Sn Hydroxide Research Articles

Stable CO2 reduction under natural air on Ni–Sn hydroxide photocatalyst with dynamic renewable oxygen vacancies

Advanced photocatalysts are highly desired to activate the photocatalytic CO2 reduction reaction (CO2RR) with low concentration. Herein, the NiSn(OH)6 with rich surface lattice hydroxyls was synthesized to boost the activity directly under the natural air. Results showed that terminal Ni–OH could serve as donors to feed protons and generate oxygen vacancies (VO), thus beneficial to convert the activated CO2 (HCO3 −) mainly into CO (5.60 μmol g−1) in the atmosphere. It was flexible and widely applicable for a stable CO2RR from high pure to air level free of additionally adding H2O reactant, and higher than the traditional gas–liquid–solid (1.58 μmol g−1) and gas–solid (4.07 μmol g−1) reaction system both using high pure CO2 and plenty of H2O. The strong hydrophilia by the rich surface hydroxyls allowed robust H2O molecule adsorption and dissociation at VO sites to achieve the Ni–OH regeneration, leading to a stable CO yield (11.61 μmol g−1) with the enriched renewable VO regardless of the poor CO2 and H2O in air. This work opens up new possibilities for the practical application of natural photosynthesis.

Textural/structural evolution of cube/cauliflower-like MgSn(OH)6 nanophotocatalyst with excellent photocatalytic degradation of toxic dye pollutants

In this research, Mg–Sn hydroxide (MgSn(OH)6) nano semiconductor was synthesized using three different routes to investigate the texture/structure of MgSn(OH)6 on the photocatalytic properties of MgSn(OH)6 in RhB degradation. The nano semiconductors were characterized using XRD, FE-SEM, TEM, EDX, BET-BJH, DRS, PL, and the pHpzc. Morphological analyses for sono-hydrothermal sample showed 3D cubic microstructure. However, 3D cauliflower-like morphology was observed in the other samples. XRD analysis demonstrated the higher crystallinity of the sono-hydrothermal sample. BET-BJH analysis showed that the specific surface area and pore volume of this sample were 138.7 m2/g and 0.111 cm3/g, respectively. DRS analysis showed band-gap energy of about 4.1eV for all samples. Photocatalytic degradation experiments were conducted under UV-C light irradiation. The results demonstrated the advantage of the sono-hydrothermal sample owing to the cubic morphology, higher crystallinity and SBET, and lower recombination rate of the charge carriers. The photocatalytic degradation performance of the sample was evaluated in degradation of RhB, AO7, MO, and MB, which were 96, 93, 60, and 40%, respectively. The reusability study of sono-hydrothermal and hydrothermal samples was conducted in which the sono-hydrothermal sample showed higher efficiency and stability in four successive runs.

Effect of aluminum addition on the electrochemical corrosion behavior of Sn–3Ag–0.5Cu solder alloy in 3.5 wt% NaCl solution

The ternary eutectic Sn–Ag–Cu (SAC) solder alloys has become the most promising Pb-containing solders for the application in electronic packaging. The effect of Aluminum on the electrochemical corrosion behavior of Sn–3.0Ag–0.5Cu (SAC 305) solder alloy was investigated in 3.5 wt% NaCl solution in terms of potentiodynamic polarization and electrochemical impedance spectroscopy. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to characterize the samples after the electrochemical tests. Polarization studies indicated that an addition of 0.1 and 0.5 wt% Al in the Sn–3.0Ag–0.5Cu solder alloy shifted the corrosion potential (Ecorr) towards more negative values. The Impedance results revealed that the addition of Al with Sn–3.0Ag–0.5Cu solder alloy led to a lower corrosion resistance in terms of impedance values and the capacitance. The SEM images revealed existence of openings and pores in the corrosion product of solders containing Al. EDX and XRD analysis confirmed that the oxides and hydroxides of Sn and Al were the major corrosion products. AFM images exhibited that the surface becomes more rough and non-uniform with Al addition to SAC 305 solder alloy.

Electrochemically Assisted Deposition as a New Route to Transparent Conductive Indium Tin Oxide Films

Tin-doped indium oxide (ITO) films with Sn/In atomic ratios in the range 0−0.1 were synthesized by electrochemically assisted deposition (EAD). The process involves a fast one-step cathodic deposition of a highly crystalline In−Sn hydroxide (InSnOH) film followed by thermal conversion into ITO at 300 °C. The cathodic precipitation of InSnOH is preceded by formation of an In−Sn complex in solution. The films were characterized by field emission scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, UV−visible spectroscopy, and electrical measurements. In the Sn/In atomic ratio range 0−0.1, InSnOH and ITO films adopt the morphologies and cubic crystal structures of In(OH)3 and In2O3, respectively. The atomic environment of Sn and O atoms in the ITO films was shown to resemble that of films deposited by other techniques and commercial ITO samples made by chemical vapor deposition. Separate tin oxide/hydroxide phases were not observed by any of the characterization methods. The mor...

