X-ray Photoelectron Spectroscopy Survey Research Articles

Controlled Synthesis of Porous Carbon Nanostructures with Tunable Closed Mesopores via a Silica-Assisted Coassembly Strategy

Controllable fabrication of mesoporous carbon nanoparticles (MCNs) with tunable pore structures is of great interest, due to the remarkable effect of pore structure on electrochemical performance o...

Oxidized Black Phosphorus Nanosheets as an Inorganic Antiresorptive Agent

Black phosphorus (BP) is a newly discovered two-dimensional material that has promising applications from bioelectronics to biomedicine. However, facile oxidation of BP leads to changes in surface ...

Tunable luminescence of Eu3+ -activated CaWO4 nanophosphors via Bi3+ incorporation.

A series of CaWO4 :3Eu3+ :xBi3+ (x = 2, 5, 7 and 10 at.%) nanophosphors was prepared through the efficient low-temperature ethylene glycol route. Their structural, as well as photophysical, properties were studied. X-ray diffraction analysis and a X-ray photoelectron spectroscopy survey confirmed that the Bi3+ and Eu3+ ions incorporated perfectly into Ca2+ and without disturbing the lattice. The samples exhibited almost spherical morphology with average particle sizes from 10 to 30 nm. For the nanoparticles, Fourier transform infrared spectroscopy featured broad absorption bands around 871 and 778 cm-1 that were due to antisymmetric stretching, whereas a peak at 435 cm-1 was assigned to antisymmetric bending vibrations of the bonds in [WO4 2- ] clusters. The nanophosphors showed orange-red luminescence, which was further tuned to red by incorporation of sensitizer Bi3+ ions. This colour tuning of the nanoparticles is described in the context of energy transfer from the WO4 2- group to sensitizer Bi3+ and activator Eu3+ ions under 394 nm excitation. A CIE diagram supports this colour tunability.

Vermiculite modification increases carbon retention and stability of rice straw biochar at different carbonization temperatures

Biochar is considered a promising material for sequestering CO2 from the atmosphere, thus helping to alleviate climate change when returned to the soil. Biochar stability is the most decisive factor determining its C sequestration potential. Mineral modification may improve biochar characteristics, but systematic research on the effect of mineral modification on the C retention and stability of biochar and the associated mechanisms is limited. Therefore, in this study, rice straw was used to produce biochar at various temperatures (300, 400, 500, 600, and 700 °C), with vermiculite as a modified mineral material. Several methods including thermogravimetric analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance (NMR) spectroscopy were used to evaluate the effect of vermiculite modification and carbonization temperature on biochar stability. Biochar yield and C retention ratio decreased with increasing temperatures but increased by 13.5–38.8% and 5.2–22.1%, respectively, after vermiculite modification. The ratios of C thermal weight loss, atomic H/C, and C oxidation loss in the biochar were reduced with increasing carbonization temperature, indicating improved thermal, aromatization, and chemical oxidation stability. A trade-off that did not compromise C sequestration potential was optimized at 700 and 600 °C for the unmodified and modified biochar, respectively. Furthermore, the total mineral content of the biochar, particularly Fe, Al, Mg, and Si, were increased by vermiculite modification. FTIR results showed that chemical bonds, such as Si–O–C and Fe–O, were formed or enhanced on the biochar surface after vermiculite modification. This was further certified by the XPS survey spectra. NMR results indicated that biochar stability was enhanced by increasing the aromatization rate during carbonization, that is, by the conversion of C from alkyl and carbonyl C to aromatic C. This study provides a basis for research into and the development of functional biochar and its application in C sequestration.

Improved accumulation of TGF-β by photopolymerized chitosan/silk protein bio-hydrogel matrix to improve differentiations of mesenchymal stem cells in articular cartilage tissue regeneration

