Graphite Substrate Research Articles

Anodized graphite as an advanced substrate for electrodeposition of PbO2

Graphite plate has been employed as a crucial substrate for electrodeposition of PbO2 to increase charge transfer and electronic conductivity. This work is evaluated the effect of electrochemical pretreatment (anodization in alkaline, acidic, and buffer solution) on graphite substrate to be reported as an advanced substrate for PbO2 electrodeposition. The morphological features and electrochemical performance are analyzed by using field emission scanning electron microscopy (FESEM), Atomic Force Microscopy (AFM), X-Ray diffraction (XRD), chronopotentiometry, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Linear sweep voltammetry (LSV) and Tafel plot. The results are indicated that the roughness, porosity, and capacitance are increased after the anodization. Also, the charge transfer resistance is decreased for oxygen evolution reactions on the graphite surface. Although alkaline anodization is provided the lowest electrical capacitance, it is created the highest charge transfer resistance in comparison to acidic and buffer anodization. The deposition of PbO2 on the alkaline anodized graphite substrate is formed the porous PbO2 architecture with small particle sizes and the highest current efficiency. It also is shown the lowest ohmic resistance (0.48 ohm) and charge transfer resistance (2.44 ohm). Therefore, the result can be drawn that the electrochemical activity of PbO2 coated on BG could be enhanced by the alkaline anodization of graphite substrate.

Facile Edge Functionalization of Graphene Layers with a Biosourced 2-Pyrone

Edge functionalization of graphene layers is of great interest in the field of materials chemistry: the properties of graphene are substantially unaltered and its compatibility and chemical reactivity with various environments can be tuned. In this work, edge functionalization of graphene layers was performed with a 2-pyrone, ethyl 3-hydroxy-2-oxo-2H-pyran-6-carboxylate (Pyr-COOEt). 2-Pyrones are C-6 unsaturated heterocyclic sugar derivatives and are intriguing building blocks for the preparation of innovative chemical structures. Sodium 3-acetoxy-2-oxo-2H-pyran-6-carboxylate was prepared starting from mucic acid, in a one-pot synthesis with a yield of about 74%, and was then transformed into the acid and then into ethyl ester derivatives. The adduct of Pyr-COOEt with a high surface area graphite (HSAG) was obtained by simply mixing and donating energy, either thermal or mechanical. The functionalization yield was estimated from thermogravimetric analysis (TGA) data and was found to be up to 91%. The adducts were characterized by Fourier transform infrared and Raman spectroscopies and wide-angle X-ray diffraction. The presence of pyrone in the adduct was clearly detected in the IR spectra, and the bulk structure of the graphitic substrate was found to be substantially unaltered by the functionalization reaction. The experimental findings suggest that the edge functionalization of the graphene layers occurred. Stable water dispersions of HSAG/Pyr adducts were prepared and studied through ultraviolet–visible analysis. Aggregates of few-layer graphene were obtained by mild sonication and centrifugation, as revealed by high-resolution transmission electron microscopy. This paper shows that a biobased molecule can be used for selectively decorating the edges of graphene layers, with oxygenated functional groups having a defined chemical structure and avoiding the use of oil-based, dangerous, and even noxious ingredients. The most plausible interpretation for the formation of the HSAG adduct with 2-pyrone seems to be the cycloaddition reaction between the edges of the graphitic substrate and the unsaturated biomolecule. Such a functionalization appears to be suitable for a scale up and paves the way for the preparation of a variety of derivatives.

Catalytic Properties of Free-Base Porphyrin Modified Graphite Electrodes for Electrochemical Water Splitting in Alkaline Medium

Hydrogen generation via electrochemical water splitting is considered an eco-friendly pathway for obtaining this desired alternative energy source, and it has triggered an intensive search for low cost and efficient catalysts. Within this context, four free-base porphyrins were studied as heterogeneous catalysts for the oxygen and hydrogen evolution reactions (OER and HER) in alkaline aqueous solutions. TEM and STEM analyses of samples obtained by drop-casting the porphyrins from different organic solvents on TEM grids revealed a rich variety of aggregates due to the self-assembling property of the porphyrin molecules. Modified electrodes were manufactured by applying the four tetrapyrrolic macrocycles from various solvents on the surface of graphite supports, in one or more layers. Experiments performed in 0.1 M and 1 M KOH electrolyte solutions allowed the identification of the most electrocatalytically active electrodes for the OER and HER, respectively. In the first case, the electrode was manufactured by applying three layers of 5-(4-pyridyl)-10,15,20-tris(4-phenoxyphenyl)porphyrin on the graphite substrate from N,N-dimethylformamide solution was identified as overall catalytically superior. In the second case, the electrode obtained by applying one layer of 5,10,15,20-tetrakis(4-allyloxyphenyl)-porphyrin from benzonitrile solution displayed an HER overpotential value of 500 mV at i = −10 mA/cm2 and a Tafel slope of 190 mV/dec.