MINERALS OF AU, AG AND U IN VOLCANIC-ROCK-ASSOCIATED MASSIVE SULFIDE DEPOSITS OF THE NORTHERN APENNINE OPHIOLITE, ITALY

Ore samples from five copper sulfide deposits associated with Jurassic ophiolites in the Northern Apennine belt of Italy were found to contain gold, acanthite or argentite (Ag2S), and freibergite (Ag,Cu,Fe)12(Sb,As)4S13. These precious-metal minerals are part of a complex assemblage of microscopic to submicroscopic (^lt;10 mm) accessory phases, including uraninite, barite, galena, smithsonite, siderite, a La–Ce carbonate and a Sn hydroxide, attributable to the rare mineral hydroromarchite Sn3O2(OH)2. The textures of the sulfide host are indicative of metal deposition in a range of conditions, involving initial precipitation from hot, metal-charged solutions (syngenesis), followed by postdepositional replacement of biological material and resedimentation of clasts, at low temperature (epigenesis). Syngenetic gold is Ag-rich and associated with uraninite in Fe–Cu-rich ore. The fineness of native gold increases by loss of Ag into secondary Ag2S during seafloor weathering of the sulfides. Freibergite forms during recrystallization of sphalerite in massive Zn–Fe ore. Hydroromarchite occurs in massive Zn–Fe ore, closely related with late deposition of siderite and secondary pyrite, possibly due to the action of neutral to basic and reducing waters flushing through the ore in the initial stages of seafloor diagenesis. The widespread evidence for seafloor resedimentation and for biogenic- activity-driven reworking of the sulfides suggests a transition from proximal VMS to a more distal type of deposit formed by resedimentation processes in a dynamic tectonic environment. This scenario seems to be consistent with the interpretation of the Jurassic Ligurian ocean as a narrow basin in the early stage of its opening, having its modern analogue in the Red Sea.

Sn Stability of Sn-Modified Pt Electrode for Reduction of Nitrate

This work investigated the stability of a Sn-modified Pt electrode for the reduction of nitrate using two type electrodes prepared by adsorption or electrodeposition of Sn onto Pt. In order to find the causes for the instability of the electrode, the effects of the condition of the solutions in which the electrode was used and the potential applied to the electrode on the electrochemical and metallurgical behaviors of the Sn on the Pt electrode were investigated. The Sn of the Sn-modified Pt electrode existed as a Sn hydroxide form, which brought about an easy loss of the electroactivity of the electrode in solution. During the reduction of nitrate, the electroactivity of the electrode was affected by the potential applied to the electrode. When a more negative potential than the redox potential between and Sn was applied, the Sn hydroxide was converted to Sn metal that was diffused into Pt, which led to a loss of electroactivity of the electrode as well. The solid diffusion of Sn increased linearly with the applied potential. The Sn-electrodeposited Pt electrode was more favorable for maintaining the integrity of the electrode during the electrolysis than the Sn-adsorbed Pt electrode.

A Tungsten–Tin Mixed Hydroxide as an Efficient Heterogeneous Catalyst for Dehydration of Aldoximes to Nitriles

Mix and match: A tungsten–tin mixed hydroxide (W–Sn hydroxide), prepared by the simple coprecipitation method, acts as a reusable heterogeneous catalyst for the dehydration of various aldoximes to the corresponding nitriles (see scheme, top). Furthermore, the W–Sn hydroxide catalyst could be applied to the direct one-pot synthesis of nitriles from hydroxylamine and the corresponding aldehydes (see scheme, bottom).

Synthesis of tin-doped indium oxide nanoparticles by an ion-exchange and hydrothermal process

ITO nanopowder with uniform size was successfully prepared by an ion-exchange treatment followed by hydrothermal process. Ion-exchange treatment of the indium–tin chloride led to the formation of the homogeneous In–Sn hydroxide sol. Then, hydrothermal (240 °C for 7 h) followed by calcination (500 °C for 2 h) led to preparation of the cubic C-type rare-earth structured ITO nanopowders with a very narrow size distribution (97±5 nm). Using the regenerated resin to ion-exchange, the yield of ITO could be above 99%.