Articular cartilage regeneration is a challenging process due to its inadequate ability of self-recovering biological mechanisms. The progresses of cartilage tissue engineering is supported to overwhelmed the repairing difficulties and degenerative diseases. The main goal of the present study is to design biomaterials with suitable physico-chemical, mechanical and biological properties for the carrier of growth factor and improving differentiation of mesenchymal stem cell into damaged cartilage tissues. Herein, TGF-β loaded hydrogel network was prepared through the chemical interactions between vinyl group of natural polymers. Fourier-transform infrared spectroscopy results show the characteristic peaks at 3074 cm−1, 1713 cm−1, and 810 cm−1, which confirm the existence of the vinyl group and successful formation of maleoyl functionalized Chitosan (MCh). The obtained MCh was freely dissolved in the distilled water up to 8% (w/v). X-ray photoelectron spectroscopy survey spectral results show a peak at 289.0 eV which revealed that the OCO and DS were 1.2% and also evidenced the methacryl substitution of Silk fibroin (SF) nanoformulations. The weight loss and mechanical test were analyzed and the results showed that MSF acts as a foremost crosslinking point with MCh through the reaction between the methacrylate groups of MSF and maleoyl groups of MCh which led to enhancing the density and improved the compressive strength. The maximum drug release activity was recorded in the TGF-β loaded MCh@MSF hydrogel compared to bare MCh hydrogel. Further, the TGF-β loaded MCh@ MSF hydrogel exhibited the cell viability percentage nearly at 79–102% for MC3T3-E1 and 88–104% for BMDSCs. Similarly, the TGF-β loaded MCh@MSF exhibited the highest inhibitory activity against E. coli (83%) than S. aureus (67%). Overall, this study concluded the TGF-β loaded MCh@MSF showed better biocompatibility and could be utilized in the field of cartilage tissue engineering.

Interaction between perfluorooctanoic acid and aerobic granular sludge

The increasing use of perfluorooctanoic acid (PFOA) raises concerns about its potential toxicity to the environment. However, the interaction between PFOA and aerobic granular sludge has never been documented. This work therefore aims to provide such support through investigating the fate of PFOA at environmentally relevant levels in aerobic granular sludge systems and its impact on aerobic granular sludge. Experimental results showed that 32.0%∼36.4% of wastewater PFOA was removed by aerobic granular sludge in stable operation when PFOA concentration was ranged from 0.1 to 1.0 mg/L. Mass balance analyses and X-ray photoelectron spectroscopy survey scan revealed that the removal of PFOA was dominated by adsorption rather than biodegradation, and sorption kinetic analysis indicated that inhomogeneous multilayer adsorption was responsible for this removal. The adsorbed PFOA deteriorated the settleability of granular sludge and biological nitrogen and phosphorus removal significantly. Experimental results showed that 1.0 mg/L PFOA inhibited anaerobic phosphate release, aerobic phosphate uptake, nitrate reduction, and nitrite reduction processes by 60%, 50%, 13.1%, and 5.8%, respectively. It was observed that PFOA induced large amounts of filamentous villus growing on the surface and increased the extracellular polymeric substances of granular sludge. Fourier-transform infrared spectra and X-ray photoelectron spectroscopy spectrum showed that several function groups in extracellular polymeric substances such as hydroxyl groups, amides and polysaccharides were affected by PFOA. It was also found that PFOA inhibited the cyclic transformations of polyhydroxyalkanoates and glycogen. Microbial community analyses showed that PFOA decreased the abundances of Nitrosomonas, Nitrospira, Accumulibacter, and other function microbes such as Rhodospirillaceae, Thauera, and Azoarcus.

Covalently γ-aminobutyric acid-functionalized carbon nanotubes: improved compatibility with PHBV matrix

The improvement of compatibility between carbon nanotubes (CNTs) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was achieved using CNT functionalized with γ-aminobutyric acid (GABA). The efficiency of the CNT functionalization with GABA was evaluated by X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FT-IR), Raman spectroscopy, and transmission electron microscopy (TEM). The PHBV/CNT nanocomposites were produced in the molten state with the addition of 0.5 wt% of CNT (pristine, oxidized and functionalized with GABA) and characterized concerning the Izod impact strength tests. The impact fracture morphologies were analyzed using scanning electron microscopy. The results showed that GABA was covalently attached to CNT, resulting in the detection of nitrogen in the XPS survey, the shift of carbonyl peak wavelength on FT-IR, and a higher degree of structural disorder, detected by Raman and observed in TEM images. The impact strength was not significantly affected by the introduction of CNT; however, the impact fracture mechanism was changed from fragile to ductile when CNT was functionalized with GABA. These results are promising for the production of environmentally friendly nanocomposites with superior properties.

Characterization of carbonate fraction of the Atlantic bluefin tuna fin spine bone matrix for stable isotope analysis.