Analysis of Metal Elements Contained in Graphite Target Coated With Chinese Medicinal Material Nanoparticles Using LIBS

A nanoparticle-coated graphite target (NCGT) is presented to improve the analysis accuracy and stability of laser-induced breakdown spectroscopy (LIBS). A stable, relatively homogeneous, and close to optically thin laser-induced breakdown plasma was obtained by dispersing sample nanoparticles on a high-purity graphite substrate. Spectral structures dominated by the characteristic lines of carbon and the samples can greatly simplify spectral identification and avoid line interference. To maximize the analysis accuracy and stability, a series of experimental conditions were optimized step by step according to the spectral intensity and signal-to-noise ratio of the lines. Based on the final optimized conditions, the relative standard deviation values of Mg, Fe, and Sr elemental content in Chinese medicinal material (CMM) samples were reduced from 17.7, 16.6, 12.1% of the pressed target to 4.8, 9.5, and 4.5% of the NCGT, respectively. Comparisons with the inductively coupled plasma mass spectrometry (ICP-MS) results demonstrated that the present method has great potential for detection of LIBS.

Morphological study of isotactic polypropylene thin films on different substrates using grazing incidence wide-angle X-ray diffraction

Isotactic polypropylene (iPP) is one of the most commonly used polymers owing to its excellent mechanical properties and well-balanced physical properties. These properties can be achieved and controlled through a better understanding of its hierarchical structures. The crystal structures of iPP thin films of ∼120 nm thickness formed on graphite and silicon substrates were investigated via grazing incidence wide-angle X-ray diffraction (GIWAXD) with hard and tender X-rays along with grazing incidence small-angle X-ray scattering, atomic force microscopy, and transmission electron microscopy. The lamellae were found to be edge-on-oriented on the graphite substrate due to epitaxial iPP crystal growth and flat-on-oriented on the silicon substrate due to iPP crystal growth along the thermodynamically dominant orientation. GIWAXD results obtained with tender X-rays revealed that the orientation of the crystal lamellae did not change along the thickness direction and that the degree of crystallinity at the surface was lower than that in the interior of the iPP thin films for each substrate. These results indicate that crystallization at the substrate-film interface played a significant role in the formation of the crystal structure of the iPP thin film, that is, the crystals grew throughout the thin films along the substrate-induced orientation even in the case of edge-on orientation, where the growth axes of the crosshatched lamellae were not parallel to the thickness direction. The relationship between the growth axes of lamella and the growth of surface-induced orientation along the normal direction of the substrates was successfully clarified for the first time using the thin film systems. The obtained results can be extended to interface-induced crystallization inside bulk composite materials.

Intensified ceria recovery from graphite substrate and cleanup of leachant using sonication

There is a huge environmental concern for disposal of nuclear graphite. The current work demonstrates sonochemical decontamination of graphite using ceria coating as the simulated contamination. The ceria recovery in the leachant solution, demonstrated to drastically reduce by almost 50% beyond 30 min sonication, was attributed to the adsorption of cerium ions by the generated carbon residue due to exfoliation of graphite. The study of the carbon residue enabled to understand the anomaly in the observed kinetics and the role of the carbon residue in the removal of Ce3+ from the leach liquor. The recyclability of the graphite substrate has been studied by measuring its compressive strength and electrical conductivity before and after 7 h of sonication in nitric acid. The decontamination kinetics of graphite was found to follow the surface reaction controlled mechanism and cavitation was found to lower the activation energy from 102 to 80 kJ/mol. Overall, ultrasound was found to bring about a threefold increase in the ceria recovery over a silent process (in the absence of ultrasound). The decontamination and the recyclability of graphite demonstrated here will facilitate circular economy and serve as an important remediation technique.

Nanoscale Topographical Effects on the Adsorption Behavior of Bone Morphogenetic Protein-2 on Graphite.