MINERALS OF Au, Ag AND U IN VOLCANIC-ROCK-ASSOCIATED MASSIVE SULFIDE DEPOSITS OF THE NORTHERN APENNINE OPHIOLITE, ITALY

Ore samples from five copper sulfide deposits associated with Jurassic ophiolites in the Northern Apennine belt of Italy were found to contain gold, acanthite or argentite (Ag2S), and freibergite (Ag,Cu,Fe)12(Sb,As)4S13. These precious-metal minerals are part of a complex assemblage of microscopic to submicroscopic (<10 μm) accessory phases, including uraninite, barite, galena, smithsonite, siderite, a La–Ce carbonate and a Sn hydroxide, attributable to the rare mineral hydroromarchite Sn3O2(OH)2. The textures of the sulfide host are indicative of metal deposition in a range of conditions, involving initial precipitation from hot, metal-charged solutions (syngenesis), followed by post-depositional replacement of biological material and resedimentation of clasts, at low temperature (epigenesis). Syngenetic gold is Ag-rich and associated with uraninite in Fe–Cu-rich ore. The fineness of native gold increases by loss of Ag into secondary Ag2S during seafloor weathering of the sulfides. Freibergite forms during recrystallization of sphalerite in massive Zn–Fe ore. Hydroromarchite occurs in massive Zn–Fe ore, closely related with late deposition of siderite and secondary pyrite, possibly due to the action of neutral to basic and reducing waters flushing through the ore in the initial stages of seafloor diagenesis. The widespread evidence for seafloor resedimentation and for biogenic-activity-driven reworking of the sulfides suggests a transition from proximal VMS to a more distal type of deposit formed by resedimentation processes in a dynamic tectonic environment. This scenario seems to be consistent with the interpretation of the Jurassic Ligurian ocean as a narrow basin in the early stage of its opening, having its modern analogue in the Red Sea.

Preparation and Characterization of Fine Indium Tin Oxide Powders by a Hydrothermal Treatment and Postannealing Method

Indium tin oxide powder with an In to Sn mole ratio of 95:5 was successfully prepared from a coprecipitated In–Sn hydroxide gel by hydrothermal processing followed by calcination at relatively low temperatures (∼500 °C). Hydrothermal treatment of the In–Sn coprecipitated gel at 300 °C for 24 h led to the formation of a single phase of tin-doped indium oxyhydroxide (InOOH:Sn). Under hydrothermal conditions the oxyhydroxide phase appeared well crystallized with particles ∼80 nm in size. Calcination of the oxyhydroxide phase above 450 °C in air yielded a substitutional-vacancy-type solid solution of In2Sn1−xO5−y.

Effectiveness of mossy tin filters to remove mercury from aqueous solution by Hg(II) reduction and Hg(0) amalgamation

Reduction of bivalent mercury (Hg(II)) by mossy tin combined with Hg(0) air stripping has been recently proposed as a method to remove Hg from groundwater. We investigated the effectiveness of mossy tin to remove Hg(II) from aqueous solution at different flow rates and determined the retention of Hg through the formation of HgSn amalgams. Results show that mossy tin layers of only 2 cm thickness can reduce 100% of 800 μg Hg(II) 1 −1 at a flow rate of about 1 volume of drainable porosity min −1 (Vol min −1), and even 100% of 5000 μg l −1 at 0.125 Vol min −1, 89% and 97% of the Hg(0) were retained in the filter through amalgamation. No Hg was remobilized from the loaded tin filters by chloride (10–50 mg Cl − l −1) or dissolved organic carbon DOC (0.5–6 mg DOC l −1). The capacity of mossy tin to adsorb Hg was found to be at least 5–6% of the weight of the filter. The study shows that mossy tin has a high capacity to remove Hg effectively from aqueous solution. Disadvantages arise from the release of tin from the filters exceeding legal limits of 20 μg l −1 in most cases but occurred as mostly insoluble tin particles or Sn hydroxide.