The mineral component of fish otoliths (ear bones), which is aragonitic calcium carbonate (CaCO3), makes this structure the preferred sample choice for measuring biological carbon and oxygen-stable isotopes in order to address fundamental questions in fish ecology and fisheries science. The main drawback is that the removal of otoliths requires sacrificing the specimen, which is particularly impractical for endangered and commercially valuable species such as Atlantic bluefin tuna (Thunnus thynnus) (ABFT). This study explores the suitability of using the first dorsal fin spine bone of ABFT as a non-lethal alternative to otolith analysis or as a complementary hard structure. The fin spines of freshly caught ABFT were collected to identify carbonate ions within the mineral matrix (i.e., hydroxyapatite) and to determine the nature of the carbonate substitution within the crystal lattice, knowledge which is crucial for correct measurement and ecological interpretation of oxygen and carbon stable isotopes of carbonates. Fin spine sections were analyzed via X-ray Photoelectron Spectroscopy (XPS), Raman Spectroscopy, and Fourier Transform InfraRed (FTIR). The XPS survey analysis showed signals of Ca, O, and P (three compositional elements that comprise hydroxyapatite). The Raman and FTIR techniques showed evidence of carbonate ions within the hydroxyapatite matrix, with the IR spectra being the most powerful for identifying the type B carbonate substitution as shown by the carbonate band in the v2 CO32− domain at ∼872 cm−1. The results of this study confirmed the presence of carbonate ions within the mineral matrix of the fin spine bone of ABFT, showing the feasibility of using this calcified structure for analysis of stable isotopes. Overall, our findings will facilitate new approaches to safeguarding commercially valuable and endangered/protected fish species and will open new research avenues to improve fisheries management and species conservation strategies.

Structural and magnetic properties of Gd–Zn substituted M-type Ba–Sr hexaferrites by sol-gel auto-combustion method

This work is report on Gd–Zn substituted M-type Ba–Sr hexaferrites with Ba0.5Sr0.5-xGdxFe12.0-xZnxO19 (0.0 ≤ x ≤ 0.4) by sol-gel auto-combustion method. X-ray diffractometer (XRD), Fourier transformer infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS) and Quantum Design measurement system (SQUID) were used to characterize M-type Ba–Sr hexaferrites. The results of X-ray patterns showed that the single M-type hexaferrite phase can be obtained when x = 0.00–0.20, however the impurity phase (α-Fe2O3) was observed for the hexaferrites with Gd–Zn content (x) ≥ 0.30. FT-IR frequency bands in the range (581–592) cm−1 and (431–442) cm−1 corresponded to the formation of tetrahedral and octahedral clusters of metal oxides in the hexaferrites, respectively. XPS survey showed that hexagonal crystal structure was formed completely, which was correlated closely with the results of XRD patterns and FT-IR spectra. SEM revealed the shape of the hexagonal plate. Measurements of the magnetization versus the field M(H) of Ba0.5Sr0.5-xGdxFe12.0-xZnxO19 (0.0 ≤ x ≤ 0.4) hexaferrites were conducted at 5 and 300 K. Zero field cooling (ZFC) and field cooled (FC) measurement data did not show blocking temperature peak, indicating the ferrimagnetic behavior of prepared hexaferrites. Moreover, at low temperatures a spin glass behavior was observed. The squareness ratio (Mr/Ms) indicated the uniaxial anisotropy for various hexaferrites. The deduced values of saturation magnetization (Ms), the magneton number (nB) and the effective magnetic anisotropy constant (Keff) decreased, whereas the values of the anisotropy fields (Ha) and the coercive field (Hc) increased with increasing Gd–Zn content at both 5 and 300 K.

Failure analysis of a field brittle fracture composite insulator: characterisation by X‐ray photoelectron spectroscopy analysis

In the present work, a field brittle fracture composite insulator was collected and examined with the purpose of obtaining a better understanding of the failure features. Firstly, the macroscopic and microscopic fractography of this fractured composite insulator was observed confirming that the classical brittle fracture morphology features appeared in this field failed composite insulator. Secondly, the X-ray photoelectron spectroscopy (XPS) analysis was performed on the fracture surface of the glass-fibre-reinforced polymer rod. By examining the XPS survey spectra and high-resolution XPS spectra for nitrogen, sulphur, silicon, calcium, aluminium, boron and carbon elements, the type of the glass fibre and the acid source responsible for this brittle fracture composite insulator were confirmed. Furthermore, the oxidation of the silicate network of glass fibre at the fracture surface was first observed, meanwhile, the oxidation of the epoxy resin matrix was also observed. The leaching of non-silicate constituents leading to a high-silica glass fibre was also observed; moreover, in comparison with the calcium and aluminium elements, the boron element resides in the silicate network was more preferential to be leached. The present work provides an insight into the brittle fracture in high voltage composite insulator from chemical properties point of view.