The interaction between bone morphogenetic protein-2 (BMP-2) and the surface of biomaterials is essential for the restoration of bone and cartilage tissue, inducing cellular differentiation and proliferation. The properties of the surface, including topology features, regulate the conformation and bioactivity of the protein. In this research, we investigated the influence of nanopatterned surfaces on the interaction of a homodimer BMP-2 with graphite material by combining molecular dynamics (MD) and steered molecular dynamics (SMD) simulations. The graphite substrates were patterned as flat, linear grating, square, and circular profiles in combination with BMP-2 conformation in the side-on configuration. Ramachandran plots for the wrist and knuckle epitopes indicated no steric hindrances and provided binding sites to type I and type II receptors. Results showed two optimal patterns that increased protein adsorption of the lower monomer while preserving the secondary structure and leaving the upper monomer free to interact with the cells. Charged residues arginine and lysine and polar residues histidine and tyrosine were the main residues responsible for the strong interaction with the graphite surface. This research provides new molecular-level insights to further understand the mechanisms underlying protein adsorption on nanoscale patterned substrates.

From 2D to 3D: Bridging Self-Assembled Monolayers to a Substrate-Induced Polymorph in a Molecular Semiconductor

In this study, a new bottom-up approach is proposed to predict the crystal structure of the substrate-induced polymorph (SIP) of an archetypal molecular semiconductor. In spite of intense efforts, the formation mechanism of SIPs is still not fully understood, and predicting their crystal structure is a very delicate task. Here, we selected lead phthalocyanine (PbPc) as a prototypical molecular material because it is a highly symmetrical yet nonplanar molecule and we demonstrate that the growth and crystal structure of the PbPc SIPs can be templated by the corresponding physisorbed self-assembled molecular networks (SAMNs). Starting from SAMNs of PbPc formed at the solution/graphite interface, the structural and energetic aspects of the assembly were studied by a combination of in situ scanning tunneling microscopy and multiscale computational chemistry approach. Then, the growth of a PbPc SIP on top of the physisorbed monolayer was modeled without prior experimental knowledge, from which the crystal structure of the SIP was predicted. The theoretical prediction of the SIP was verified by determining the crystal structure of PbPc thin films using X-ray diffraction techniques, revealing the formation of a new polymorph of PbPc on the graphite substrate. This study clearly illustrates the correlation between the SAMNs and SIPs, which are traditionally considered as two separate but conceptually connected research areas. This approach is applicable to molecular materials in general to predict the crystal structure of their SIPs.

Electrodeposition of nanoporous nickel selenide on graphite rod as a bifunctional electrocatalyst for hydrogen and oxygen evolution reactions

• A novel NiSe nanoelectrocatalyst was synthesized. • This nanostructure was obtained by controlling the electrodeposition conditions. • The synergistic effect and high surface area were the main affecting factors. • Comparing to Pt catalyst, the optimized electrode has an excellent HER performance. The purpose of this paper is to synthesize the nanoporous structure of nickel selenide by cyclic voltammetry technique on a graphite rod substrate that is active for water splitting. This is the first report of the manufacture of this morphology as impressive water splitting electrocatalyst on a graphite rod substrate using a rapid, one-step, and cost-effective electrodeposition technique. Herein, first, a graphite rod was modified with nickel selenide nanoporous by controlling the electrodeposition condition. The main outcomes reveal that the optimized Ni-Se coverage on graphite rod substrate illustrates hopeful HER acting with fewer overpotentials of −100.7, −281.3, and −552.9 mV at the current densities of −10, −100, and −400 mA. cm −2 , in order. Besides, the manufactured Ni-Se nanoporous catalyst is extremely energetic into OER, needing just 268 mV overpotentials for 10 mA. cm −2 current density. This research proposes a cost-effective and fast manner for manufacturing a novel nanoporous electrocatalyst that is a very active electrocatalyst for H 2 and O 2 improvement reactions. These outcomes propose that electrocatalyst is capable to be used for creating renewable-resource energy in industrial usage.

Corrosion of SiC-coated graphite susceptor by NH3 and Cl2

This study aims to investigate the corrosion of a SiC-coated graphite susceptor using NH3 and Cl2 in an epitaxial growth environment. The corrosion performance of NH3 with graphite and SiC-coated graphite was investigated through microstructure characterization and mass loss rate changes in detail. Gaseous NH3 had a high corrosion rate on the graphite substrate, but hardly reacted with the SiC coating. Additionally, analyses of the tested samples revealed that Cl2 gas corroded the SiC coating at high temperatures and formed many corrosion holes and residual free carbon on the surface. As the Cl2 concentration increased, the corrosion depth gradually increased. Further experiments on commercial SiC-coated graphite susceptors showed that Cl2 preferentially corroded the grain boundaries of the SiC coating, and then the grains were corroded, resulting in a decrease in the coating strength until cracking and failure.

