Reduction Of SnO2 Research Articles

Efficient Sn Recovery from SnO2 by Alkane (CxHy=2x+2, 0\u2009\u2264\u2009x\u2009\u2264\u20094) Reduction

We study the mechanism of alkane reduction of SnO2 for efficient low-temperature recovery of Sn from SnO2. Based on thermodynamic simulation results, we comparatively analyze the reduction behavior and the efficiency of SnO2 reduction by H2 and alkanes (CxHy=2x+2, 0 ≤ x ≤ 4). We found that alkanes (n·CxHy) with the higher nx generally complete the reduction of SnO2 (T100) at the lower temperature. Moreover, the T100 of the SnO2 reduction by alkanes (n·CxHy) was decreased from the T100 of pure hydrogen with the same amount of hydrogen atoms (n·Hy). We found that the concentration of a gas phase product mixture, the amount of the produced solid carbon, and the T100 complementary vary as a function of the nx and ny, the total amount of carbon and hydrogen atoms in the reducing gas phase molecules. Our results demonstrate a viability of the low temperature reduction method of SnO2 by alkanes for efficient recovery of Sn from SnO2, which can be applied for Sn recovery from Sn containing industrial wastes or Sn ores with economic value added that is held by the co-produced H2.

Reduced graphene oxide (RGO)-SnOx (x=0,1,2) nanocomposite as high performance anode material for lithium-ion batteries

Although, metal oxide-graphene nanocomposites and their applications in Li ion battery is a subject of intense investigation over the years, the synthesis of the composite that often needs high temperature processing along with expensive equipment are the major issues to overcome. We demonstrate a facile, low cost and room temperature synthesis of SnOX (x = 0,1,2) - reduced graphene oxide (RGO) nanocomposite where concurrent formation of SnO2, reduction of SnO2 to SnOx nanoparticles and graphene oxide to reduced graphene oxide takes place in one pot in-situ chemical reduction process. Concentration of the reducing agent (NaBH4, 0 mol–0.06 mol) is varied to examine the effect on the formation of the nanocomposite as well as their electrochemical performance. The RGO-SnOx nanocomposite prepared by using 0.04 mol of reducing agent reveal better Li storage performance, stable capacitance (833 mAh g−1 after 50 cycles, 767 mAh g−1 after 100 cycles, current rate = 100 mA g−1), and good rate capability (481 mAh g−1 at ∼1 A g−1). The lithium ion diffusion coefficient of RGO-SnOx (0.04 mol) nanocomposite is estimated as 2.4 × 10−10 m2s−1 that is one/two order higher than other RGO-SnOx nanocomposites which promotes the Li ion transport in the composite. The synthesis procedure has a strong potential to be one of the universal method for the preparation of a variety of composites by the suitable variant in the synthesis protocol.

Stability of Fluorine Doped Tin Oxide (FTO) Coated Substrates Under Extreme Polarization Conditions

Fluorine doped tin oxide (FTO) is a transparent conducting oxide which is widely used in different applications ranging from sensors, digital displays, smart window coatings, catalysts supports, and electrode substrates for various electrochemical applications. The FTO coated glass slides were evaluated for their chemical stability in different pH solutions at room temperature by carrying out potentiodynamic polarization and cyclic voltammetry (CV). Accelerated stress tests were carried out in 0.1 M HCl and 0.1 M NaOH solutions by scanning the potential from -2 V to 2 VRHE at a scan rate of 1 V/s. Ex-situ vibrational spectroscopy and in-situ photo absorption spectroscopy were carried out to evaluate the material degradation when electrochemically polarized. The FTO was more stable in 0.1 M HNO3 and 0.1 M NaCl solutions under both anodic and cathodic polarization conditions. Oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) were the cathodic reactions observed during cathodic polarization of the FTO. The activity of FTO for HER was higher in the acidic solutions than that in the neutral or alkaline solutions. Cathodic polarization in 0.1 M HCl solution resulted in a reduction of SnO2 to lower valent species. The semiconductivity of FTO, which was n-type at low anodic potentials, was p-type at high anodic potentials possibly due to the formation of a SnO-type surface layer by the removal of lattice oxygen during the oxygen evolution reaction. Cyclic stability of the FTO was evaluated by conducting CV between -2.0 and vbn 2.0 VAg/AgCl at 1 V/s. Intergranular corrosion was observed and the stability was completely lost after 215 cycles in the 0.1 M HCl solution, as seen in Fig. 1. The stability of FTO was better in the 0.1 M NaOH solution, wherein the electro-catalytic activity degraded after 500 cycles, the electrical connectivity was maintained even after 4500 cycles. Figure 1

