ratio of weight loss in the low-temperature zone and the weight loss in the high-temperature zone (Z) during long-term use of mineral fertilizers is 0.9, i. e. the proportion of components of aliphatic nature in the structure of humic acids increases in comparison with unfertilized or manure fertilized soil.

A Study on Reduced Graphene Oxide in Large-area Transparent Heaters for Defrosting

Transparent heaters are promising devices because of their versatile applications in vehicles, smart windows, and sensors, etc. Indium tin oxide is widely used for transparent heater materials due to its high electronic conductivity and visible light transmittance. However, the cost of indium is too high, and its fabrication needs sophisticated processes, so that many studies have focused on alternative materials which are inexpensive and easy-to-synthesize. Graphene is a two-dimensional material in which carbon atoms bond to form a hexagonal structure, and it can be an alternative material due to its superior electronic/ thermal conductivity and cost-effectiveness. Here, we chemically treated graphite to synthesize large-sized graphene oxide (LGO), and coated it on a glass substrate, followed by reduction using hydrogen iodide for large-sized reduced graphene oxide (LrGO) on glass. From surface characterizations, we confirmed that the lateral size of the LGO was over 50 μm and the LGO sheets were uniformly coated on the glass, which minimized intersheet contact resistance. Structural characterizations demonstrated that the LGO sheets were reduced to LrGO and the LrGO sheets coated on the glass showed a transmittance of 76.2 % at 550 nm with a sheet resistance of 0.98 kΩ. Finally, the temperature of the substrate increased up to 30 oC when 30 V of voltage was applied for 5 min, and the frost on the glass surface vanished within 1 min.

Laser surface modification on rGO/ZnO composite materials for NO2 gas sensing

The nanosecond pulsed ultraviolet laser to modify the graphene composite materials (rGO/ZnO) and improve gas sensing response. The electrical resistance decreased from 2.72 × 103 to 1.13 × 103 Ω/square. The XPS results revealed that the ratio of oxygen to carbon atoms decreased from 33.73 to 12.59%. The bonding structure indicated that the ratio of sp2 bonds of carbon atoms increased and that the sp2 bonds replaced the original sp3 bonds, yielding a material structure that is similar to a complete graphene structure. In the NO2 gas sensing experiment, tests were performed with 5 ppm concentration of NO2 standard gas. Compared with the specimens with rGO sensing materials, those with rGO/ZnO sensing materials could detect gas before laser surface modification. In the 5 ppm NO2 gas concentration, the rGO/ZnO sensing material had 4.2% gas response; after laser surface modification, the gas response with increased to 6.2%. Testing results for gas response under various NO2 standard gas concentrations after laser surface modification revealed that the specimen had a gas response of 11.0%, 14.8%, and 23.7% at the NO2 standard gas concentrations of 10, 30, and 50 ppm, respectively.

Monoclinic mC28 carbon: A sp2-sp3 hybridized carbon allotrope with superhard and metallic properties

• A novel carbon structure with mixed sp 2 and sp 3 bonds (named as mC 28 carbon) was theoretically proposed. • The mC 28 carbon is dynamically stable and has a lower enthalpy than graphite under ~ 29 GPa, which implied it could be a metastable phase of carbon. • It is also calculated to be a metal combined with high hardness (the calculated Vickers hardness value reached 85 GPa ) New carbon allotropes with mixed sp , sp 2 and sp 3 bonds are now the focus of theoretical and experimental researches due to their abnormal properties. We here theoretically proposed a novel three-dimensional carbon structure with mixed sp 2 and sp 3 bonds (named as mC 28 carbon) via particle swarm optimization method. mC 28 carbon is built by the ‘diamond-like’ sp 3 networks connected by sp 2 bonded carbon atoms. It has a lower enthalpy than graphite after ∼29 GPa and is dynamically stable at zero pressure. More interesting, mC 28 carbon is metallic, which can be attributed to the connected sp 2 bonding carbon atoms. They provide a channel for their extra delocalized valence electron that siting at p z orbital. mC 28 carbon is also a superhard material with theoretical Vickers hardness of 85 GPa.

Carbon Nanostructures As Antibacterials and Active Food-Packaging Materials: A Review.