Impact of Deposition Condition on the Morphology and Electrochemical Performance of Deposited F-Doped PbO2 on Graphite Substrate in Primary PbO2-Zn Battery

The impact of deposition process parameters (temperature, current density, Pb2+ concentration, and time of deposition) on morphology, electrical resistance, and discharge performance of a graphite/PbO2 cathode in a PbO2/zinc primary battery was investigated. The morphology, architecture, and phase composition of the PbO2 deposits were studied by FESEM, EDX, and XRD. The AC impedance and discharge tests were utilized for the exploration of the interfacial process and discharge performance of PbO2 deposits. The results indicate that the increment in temperature and decrease in current density leads to increased growth of PbO2 deposits with mainly β phase, formation of porous architecture, and a decrease in the charge transfer resistance (Rct). Also, with an increase in the deposition time to 30 min the Rct is increased due to the formation of PbO2 deposit with more uniform and compact structure. The deposition from 0.1 mol l‒1 Pb2+ solutions results in the formation of flower-like grains, a more porous surface, and lower Rct. However, because of concentration polarization, the PbO2 deposit prepared from 0.5 mol l‒1 of Pb2+ solutions, 55 °C temperature, 40 mA cm‒2 current density, and 15 min deposition time shows the best discharge performance.

Study of Structural and Optical Properties of Electrodeposited Silicon Films on Graphite Substrates.

Silicon (Si) films were deposited on low-cost graphite substrates by the electrochemical reduction of silicon dioxide nanoparticles (nano-SiO2) in calcium chloride (CaCl2), melted at 855 °C. Cyclic voltammetry (CV) was used to analyze the electrochemical reduction mechanism of SiO2 to form Si deposits on the graphite substrate. X-ray diffraction (XRD) along with Raman and photoluminescence (PL) results show that the crystallinity of the electrodeposited Si-films was improved with an increase of the applied reduction potential during the electrochemical process. Scanning electron microscopy (SEM) reveals that the size, shape, and morphology of the Si-layers can be controlled from Si nanowires to the microcrystalline Si particles by controlling the reduction potentials. In addition, the morphology of the obtained Si-layers seems to be correlated with both the substrate materials and particle size of the feed materials. Thus, the difference in the electron transfer rate at substrate/nano-SiO2 interface due to different applied reduction potentials along with the dissolution rate of SiO2 particles during the electrochemical reduction process were found to be crucial in determining the microstructural properties of the Si-films.

Mechanism of Silver Nanoparticles Deposition by Electrolysis and Electroless Methods on a Graphite Substrate

This study shows a silver electrodeposition model (EDM) on a graphite ‎substrate. The electrolyte was a 0.01 M solution of pure silver and chromium nitrate using an ‎electrolyzing cell. EDC with current density up to 20 mA/cm2 and 15 mV and pulse current were studied. Results revealed that silver deposited at a ‎rate of 0.515 mg/cm2/min with 12 mA /cm2 that decreases to 0.21 and 0.16 mg/cm2.min ‎with the decrease of current density to 6 and 5 mA/cm2 respectively. The model postulates that ‎silver ions (a) were first hydrated before diffusing (b) from the solution bulk to ‎the cathode vicinity, the next step (c) involved the chemical adsorption of these ions on certain ‎accessible sites of the graphite substrate (anode), the discharged entities (d) adhere to the graphite ‎surface by Van der Vales force. Silver ions are deposited because the ‎discharge potential of silver is low (0.38 mV) as compared to other metal ions like chromium (0.82 mV). Pulse ‎current controls silver deposition due to flexibility in controlling steps (a) - (c) of the ‎deposition mechanisms.