Theoretical assessment of hydrogen production and multicycle energy conversion via solar thermochemical cycle based on nonvolatile SnO2

Abstract A kind of solar thermochemical cycle based on methanothermal reduction of SnO2 is proposed for H2 and CO production. We find that the oxygen release capacity and thermodynamic driven force for methanothermal reduction of SnO2 are large, and suggest CH4:SnO2=2:1 as the feasible reduction condition for achieving high purities of syngas and avoiding vaporization of produced Sn. Subsequently, the amount of H2 and energetic upgrade factors under different oxidation conditions are compared, in which excess water vapor is found beneficial for hydrogen production and fuel energetic upgradation. Moreover, the effect of incomplete recovery of SnO2 on the subsequent cycle is underscored and explained. After accounting for factors such as isothermal operation and cycle stability, CH4:SnO2=2:1 and H2O:Sn=4:1 are suggested for highest solar-to-fuel efficiency of 46.1% at nonisothermal condition, where the reduction and oxidation temperature are 1400 and 600 K, respectively.

Toward Phase and Catalysis Control: Tracking the Formation of Intermetallic Nanoparticles at Atomic Scale

Summary Intermetallic nanoparticles (iNPs) have yielded enormous successes in catalytic applications by the formation of ordered phases. However, atomic-level understanding of the alloying mechanism, which plays a pivotal role in controlling intermetallic phases and tailoring their catalytic properties, is still elusive. In this study, we discovered a consecutive formation of ordered Pt3Sn and PtSn phases during the growth of Pt-Sn iNP inside a well-defined nano-reactor at elevated temperature by using in situ scanning transmission electron microscopy. We found that the surface-mediated diffusion of Sn controls overall dynamics of the reaction, while the unique coherent interfacial structure is determinative for the PtSn transformation. We then further controlled the phase selection of Pt-Sn iNPs and demonstrated their distinguishable catalytic behaviors. Our findings not only provide detailed experimental evidence on the alloying mechanism in intermetallic nanoscale systems but also pave the way for mechanistic control of synthesis and catalytic properties of iNPs.

Reduction behavior of Tin-containing phase in Tin-bearing iron concentrates under CO-CO2 mixed gases

The main purpose of this study was to ascertain the reduction behavior of tin phase (SnO2) in tin-bearing iron concentrates at the respective temperature of 1273 and 1373 K in diverse CO-CO2 mixed gases using chemical analysis, XRD, and SEMEDS analysis. The results show that the reduction behavior of SnO2 depends on the roasting temperature and CO content. At 1273 K, the SnO2 will be reduced to Sn (l) with the CO content being higher than 17.26 vol%, and there is no formation of SnO(s). With the temperature increased to 1373 K, the SnO2 is reduced stepwise in the order to form SnO2 ? SnO (l) ? Sn(l) with CO content over 15.75 vol%. The kinetic study shows that activation energy of the reaction SnO2(s)+CO(g)=Sn(l)+ CO2(g) is 144.75 kJ/mol at 1073-1223 K, being far lower than the one in the reduction of SnO2(s) into SnO(g) at 1273-1323 K, which leads to a conclusion that the tin in tin-bearing iron concentrates could be removed effectively after the Sn(l) sulfurated into SnS at relatively lower temperatures (1073-1223 K) using the sulfidation roasting method.

Electrochemical Stability of Fluorine Doped Tin Oxide (FTO) Coating at Different pH Conditions

Fluorine doped tin oxide coated glass slides were evaluated for their chemical stability in different pH solutions at room temperature by carrying out potentiodynamic polarization and cyclic voltammetry (CV). The FTO was more stable in 0.1 M HNO3 and 0.1 M NaCl solutions under both anodic and cathodic polarization conditions. Cathodic polarization in 0.1 M HCl solution resulted in a reduction of SnO2 to lower valent species. The semiconductivity of FTO, which was n-type at low anodic potentials, was p-type at high anodic potentials possibly due to the formation of a SnO-type surface layer by the removal of lattice oxygen during the oxygen evolution reaction. Cyclic stability of the FTO was evaluated by conducting CV between −2.0 and vbn 2.0 VAg/AgCl at 1 V/s. Intergranular corrosion was observed and the stability was completely lost after 215 cycles in the 0.1 M HCl solution. The stability of FTO was better in the 0.1 M NaOH solution, wherein the electro-catalytic activity degraded after 500 cycles, the electrical connectivity was maintained even after 4500 cycles.