In this article, we discuss carbon nanoparticles for application as antibacterials and food-packaging materials. The use of petroleum-derived products, synthetic materials, ceramics, wax, etc. in the food-packaging industry emits polluted gas and wastewater, which leads to environmental pollution. To overcome the problems faced by the industry to preserve and package food, carbon nanomaterials may be good alternatives to enhance the shelf life of food without affecting the nutrients. Carbon atoms bond with each other in diverse ways to form many allotropes, resulting in a variety of carbon nanomaterials (CNMs). CNMs include zero-dimensional carbon dots, graphene quantum dots, 1-dimensional carbon nanotubes, 2-dimensional pristine graphene, graphene oxide, reduced graphene oxide, and other derivatives of graphene. Most of the carbon-based nanomaterials are synthesized through a green process that is widely used in the field of food science and technology, and they are used mostly as antibacterial agents and as a biofiller in the development of active food-packaging materials. Carbon nanomaterials (CNMs), viz., carbon dots, graphene, activated carbon-based nanocomposites, carbon nanotubes, etc., are found to be environmentally benign and better materials for food packaging. With antibacterial efficiency, they support food preservation and other applications as well. Thus, carbon nanostructures are found to be applicable as superior materials for food preservation and packaging in modern industry.

Divergent isoindolinone synthesis through palladium-catalyzed isocyanide bridging C–H activation

The formation of thermodynamically accessible metallacycle is crucial to achieve site-selective C–H bond activation. Here, we report an isocyanide-bridging C–H activation through the formation of a five-membered palladacycle. As such, a proximal C–H bond in aldehyde moiety is activated selectively. The subsequent palladium shift and intramolecular C=N bond insertion construct a valuable isoindolinone framework. Compared with conventional isocyanide-promoted C–H bond activation, both carbon and nitrogen atoms in isocyanide are engaged in new bond formations. Notably, three types of isoindolinones can be obtained selectively by variations of the reaction conditions. Mechanistic studies shed light on the reaction pathways. Moreover, the synthetic potential of current methodology is demonstrated by providing concise routes to key intermediates of indoprofen, indobufen, aristolactams, lennoxamine, and falipamil. • Isocyanide-bridging C–H activation • A new reaction mode for C–H bond functionalization • Divergent preparation of isoindolinone derivatives • Potential applications in bio-active molecule synthesis Metallocycles are commonly used to direct C–H bond activation. Here, Zhang et al. describe a palladium-catalyzed isocyanide-bridging C–H activation in which the isocyanide moiety not only acts as a bridging unit to facilitate a proximal C–H bond activation but also serves as a two-atom building block to construct the three different substituted isoindolinone derivatives.

A new insight into the push‐pull effect of substituents via the stilbene‐like model compounds

AbstractIn this paper, authors report on 1‐pyridyl‐2‐arylethenes, 1‐furyl‐2‐arylethylenes, 1,2‐diphenylpropylenes and substituted cinnamyl anilines as stilbene‐like model compounds to investigate the factors dominating the push‐pull effect of substituents via using the nuclear magnetic resonance chemical shift of bridging bond carbon atoms. It is demonstrated that the maximum push‐pull effect is not always between the strong electron‐donating D and strong electron‐accepting A groups in D‐π‐A compounds. The action mode of push‐pull effect of substituents in D‐π‐A compounds is dominated by their molecular parent structure. The contribution of field/inductive effect and conjugative effect of a group to the push‐pull effect is unequal. When the D‐π‐A parent molecule is in a plane, the influence of field/inductive effect of a group on the push‐pull effect is greater than or close to that of its conjugative effect does. Although the parent molecule is sterically twisted, the push‐pull effect is mainly dependent on the conjugative effect of a group. The results of this paper can provide us a new insight into the push‐pull effect of substituents.

Review on Graphene Nanoparticle Composites

In recent years, graphene has attracted atlcntion. Grapheneis a thick planar sheet of Sp2 bonded carbon atoms. Its lattice is honey comb structure. Graphene is one of the most rising material due to its various fascinatingl properties. From recent study it is proved that graphene based composites with different nanoparticle show extensive applielltion. In this review we focus on recent developement in the synthetic approach, properties and the facilities of use of graph nanoparticle comosites. The advantages of graphene-nanupartide composites are specifically observed in catalytic reactions, electrochemical sensing, detection by surface enhanced Raman spectroscopy, purification of waterusing adsurbent and other applications are discussed here.

First-Principles Research of Interaction between 3d-Transition Metal Ions and a Graphene Divacancy on the Supercomputer Base

Density functional theory method was used to study the interaction of 3d-transition metal ions with divacancy in graphene. Calculations demonstrate that in all cases, except for that of the structure with the Sc ion, the metal is located in the divacancy center, compensating for the four dangling chemical bonds of carbon atoms. Interaction energies are close to 1000 kJ/mol. The strongest interaction was found for the Ni ion. Analysis of the local density of states of nanoparticles shows that additional energy levels appear in the energy gap between the highest occupied and lowest unoccupied levels of the graphene cluster due to the presence of a transition metal ion. In the case of clusters with Co, Ti, and V ions, the highest occupied level of the cluster lies in the region of electronic states with non-zero local density on the ion.