Si diffusion induced adhesion and corrosion resistance in annealed RF sputtered SiC films on graphite substrate

Silicon carbide (SiC) is one of the promising candidates for graphite protection in different applications involving high temperatures and a highly corrosive environment. An ideal Silicon carbide coating should withstand a corrosive environment without compromising its adhesion. Herein, RF magnetron sputtered silicon-rich SiC thin films were deposited on a graphite substrate followed by annealing at 1000 °C, 1200 °C, and 1400 °C in an inert atmosphere. The impact of annealing temperature on microstructure, adhesion and chemical stability of SiC thin films was demonstrated. Different analytical techniques like Scanning electron microscopy (SEM), X-Ray Diffraction (XRD), Fourier's Transform Infrared (FTIR) spectroscopy and nano-indentation were used to study microstructural evaluation and mechanical characteristics. Moreover, the electrochemical analysis (Tafel and Electrochemical impedance spectroscopy) was performed in 3.5% NaCl solution. The microstructural analysis revealed that the amorphous SiC thin film turned into a crystalline and dense film upon annealing. Scanning electron micrographs showed that silicon-rich regions at SiC film surface started to disappear as Si diffuses into graphite matrix at elevated temperatures. Both these factors contributed to improvement in the adhesion of SiC coating with graphite substrate as annealing temperature increased. In addition, the nano-indentation hardness of 5.2 GPa was obtained for as grown sample, which decreased at 1000 °C, and then increased at 1200 °C and 1400 °C. Furthermore, the electrochemical analysis confirmed the enhancement in corrosion resistance upon annealing at a temperature of 1200 °C and 1400 °C due to Si diffusion and film compactness in these samples.

Mechanism of Silver Nanoparticles Deposition by Electrolysis and Electroless Methods on a Graphite Substrate

This study shows a silver electrodeposition model (EDM) on a graphite substrate. The electrolyte was a 0.01 M solution of pure silver and chromium nitrate using an electrolyzing cell. EDC with current density up to 20 mA/cm2 and 15 mV and pulse current were studied. Results revealed that silver deposited at a rate of 0.515 mg/cm2/min with 12 mA/cm2 that decreases to 0.21 and 0.16 mg/cm2·min with the decrease of current density to 6 and 5 mA/cm2 respectively. The model postulates that silver ions (a) were first hydrated before diffusing (b) from the solution bulk to the cathode vicinity, The next step (c) involved the chemical adsorption of these ions on certain accessible sites of the graphite substrate (anode), The discharged entities (d) adhere to the graphite surface by Van der Vales force. Silver ions are deposited because the discharge potential of silver is low (0.38 mV) as compared to other metal ions like chromium (0.82 mV). Pulse current controls silver deposition due to flexibility in controlling steps (a)-(c) of the deposition mechanisms. Parameters like current density, current on-time, current-off time, duty cycle (ratio of current on time and total pulse time) and pulse frequency influenced the shape and size of the deposits. Step (b) suggested that silver particles were deposited in a monolayer thickness. The silver layer turned multiple after fully satisfying the accessible sites with the monolayer. The activation energy ΔE value amounts to 86.32 kJ/mol/K. At high temperature and current density, homogeneous diffusion occurs.

Direct observation of the Mottness and p-d orbital hybridization in the epitaxial monolayer α-RuCl3.

α-RuCl3, a promising material to accomplish the Kitaev honeycomb model, has attracted enormous interest recently. Mottness and p-d bonds play vital roles in generating Kitaev interactions and underpinning the potential exotic states of quantum magnets, and the van der Waals monolayer is considered to be a better platform to approach a two-dimensional Kitaev model than the bulk. Here, we worked out the growth art of an α-RuCl3 monolayer on a graphite substrate and studied its electronic structure, particularly the delicate orbital occupations, through scanning tunneling microscopy and spectroscopy. An in-plane lattice expansion of 2.67 ± 0.83% is observed and the pronounced t2g-pπ and eg-pσ hybridization are visualized. The Mott nature is unveiled by an ∼0.6 eV full gap at the Fermi level located inside the t2g-pπ manifold which is further verified by the density functional theory calculations. The monolayer phase of α-RuCl3 fulfills the a priori criteria of recent theoretical predictions of tuning the relevant properties in this material and provides a novel platform to explore the Kitaev physics.

Noncovalent wedging effect catalyzed the cis to syn transformation of a surface-adsorbed polymer backbone toward an unusual thermodynamically stable supramolecular product.