Reduction of SnO2 by a Mixed Gas of Methane and Hydrogen

We investigate the reduction of SnO2 and the generation of syngas(H2, CO) using methane(CH4) and hydrogen(H2) or a mixed gas of methane and hydrogen as a reducing gas. When methane is used as a reducing gas, carbon is formed by the decomposition of methane on the reduced Sn surface, and the amount of generated carbon increases as the amount and time of the supply of methane increases. However, when hydrogen is used as a reducing gas, carbon is not generated. High purity Sn of 99.8 % and a high recovery rate of Sn of 93 % are obtained under all conditions. The effects of reducing gas species and the gas mixing ratio on the purity and recovery of Sn are not significantly different, but hydrogen is somewhat more effective in increasing the purity and recovery rate of Sn than methane. When 1 mole of methane and 1 mole of hydrogen are mixed, a product gas with an H2/CO value of 2, which is known to be most useful as syngas, is obtained.

Off-current reduction in p-type SnO thin film transistors

SnO is one of the few candidates for p-type oxide thin film transistors (TFTs) because it retains a reasonable high hole mobility in a nanocrystalline film. However, the high off-current of SnO TFT limits its usefulness. In this work, SnO TFTs were fabricated using thermal evaporation under ultra-high vacuum. In order to decrease the off-current in p-type SnO thin film transistors (TFTs), we used yttrium to reduce n-type minority charges in the channel. The on/off ratio of the TFT increases from 102 to 5 × 104 and the mobility of the TFT in the saturated regime reduces from 1.6 to 1.4 cm2/V s when the SnO channel is doped with 1 wt. % of Y. Grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy reveal that the reduction of SnO2 in the Y-doped SnO TFT channel is the main reason for the improvement in the TFT characteristics.

Modification of the Amount of CH4 Supplied for the Efficient CH4 Reduction of SnO2

The methane reduction (MR) of SnO 2 has been proposed as a highly efficient method for recovering Sn from SnO 2 containing industrial wastes. The MR of SnO 2 also produces a mixture of H2 and CO, which can be further utilized as a syngas for the production of various fuels through the Fisher-Tropsch process. To optimize the process parameters, we studied the effect of the amount of supplied CH4 (CH4/SnO 2 molar ratios of 1, 3, or 5) on the recovery of Sn from SnO 2 and the H2/CO ratio in the produced gas. Through a combination of thermodynamic simulation and experimental confirmation, we found that the recovery rate of Sn, and the molar ratio of H2/CO in the product gas, increased as a function of the supplied-CH4/SnO 2 ratio. We found that the recovery of Sn increased as a function of supplied-CH4 (95.5% at CH4/SnO 2 =5) however, the purity of Sn was consistent for all studied samples (~99.90%). Our results confirm that 3N quality highpurity Sn can be easily recovered from SnO 2 containing industrial wastes by direct solid-gas reduction.

Anti-reductive properties of AZO/FTO bilayered transparent conducting films

ABSTRACTAluminium-doped zinc oxide (AZO)/fluorine-doped tin dioxide (FTO) double-layered transparent conducting films were manufactured on quartz glass substrates by spray pyrolysis. Like top films, AZO has marvellous reduction-resistant properties during a-Si:H deposition. However, as thin films with features of self-textured surfaces, SnO2:F (FTO) provides high light scattering for front electrode in photovoltaic devices. The distribution of elements in surface and interface has been analysed by glow discharge spectrometer. The anti-reductive behaviour in ambient hydrogen plasma condition was studied and the results showed that hydrogen ions are dispersed in the AZO layer but not diffused to the FTO layer, thus avoiding the reduction of SnO2 to SnO or Sn during hydrogen plasma bombardment. Besides, this phenomenon also indicated that the coating of the AZO layer on FTO electrode can increase the resistance of FTO to hydrogen. AZO film protects FTO from reduction, and the resistivity to hydrogen plasma of AZO/FTO bilayer films has been improved.