PHYSICOCHEMICAL CHARACTERISTICS OF RASAMANIKYA-AN AYURVEDIC ARSENICAL FORMULATION

Objective: The objective of this study was standardization and Chemical characterization of rasamanikya prepared as per standard operating procedures (SOP) mentioned in the classical text.
 Methods: Rasamanikya was prepared by putting churnodaka shodhita haratala (Orpiment-As2S3) between two abhraka (white mica) sheets which are heated for a while to obtain a red colored finished product. The Ayurvedic specifications for the analysis of rasamanikya were performed through qualitative and quantitative analysis. Physicochemical analysis, assay of elements by atomic absorption spectrometer (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were carried out and some other tests such as x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray analyzer (EDAX) were also performed to ensure the quality of the drug.
 Results: In the finished drug Arsenic and Sulphur are present in the form of As4S4, As2S3, As2S5. On the basis of XPS survey scans, scanning electron microscopy-energy dispersive x-ray analyzer (SEM-EDAX) and carbon, hydrogen, nitrogen, sulphur (CHNS) analysis the Arsenic to Sulphur (As to S) ratio is thus standardized as 39-47: 53-61. In addition to this powder, XRD shows a major conversion into an amorphous phase.
 Conclusion: The results could be used to lay down a new set of pharmacopoeial standards for the preparation of rasamanikya for getting optimal efficacy of medicine. Therefore, the information will help the Scientists and Researchers to build comprehensive standards, to screen the compounds responsible for different bioactivities, and to elucidate the molecular mechanism of action.

X-ray photoelectron spectroscopy (XPS) study of Heusler alloy (Co2FeAl) interfaced with semiconductor (n-Si) structure

Abstract Layered magnetic heterostructures are very promising candidates in spintronics in which the influences of interfaces, surfaces and defects play a crucial role. X-ray photoelectron spectroscopy (XPS) study has been performed for studying in detail the chemical state and electronic structure of Co2FeAl (CFA) Heusler alloy interfaced with Si substrates. XPS survey scan spectra have clearly shown the presence of Fe, Co and Al signal along with the signal due to Si. The presence of Co, Fe and Al signal confirms the formation of CFA alloy phase. Our XPS results support our previous study [1] on CFA/Si structure in determining the magnetic and transport properties across the interface.

Effects of enzyme treatment on surface properties of Mg(OH)2-based peroxide bleached deinked pulp

Enzyme (laccase/mediator or lipase) treatment, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) surface analysis techniques were combined to explore the surface properties of Mg(OH)2-based peroxide bleached DIP (deinked pulp). The XPS survey spectra and SEM images showed that some trace elements, such as calcium, silicon, and aluminum, were present on the sample surface, in addition to the main elements, carbon and oxygen. The surface of enzyme-treated pulp was covered by the precipitated lignin or extractives. However, when the enzyme-treated pulps were bleached, the amount of precipitated lignin or extractives was considerably reduced. Lipase-treated, bleached pulp had better physical properties and lower effective residual ink concentration (ERIC) values than laccase/mediator-treated bleached pulp, which further indicated that lipase not only removed surface lignin and extractives, but it also was able to remove more residual ink contaminants.

Selective adsorption and recovery of precious metal ions from water and metallurgical slag by polymer brush graphene–polyurethane composite