The significant influence of noncovalent interactions on catalytic processes has been recently appreciated but is still in its infancy. In this report, it is found that wedging Me-PTCDI (small-molecule) between the alkyl chains of PffBT4T-2OD (polymer) and a graphite substrate can reduce the energy barrier of flipping over the surface-adsorbed alkylthiophene group from the cis to syn conformation, revealing the catalytic role of Me-PTCDI via a noncovalent wedging effect. The wedging of Me-PTCDI brings the interactions between the alkyl chains and substrate to a very weak level by lifting up the alkyl chains, which eliminates the major hindrance of the flipping process to one main factor: the torsion of the dihedral angles of the thiophene group. The Me-PTCDI/syn PffBT4T-2OD arrangement shows unusual stability compared to the cis one because the syn conformation allows the alkyl chains to construct dense lamella and facilitates interactions between Me-PTCDI and the syn PffBT4T-2OD backbones. The results are helpful for boosting the development of noncovalent catalysis and bottom-up fabrications toward devices functionalized at a molecular level.

Novel coatings for graphite materials in PV silicon applications: A study of the surface wettability and interface interactions

Coatings are one of the promising techniques that can be applied to modify the surface properties and tailor the surface interactions with the surrounding. The development of conformable coatings for graphite materials can expand their use in silicon PV applications with no compromise on the silicon quality. However, no studies are focused on the coatings for graphite materials in silicon crystallization applications. Here we introduce different coating techniques that promise minimal interactions with the graphite and suppress the liquid silicon penetration. Five coating methods were proposed in this study: (i) one-layer coating: a mixture of silicon nitride and colloidal silica was directly coated on graphite substrates, (ii-iv) two-layer coating: a porous coating layer of silicon nitride, silicon carbide, or a combination of both materials was deposited as a protective layer below the top layer of Si3N4 and colloidal silica, and (v) a dense SiC layer was deposited on the graphite by silicon infiltration method below the top layer. The coatings’ wettability and interactions with graphite were investigated via in-situ melting experiments. The two-layer coating approach revealed a considerable improvement in the non-wetting behavior, a decrease in the coating degradation rate, and a decrease in CO evolution during the isothermal holding. The best non-wetting conditions with minimal detrimental interaction between graphite and silicon oxides were achieved by applying a two-layer coating with a thickness of 400 ± 50 μm and an initial oxygen concentration of 8 wt.% in the top layer. These findings can be utilized for the application of reusable graphite crucibles in silicon crystallization processes.

High electrochemical performance of ink solution based on manganese cobalt sulfide/reduced graphene oxide nano-composites for supercapacitor electrode materials.

Large scale supercapacitor electrodes were prepared by 3D-printing directly on a graphite paper substrate from ink solution containing manganese cobalt sulfide/reduced graphene oxide (MCS/rGO) nanocomposites. The MCS/rGO composite solution was synthesized through the dispersion of MCS NPs and rGO in dimethylformamide (DMF) solvent at room temperature. Their morphology and composition were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray diffraction (EDS). The role of rGO on decreasing charge transfer resistance and enhancing ion exchange was discussed. The MCS/rGO electrode exhibits an excellent specific capacitance of 3812.5 F g−1 at 2 A g−1 and it maintains 1780.8 F g−1 at a high current density of 50 A g−1. The cycling stability of the electrodes reveals capacitance retention of over 92% after 22 000 cycles at 50 A g−1.

Effect of gas atmospheres on the interactions between liquid silicon and coated graphite substrates

Interactions between the gas atmosphere, liquid silicon, Si 3 N 4 coating, and graphite are of great interest for photovoltaic silicon applications. However, previous studies focus more on the wetting of silicon on coated substrates rather than the coating stability and interaction with furnace atmosphere. Here we report on the coating deoxidation and the liquid silicon behavior at different compositions of nitrogen, carbon monoxide, and argon. In-situ melting experiments were performed with solar grade silicon samples in various gas compositions. The results showed a rapid reaction between molten silicon and carbon monoxide that led to the formation of a silicon carbide layer at the liquid free surface. This layer retains the silicon droplet at the early stage of wetting and prevents silicon infiltration and spreading. Furthermore, CO gas prohibits the self-reduction of SiO 2 in the coating and the reduction by graphite. On the other hand, nitrogen accelerates the wetting of silicon as it favors the formation of highly wetted silicon nitride compound at the triple line of the droplet. A slight increase in the decomposition rate of silica content in the coating was observed with the introduction of nitrogen to the furnace. The influence of the morphology and the growth of nitride and carbide layers on the wettability was elucidated in detail. The results were supported by Raman spectroscopy and thermodynamic calculations. • Effect of gas atmosphere on the wetting behavior. • Interactions at the liquid-coating interface and the coating-substrate interface. • Effect of gas atmosphere on the coating stability. • Kinetics and mechanism of the reactions between liquid silicon and gas phase.