C/Sn/RGO Nanocomposites as Higher Initial Coulombic Efficiency Anode for Sodium‐Ion Batteries

AbstractTheoretically, metal Sn owns higher initial coulombic efficiency than SnO2 in the sodium‐ion batteries (SIBs). Metal Sn is commonly obtained by the thermal reduction of SnO2 at present. However, the uncontrollable growth of metal Sn particles during the reduction progress is a key challenge. In this work, a composite material of refined metal Sn particles (particle size about 20∼200 nm) and carbon buffer medium has been prepared by a novel method, which is simple thermal reduction adopted after the treatment of SnO2/RGO in the pitch kerosene solution. The results show that this method overcomes the uncontrollable growth of metal Sn particles. Electrochemical tests show that C/Sn/RGO possesses a higher initial reversible capacity of 476.2 mAh g−1, and a higher initial coulombic efficiency of 70.3%. This method would have wider applications for the attractive properties of Na‐ion batteries in the future.

Design of Reduction Process of SnO2 by CH4 for Efficient Sn Recovery

We design a novel method for the CH4 reduction of SnO2 for the efficient recovery of Sn from SnO2 through a study combining theory and experiment. The atomic-level process of CH4-SnO2 interaction and temperature-dependent reduction behavior of SnO2 were studied with a combination of a multi-scale computational method of thermodynamic simulations and density functional theory (DFT) calculations. We found that CH4 was a highly efficient and a versatile reducing agent, as the total reducing power of CH4 originates from the carbon and hydrogen of CH4, which sequentially reduce SnO2. Moreover, as a result of the CH4 reduction of SnO2, a mixture of CO and H2 was produced as a gas-phase product (syngas). The relative molar ratio of the produced gas-phase product was controllable by the reduction temperature and the amount of supplied CH4. The laboratory-scale experimental study confirmed that CH4 actively reduces SnO2, producing 99.34% high-purity Sn and H2 and CO. Our results present a novel method for an efficient, green, and economical recycling strategy for Sn with economic value added that is held by the co-produced clean energy source (syngas).

The determination of electrolyte stability and conditions for electrochromic WO3 films deposition

The present research is devoted to finding the condition and intricacies of WO3 film electrodeposition from peroxotungstic acid-based electrolyte that can be used for real production process. For deposition of electrochromic WO3 films, the galvanostatic regime with following parameters is proposed: cathodic current density -0.2 mA/cm2, deposition time 30 min. The films prepared under such deposition parameters are transparent and had good adhesion to the substrate – the glass coated with fluorine-doped tin oxide. The averaged coloration degree for film deposited from fresh electrolyte is 10%, while for film deposited from regenerated electrolyte – 5 %. During investigation, the potential window in which WO3 film could be colored and bleached, without reduction of SnO2 to metallic tin is established. It is also demonstrated that electrolytes containing peroxotungstic acid are unstable and degrade over time. It is proposed to use hydrogen peroxide for regeneration of electrolyte. It is demonstrated that electrolyte can be partially regenerated with hydrogen peroxide.

Overlapping and rate controlling electrochemical reactions for tin(IV) oxide electrodes in lithium-ion batteries

The results of this extensive electrochemical study of the electrochemical reactions of SnO2 electrodes in lithium-ion batteries demonstrate that the different reduction and oxidation reactions overlap significantly during the cycling and that the rates of the redox reactions are limited by the mass transport through the layers of oxidation or reduction products formed on the electrodes. The experiments, which were carried out in the absence and presence of the lithium alloy reactions, show that the capacity losses seen on the first cycles mainly can be explained by an incomplete oxidation of the lithium tin alloy and an incomplete reformation of SnO2. The latter can be explained by the formation of thin tin oxide layers (i.e., SnO and SnO2), protecting the remaining tin, as the oxidation current then becomes limited by the Li+ diffusion rate though these layers. The results, also show that the first cycle SnO2 reduction was incomplete for the about 20μm thick electrodes containing 1 to 6μm large SnO2 particles. This can be ascribed to the formation of a layer of tin and Li2O (protecting the remaining SnO2) during the reduction process. Although the regeneration of the SnO2 always was slower than the reduction of the SnO2, the results clearly show that the SnO2 conversion reaction is far from irreversible, particularly at low scan rates and increased temperatures. Electrochemical cycling at 60°C hence gave rise to increased capacities, but also a faster capacity loss, compared to at room temperature. These new findings indicate that a full utilization of SnO2 based electrodes at a given cycling rate only can be reached with sufficiently small particles since the allowed particle size is given by the time available for the mass transport through the formed surface layers. The present results consequently provide important insights into the phenomena limiting the use of SnO2 electrodes in lithium-ion batteries.