Achieving flexible composite materials with high selectivity and adsorption capacity for gold and platinum group elements remains a challenging endeavor. In this study, a series of polyurethane foam (PUF) composites was synthesized using PUF as matrix. Scanning electron microscopy, Raman spectra, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy survey spectra, contact angle, and Brunauer–Emmett–Teller specific surface area were used for characterization. Solid-phase extraction of precious metal ions from acidic chloride solutions was performed via batch experiments. Results showed that cysteine polymer brush-grafted PDA@GPUF (poly-Cys-g-PDA@GPUF) contained a high concentration of hydroxyl, imine, and thiol groups on the surface, which endowed the composite with high separation performance for Au(III), Pd(II), Pt(IV), and Ru(III). Batch adsorption studies for poly-Cys-g-PDA@GPUF were performed with various parameters, such as solution pH, contact time, initial metal ion concentration, and temperature. The maximum adsorption capacity was found at pH 0 for Au(III), Pd(II), and Pt(IV) and at pH 3.0 for Ru(III). Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models were applied to analyze the experimental data. The best interpretation for the experimental data was given by the Langmuir isotherm. The effects of solution acidity, contact time, initial concentration of metal ions, temperature, coexisting ions, and recovery behavior were reported. Pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to determine the kinetic data. The pseudo-second-order kinetic model fitted the experimental data. Thermodynamic parameters, such as enthalpy (ΔH0), Gibbs' free energy (ΔG0), and entropy (ΔS0), were calculated for poly-Cys-g-PDA@GPUF. Poly-Cys-g-PDA@GPUF as solid-phase extractant was successfully applied for the preconcentration of Au(III), Pd(II), Pt(IV), and Ru(III) in aqueous samples, metallurgical slag, and certified sample with satisfactory results.

Tutorial on interpreting x-ray photoelectron spectroscopy survey spectra: Questions and answers on spectra from the atomic layer deposition of Al2O3 on silicon

X-ray photoelectron spectroscopy (XPS) has become the most widely used method for chemically analyzing surfaces. In XPS, photoelectrons are generated by irradiating a surface with x rays. As the importance and popularity of XPS have grown, it has drawn users without significant XPS experience, and incorrect and incomplete interpretations of XPS spectra regularly appear in the literature. This tutorial is designed as a tool to guide less experienced users in analyzing XPS survey spectra. Here, the authors examine a series of XPS survey spectra collected during the atomic layer deposition (ALD) of Al2O3 from trimethylaluminum and water precursors. Prior to this, brief explanations of XPS and ALD are presented. This tutorial is structured as a series of questions and answers that the interested reader may choose to engage in. The XPS spectra are scrutinized to extract information about the elements present in the film, the presence of contamination, and the nature of the film growth process. The questions and answers in this tutorial address important fundamental issues common to the interpretation of many XPS survey spectra in the context of ALD.

Initial stages in functionalization of polystyrene upon treatment with oxygen plasma late flowing afterglow

A remote microwave discharge was applied as a source of oxygen (O) atoms for treatment of polystyrene in the preparation chamber of an x-ray photoelectron spectroscopy (XPS) instrument. The density of O atoms as measured with a calibrated catalytic probe was 2 × 1018 m−3. Such a small O atom density allowed for investigating the initial stages of polymer functionalization. The samples were subjected to various fluences of O atoms from approximately 2 × 1021 to 3 × 1023 m−2, and the functional groups were determined by XPS without breaking vacuum conditions. The results showed rapid destruction of the aromatic rings even at low O atom fluences. The initial functionalization caused the formation of hydroxyl groups followed by carbonyl groups, but the measurable amount of the carboxyl or ester groups, let alone carbonate, appeared only after the fluence of approximately 1 × 1022 m−2. The concentration of functional groups of the high XPS binding energy shift increased at elevated fluences until it became comparable with those of the low energy shift at the largest fluence used in this investigation, i.e. 3 × 1023 m−2. The O concentration on the polymer surface as determined from XPS survey spectra was first rapidly increasing up to the fluence of a few 1022 m−2 and then continue increasing slowly with the increasing fluence even beyond 1 × 1023 m−2. This investigation, which was performed in situ, gives us new knowledge for understanding the initial steps of polymer functionalization.

Substrate temperature effects on structural and photoelectric properties of CdS thin films

Cadmium sulfide thin films were deposited on quartz substrates by magnetron sputtering method with varying substrate temperatures. X-ray diffraction patterns of prepared samples showed preferred orientation of (002) with pure hexagonal phase. Atomic force microscopy and scanning electron microscopy images exhibited a surface morphology with uniform and homogeneous grains. X-ray photoelectron spectroscopy (XPS) revealed peaks corresponding to cadmium, sulfur, carbon and oxygen atoms, and the high-resolution XPS surveys for cadmium 3d and sulfur 2p showed an obvious shift to lower binding energy as the substrate temperature raised. Meanwhile, the optical absorption coefficient gradually increased, and the transmittance was approximately 75%. The optical energy gap was as high as 2·40 eV at the substrate temperature of 200°C. Photoconductivity curves presented a rapid response, the lowest conductivity at steady state (only 1·6257 × 10−4 Ω−1 cm−1) and a high solar photoconductivity gain (G p = 296·36) at substrate temperatures of up to 200°C.