The Influence of Starch-Based Carbon Aerogels Modifications on Their Irreversible Capacity during Initial Cycles in Li-Ion Cells

Carbon aerogels derived from starch (CAGs) are the new class of anode materials for Li-ion battery developed in our group [1-4]. They possess well-defined continuous structure of covalently bonded carbon atoms and exhibit special properties such as: large surface area, chemical and thermal stability, determined porosity, high electrical conductivity and high capacitance. These materials based on rice (RS), maize (MS) and potato (PS) starch represent better electrochemical parameters than graphite- higher specific capacity and the possibility of working properly under high current loads. All these features make them competitive not only in terms of the ecology and economy but also in terms of their behavior in Li-ion cell [1-4].Although the amorphous carbons derived from biomass are one of the promising candidates among widely studied anode materials, they also have disadvantages. The main issue preventing their commercialization is their huge irreversible capacity, that results from the active lithium losses, during the first cycles of working in Li-ion battery. This low initial coulombic efficiency is caused by the lithium consuming parasitic reactions. One of them can be ascribed to the solid electrolyte interphase (SEI) formation that is created by the reductive decomposition of the electrolyte solvents and the irreversible reaction of Li+ with functional groups (such as carboxyl, hydroxyl etc.) on the carbon surface. The other is connected with the irreversible insertion of lithium ions, that can be trapped into closed micropores in the carbon matrix [5-7].The main goal of this project is to determine the effect of carbon aerogels surface modification on their irreversible capacity during the initial cycling. The surface modification of bio-derived aerogels is performed by using different pyrolysis conditions (temperature, gas medium) as well as by chemical treatment. This process is needed for changing the morphology of studied materials (improve the porosity with maintain the proper surface development) in order to reduce the effect of trapping lithium ions and remove the easily reducible surface groups. The key parameter is to find the optimum between surface development, porosity and electrochemical behavior of the carbon materials. All these actions aimed to ameliorate the reversibility during first cycle of operation in Li-ion battery. Following experimental methods are used in characterization of the modified materials and evaluation of the applied methods: powder X-ray powder diffraction (XRD), elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), low temperature nitrogen adsorption/desorption method (N2-BET), galvanostatic charge-discharge tests (GCDT), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). ACKNOWLEDGMENT This work is supported by the National Science Centre – Poland, under grants no. 2019/33/N/ST8/01687.[1] M. Bakierska, M. Molenda, A. Chojnacka, M. Świętosławski, PCT/IB2017/050591 (3.02.2017)[2] M. Bakierska, M. Lis, J. Pacek, M. Świętosławski, M. Gajewska, A. Tąta, E. Proniewicz, M. Molenda, Carbon 145 (2019) 426[3] M. Lis, K. Chudzik, M. Bakierska, M. Świętosławski, M. Gajewska, M. Rutkowska, M. Molenda, J. Electrochem. Soc. 166/3 (2019) A5354[4] M. Kubicka, M. Bakierska, K. Chudzik, M. Rutkowska, J. Pacek, M. Molenda, Polymers 11(9) (2019) 1527[5] N.A. Kaskheidikar, J. Maier, Adv. Mater. 21 (2009) 2664[6] X. Zhang, C. Fan, S. Han, J. Mater. Sci. 52 (2017) 10418[7] R. Fong, U.V. Sacken, J.R. Dahn, J. Electrochem. Soc. 137 (1990) 2009

Effect of electron-phonon interaction and valence band edge shift for carrier-type reversal in layered ZnS/rGO nanocomposites

The artificial stacking of nanohybrid films helps to enhance their properties and thus intrigues researchers to explore this possibility in emerging technologies. The layer-by-layer approach was used to fabricate samples of zinc sulfide/reduced graphene oxide (ZnS/rGO) by using spin coating technique. The structure and optoelectronic properties has been extensively studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV–VIS-NIR spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Hall measurements. Raman spectrum elucidates the phonon contribution of ZnS and breathing mode of κ-point phonons and sp2 bonds of carbon atoms of rGO. The electron-phonon interactions reveal reduction in electron mobility and enhancement in holes contribution with rGO content leading to surface charge transfer doping (SCTD). XPS results explain the valence band edge and conduction band edge to form type-I band alignment to reconfirm carrier-type reversal. A change in the dispersion of refractive indices along with a small rise in the value of absorption coefficient in terahertz (THz) region for ZnS/rGO nanocomposite films has been observed. These results will open up new opportunities to furthering the science of this technologically important class of materials for future electronics.