Phantom Electrons in Mesoporous Nanocrystalline SnO2 Thin Films with Cation-Dependent Reduction Onsets

Mesoporous thin films comprised of ∼15 nm diameter SnO2 nanocrystallites were synthesized and characterized in acetonitrile electrolytes by electrochemical and spectroscopic techniques. Spectroelectrochemical reduction of the thin films resulted in broad, non-superimposable UV/vis absorption changes. Simultaneous analysis of potential-dependent spectra, by a process termed “potential associated spectra”, resulted in the identification of three unique absorption spectra for reduced SnO2, while only one spectrum was identified for TiO2. Reduction of SnO2 resulted in the appearance of (1) a broad absorption that spans across the visible and near-IR regions, (2) a blue-shifted fundamental absorption, and (3) an absorption band in the blue region. The absorption onsets were dependent on the electrolyte cation, present as the perchlorate salt of Li+, Na+, Mg2+, Ca2+, and TBA+, where TBA+ is tetrabutylammonium. Correlations between the charge within the thin film and the absorbance intensity revealed that signif...

Formation mechanisms of Fe3\u2212xSnxO4 by a chemical vapor transport (CVT) process

Our former study reported that Fe-Sn spinel (Fe3−xSnxO4) was easily formed when SnO2 and Fe3O4 were roasted under CO-CO2 atmosphere at 900–1100 °C. However, the formation procedure is still unclear and there is a lack of theoretical research on the formation mechanism of the Fe-Sn spinel. In this work, the reaction mechanisms between SnO2 and Fe3O4 under CO-CO2 atmosphere were determined using XRD, VSM, SEM-EDS, XPS, etc. The results indicated that the formation of Fe3−xSnxO4 could be divided into four steps: reduction of SnO2 to solid phase SnO, volatilization of gaseous SnO, adsorption of gaseous SnO on the surface of Fe3O4, and redox reaction between SnO and Fe3O4. During the roasting process, part of Fe3+ in Fe3O4 was reduced to Fe2+ by gaseous SnO, and meanwhile Sn2+ was oxidized to Sn4+ and entered into Fe3−xSnxO4. The reaction between SnO2 and Fe3O4 could be summarized as Fe3O4 + xSnO(g) → Fe3−xSnxO4 (x = 0–1.0).

Thermodynamic analysis of solar driven SnO2/SnO based thermochemical water splitting cycle

There are many studies related on the SnO2/SnO based solar thermochemical water splitting cycle, however there are still no studies addressing on the detailed thermodynamic analysis of this process using HSC Chemistry software and its thermodynamic database. In this cycle, the first step belongs to the endothermic solar thermal reduction of SnO2 producing gaseous SnO and O2. The second step corresponds to the exothermic production of H2 via water splitting reaction using SnO produced in the first cycle, thereby regenerating SnO2 which can be recycled back to step 1. Thermodynamic equilibrium compositions associated with step 1 and 2 are identified as a function of reaction temperatures and partial pressures of O2 in the inert carrier gas. Furthermore, the thermodynamic efficiency analysis is performed by following the second law of thermodynamics to determine the cycle and solar-to-fuel energy conversion efficiencies associated with the SnO2/SnO based thermochemical water splitting cycle. Effects of thermal reduction and water splitting temperatures on various thermodynamic parameters are also investigated in detail. Obtained results indicate that the higher values of cycle efficiency (41.17%) and solar-to-fuel energy conversion efficiency (49.61%) are achievable by operating this cycle at a thermal reduction temperature of 1780K and water splitting temperature equal to 800K with 50% heat recuperation. This work gives a detailed thermodynamic and efficiency analysis of SnO2/SnO based two-step solar thermochemical water splitting cycle for hydrogen production.