Combined TEM and XPS studies of metal - polymer interfaces for space applications

The stability of metal-polymer interfaces after extreme thermal cycling is essential for high-performance thermal insulation of satellites. The Aluminium-Polyimide (Al-PI) system investigated here is used as a multilayer insulator for satellites currently in low earth orbit. Its interfacial adhesion should be resistant to thermal loading caused by the sun during orbit. In this study, transmission electron microscopy (TEM) is combined with X-ray photoelectron spectroscopy (XPS) to relate the interface structure and chemistry to the mechanical strength of the Al-PI interface as a function of thermal cycling. Results show that the interfacial properties of Al-PI remain unaffected by thermal cycling of ±150°C in gaseous nitrogen up to 200 thermal cycles. TEM cross-sections were used to examine the interface structure and revealed a 3.6nm, amorphous interlayer between Al and PI for as deposited and cycled samples. XPS survey scans and relevant high resolution core levels were recorded on both sides of the interface to identify and understand relevant interfacial bonding as well as to distinguish between adhesive failure at the interface and cohesive failure in the polyimide substrate. The Al-PI system presented in this study can serve as a model for strong and thermally resistant metal-polymer interfaces. The combination of interface strength, structure and chemistry allows for an improved understanding of how thermal treatments can influence interfacial behaviour between metals and polymers and will help improve design and reliability of materials used in space as well as terrestrial applications.

Spectroscopic Investigation of Interfacial Interaction of Manganese Oxide with Triclosan, Aniline, and Phenol

We investigated the reaction of manganese oxide [MnOx(s)] with phenol, aniline, and triclosan in batch experiments using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and aqueous chemistry measurements. Analyses of XPS high-resolution spectra suggest that the Mn(III) content increased 8-10% and the content of Mn(II) increased 12-15% in the surface of reacted MnOx(s) compared to the control, indicating that the oxidation of organic compounds causes the reduction of MnOx(s). Fitting of C 1s XPS spectra suggests an increase in the number of aromatic and aliphatic bonds for MnOx(s) reacted with organic compounds. The presence of 2.7% Cl in the MnOx(s) surface after reaction with triclosan was detected by XPS survey scans, while no Cl was detected in MnOx-phenol, MnOx-aniline, and MnOx-control. Raman spectra confirm the increased intensity of carbon features in MnOx(s) samples that reacted with organic compounds compared to unreacted MnOx(s). These spectroscopy results indicate that phenol, aniline, triclosan, and related byproducts are associated with the surface of MnOx(s)-reacted samples. The results from this research contribute to a better understanding of interactions between MnOx(s) and organic compounds that are relevant to natural and engineered environments.

Structural and morphological characterization of Al2O3 coated macro-porous silicon by atomic layer deposition

In the present study, Al2O3 coated on macro-porous silicon (m-PS) is prepared by atomic layer deposition (ALD) whereas m-PS is prepared by electrochemical anodization of P type silicon (100) with current density of 15mA/cm2. Field emission scanning electron microscopy analysis shows Al2O3 nanoparticles with size of ~100nm are conformally coated on m-PS. The surface chemistry and formation mechanism of ALD of Al2O3 (ALD-Al2O3) on m-PS are demonstrated in detail. Optical profilometer results of Al2O3/m-PS confirm conformality of Al2O3 coating on m-PS because the surface amplitude parameter values of m-PS are decreased after ALD-Al2O3. Fourier Transform Infrared analysis confirms that unstable Si-H species of m-PS are replaced with stable Si-Al species. X-ray photoelectron spectroscopy (XPS) analysis of Al2O3/m-PS is carried out for chemical analysis and band gap energy measurement of Al2O3. The XPS survey spectrum shows that fluorine peak is also evolved along with Al, O and C elements which confirm that m-PS surface consists of fluorine. The band gap energy of Al2O3 coating is calculated as 6.91eV from analysis of high resolution O 1s spectrum.