Edge-Plane Exposed N-Doped Carbon Nanofibers Toward Fast K-Ion Adsorption/Diffusion Kinetics for K-Ion Capacitors

Sluggish kinetics severely limit the development of potassium-ion hybrid capacitors (PIHCs). Exposing active sites is recognized as an ideal strategy to resolve this issue, but the corresponding ma...

FEATURES OF ULTRASONIC SPLITTING OF THERMALLY EXPANDED GRAPHITE

Thermally expanded graphite is obtained from crucible graphite by treatment with oleum in the presence of an oxidizing agent. The obtained samples of thermally expanded graphite were subjected to ultrasonic dispersion (splitting up) in four liquid media (water, toluene, benzene, acetone). It was shown that in the process of ultrasonic dispersion (splitting), the initial thermally expanded graphite is split into plates with a thickness of several tens to hundreds of nanometers. However, the plates are not single, but are in chaotic clusters with each other. The free bonds of carbon atoms, which are located at the edges of the plates, can play an important role in chemical processes and in the adsorption of substances on the surface of particles of split graphite. It was found that a high degree of perfection of the crystal structure, which is typical of the original graphite, is retained during ultrasonic treatment as compared with mechanical splitting. The change in the specific surface of graphite samples is presented. The main increase in the specific surface of the particles during ultrasonic splitting is created by increasing the area of the surfaces formed during interplanar splitting of graphite plates. Based on the comparison of this parameter, the effect of the used liquids on the splitting process is considered. The high values of the specific surface of the samples split in benzene and toluene are explained by the low values of the surface tension. The good wettability of the graphite surface with benzene, toluene and acetone compared with water allows these liquids to penetrate deep into the pores of graphite. Due to this, maximum splitting is achieved with ultrasonic processing of the mixture. Conclusions on the choice of the optimal liquid medium for dispersing graphite are made.

Effect of He ion irradiation on microstructure and electrical properties of graphene

Graphene is a planar two-dimensional material composed of sp&lt;sup&gt;2&lt;/sup&gt;-bonded carbon atoms with extraordinary electrical, optical and mechanical properties, and considered as one of the revolutionary electronic component materials in the future. Some studies have shown that the inert gas ion irradiation as a defect introducing technique can change the structure and properties of graphene without introducing additional effects. In this paper, the 5.4 keV He ion irradiation at the dose ranging from 0.7 × 10&lt;sup&gt;13&lt;/sup&gt; cm&lt;sup&gt;–2&lt;/sup&gt; to 2.5 × 10&lt;sup&gt;13&lt;/sup&gt; cm&lt;sup&gt;–2&lt;/sup&gt; has a strong effect on graphene deposited by CVD technology. The X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (Raman) and semi-conductor parameter analysis instrument are used to study the changes in the microstructure and electrical properties of graphene before and after irradiation. Detailed analysis shows that the defect density increases gradually with the irradiation dose increasing. Raman spectrum shows that when the irradiation dose increases to 1.6 × 10&lt;sup&gt;13&lt;/sup&gt; cm&lt;sup&gt;–2&lt;/sup&gt;, the value of &lt;i&gt;I&lt;/i&gt;&lt;sub&gt;D&lt;/sub&gt;/&lt;i&gt;I&lt;/i&gt;&lt;sub&gt;G&lt;/sub&gt; begins to decrease, and XPS shows that the irradiation changes the structure of C chemical bond in graphene which causes the bonding state of C—C sp&lt;sup&gt;2&lt;/sup&gt; to be destroyed and partly converted into the C—C sp&lt;sup&gt;3&lt;/sup&gt; bonding state. Therefore, the structure of graphene begins to transform from nano-crystalline structure into sp&lt;sup&gt;3&lt;/sup&gt; amorphous structure. Simultaneously, increasing defects causes the graphene conductivity to continuously decrease, and also gives rise to the electrical transition from defect scattering mechanism based on Boltzmann transport to the hopping transport. The positive voltage direction offset of &lt;i&gt;V&lt;/i&gt;&lt;sub&gt;dirac&lt;/sub&gt; increases nearly in direct proportion, which is due to the enhancement of graphene’s p-type doping effect caused by defects and adsorbed impurities. This work conduces to the understanding the mechanism of He ion interaction with graphene, and also provides an effective way of controlling the electronic properties.