Synthesis of Porous Sn4P3-C Nanospheres As an Ultra- Stable and High Capacity Anode Material for Sodium-Ion Battery

Owing to the fast development of portable electronics and electric vehicles, the need for electrochemical energy storage has increased. Among various electrochemical energy storage devices, lithium ion batteries (LIBs) have been demonstrated as one of the most successful examples in many electric applications. Because of their distinguished features, LIBs have high energy density and good power performance. However, due to its limited resource, its price will grow high if LIBs are progressively used. In this regard, sodium ion batteries (SIBs) have been considered as a promising alternative due to its abundance source in earth crust. Due to its similar insertion chemistry, sodium can directly transform well-established electrode materials in LIBs to SIBs. Unlimited efforts have been devoted to find new anode materials for high performance SIBs, including carbonaceous materials, metal oxides and sulfides, and alloy-based materials. Recently, elemental phosphorus P has been found to be electrochemically active for sodium ion battery anode, forming sodium phosphide (Na3P). It gives a high theoretical specific capacity of 2,597 mAh/g. But, its electrochemical performance is unsatisfactory because phosphorus has a very low electrical conductivity (~10-14 S/cm) and suffer from structural pulverization problem caused by its large volume change. To overcome this problem, Sn4P3 material has been reported as a promising anode for SIBs. It has been recently reported that Sn4P3 showed a synergistic Na-storage reaction where Sn and P atoms can react with Na to form Na15Sn4 and Na3P, and that the resulting Na15Sn4 alloy acts as a conducting pathway to activate the reversible Na-storage reaction of low electrical conductive Na3P particles. Also, Sn4P3 anode material exhibits a high reversible capacity of 1,230 mAh/g. The architecture of a stable and robust protective layer on the metallic Sn anode is critically important to ensure the good electrochemical performance of SIBs. Up to now, most of SIBs anodes consisting of elemental P and Sn alloys are generally produced by ball milling, thus the morphology has not been controlled. Ball milling method have been widely used as SnxPy electrodes because their phases can be easily controlled in laboratory scale synthesis. However, ball milling method for SnxPy is usually hard to control the morphology and produce nano scale, which leads to the deterioration of an active material resulting in capacity decay by several cycles. Therefore, hydrothermal method has received significant attention because it can control the nanoscale morphology for improved electrochemical performance. Herein, we report the porous Sn4P3-C nano spheres synthesized by hydrothermal process as an anode for SIB with an ultra-long term cycle stability and a high capacity. First, SnO2 nano spheres was synthesized by hydrothermal method with glucose precursor. Glucose not only prevents the rapid precipitation of colloidal SnO2 nano spheres but also serves as a carbon precursor for SnO2-C nano spheres. Consecutively, reduction process from SnO2 to Sn was conducted. The SnO2 redox process under hydrogen atmosphere has a significant problem. The reduction of SnO2 at 600 °C generates a liquid metallic tin, which aggregates into Sn particles. To prevent this problem, we employed a thick carbon layer coating to prevent the aggregation. Finally, phosphorization process was carried out using solvothermal method. Compared with other methods, the solvothermal route is convenient, simple, mild, and the morphology can also be controlled. With suitable temperature and time, Sn nano spheres were chemically transformed into Sn4P3 nano spheres, resulting in porous Sn4P3-C nano spheres. The synthesized porous Sn4P3-C nano sphere electrode exhibited an ultra-long cycle stability (about 2,000 cycles at 2,000 mAh/g) and high reversible capacity (700 mAh/g after 100 cycles at 200 mA/g) (Fig. 1). And its original morphology is apparently retained and the characteristic sphere geometry was unchanged after cycling test. We suggest the design strategy for the next-generation SIBs, and it can be applied to other phosphorus-metal alloying composites. Figure 1

Design and synthesis of amorphous SiOx structures generated by Sn quantum dots: growth mechanism and luminescent origin

SiOx structures with different diameters of a few hundreds of nanometers and/or a few micrometers are prepared using applied thermal evaporation. Subsequently, Sn quantum dot-based SiOx architectures are synthesized via the continuous steps of the carbothermal reduction of SnO2, substitution of Sn4+ for In3+, thermal oxidation of Si, Sn sublimation, interfacial reaction, and diffusion reaction consistent with corresponding phase equilibriums. Several crystalline and spherical-shaped Sn quantum dots with diameters between 2 and 7 nm are observed in the amorphous SiOx structures. The morphological evolution, including hollow Sn (or SnOx) sphere and wire-like, worm-like, tube-like, and flower-like SiOx, occurs stepwise on the Si substrate upon increasing the given process energies. The optical characteristics based on confocal measurements reveal the as-synthesized SiOx structures, irrespective of whether crystallinity is formed, which all have visible-range emissions originating from the numerous different-sized and -shaped Sn quantum dots permeating into the SiOx matrix. In addition, photoluminescence emissions ranging between ultraviolet and red regions are in agreement with confocal measurements. The origins of the morphology- and luminescence-controlled amorphous SiOx with Sn quantum dots are also discussed.