Surface characterization study of the chemical alteration of an air-exposed polycrystalline tin foil during H-atom exposures

An air-exposed polycrystalline Sn foil surface has been examined before and after exposure to H atoms using X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS). The foil initially contains large amounts of oxygen and carbon at the surface. C is present mostly as hydrocarbon contamination, and O is present as Sn hydroxide and surface water in addition to SnO, SnO 2 and transitional oxide (possibly Sn 3O 4), which has an O content between SnO and SnO 2. The C and O contents of the near-surface region are significantly reduced by exposure to the H-atom flux. The large hydroxyl group concentration is reduced through formation and desorption of water. A short 1-min exposure results in reduction of some of the SnO 2 or transitional oxide to SnO. Longer reduction periods result in the formation of a large amount of transitional oxide and some metallic Sn. ISS data indicate that the O and C contents of the outermost atomic layer initially increase upon exposure to H atoms due to a chemically induced driving force and then decrease. Migration of subsurface C and O becomes the rate-limiting step with regard to further removal of these species at room temperature.

電解鉄製造における不純物の共析挙動

Codeposition behaviors of Cu, Cd, Pb, Sn, Ni, Co, Zn and Mo with Fe have been studied in chloride and sulfate baths. The results obtained are as follows:(1) The single deposition of Fe proceeded with significant overvoltage, the degree of which depended on the type of electrolyte and temperature.(2) The codeposition of Cu and Cd with Fe was found to be regular type, resulting in higher contents of these impurities in the deposits than in the baths.(3) The codeposition behavior of Pb from chloride bath was similar to those of Cu and Cd. However, the content of the impurities in the deposits obtained from Pb-containing sulfate bath and Sn-containing chloride and sulfate baths was lowered by the precipitation of Pb sulfate and Sn hydroxide in the baths.(4) The contents of Ni and Co in the deposits showed lower value. This indicates the anomalous codeposition of Ni and Co with Fe, i. e., the preferential deposition of Fe over the wide range of electrolysis condition.(5) In the baths containing Zn2+, the anomalous codeposition in which less noble Zn deposits preferentially occurred. In this case, the codeposition of electrochemically less noble Zn should be considered to produce high purity Fe.(6) Mo content in the deposits decreases with an increase in current density to become less than 1% at higher current densities.

The anodic behaviour and Passivity of Tin in sulphate solutions

AbstractPassivation of spec‐pure Sn was studied in aerated, unstirred solutions of acid sulphate (H2SO4/Na2SO4) and neutral suphate (Na2SO4) using the potentiodynamic technique from an initial cathodic potential (−ve to open circuit potential) in the anodic direction and backwards to the initial potential. Only one anodic peak is observed in all results. The effect of etching is manifested in pure 0.1 M H2SO4 and in the solution containing 75% acid and 25% by vol 0.1 M Na2SO4. In all solutions, a grayish white film devlops on the Sn anode, and a white precipitate is formed in solution. Data are complied for the corrosion potential Ecor, the cathodic and anodic Tafel slopes, the corrosion cd Icor, the peak potential and the peak cd for acid sulphate solutions. The effect of scan rate has been demonstrated in 0.1 M Na2SO4 in the range 1‐100 m V/sec for unstirred and 1‐50 m V/sec for stirred solutions. The plot of peak cd Icc (Ip) vs the square root of the scan rate gives a striaght line with positive slope indicating diffusion kinetics for the anode film formation. USe of thermodynamic data leads to the possible formation of SnO, SnO2, Sn(OH)2 and Sn(OH)4 in the anode film. The limitations of the thermodynamic treatment is discussed. It is concluded that film formation is governed by a dissolution/precipitation mechanism based on diffusion kinetics. In the absence of the results of surface analysis, the anode film may be visualized to be composed of the oxides and hydroxides of Sn (thermodynamic evidence) together with sulphate anions (kinetic evidence). O2 evolution has not been detected up to 2.5 V (SCE), and this throws some light on the poor electron conductance of the anode film, and the probable dominance of lonic conductance during film growth.

Electrochemical Polarization and Passivation of Tin in neutral solutions of chloride, bromide and iodide ions

AbstractPassivation of commercial grade tin (99.5%) was studied in 0.1 M KCl, KBr and KI solutions using the potentiodynamic technique involving cathodic and anodic polarization at various scan rates. While low scan rates (0.1 mV/sec) lead to the complete deterioration of the anode in chloride solutions, higher scan rates of 1 and 5 mV/sec lead to the appearance of two anodic peaks. These peaks disappear at still higher rates (10 mV/sec). In bromide solutions, two anodic peaks appear with scan rates of 1 and 5 mV/sec, and only one peak is observed with 50 mV/sec. A white precipitate is formed in both chloride and bromide solutions during anodic scanning. No gas evolution (O2, Cl2 or Br2) could be detected up to anode potentials of 3–4 V (SCE). At scan rates of 1 mV/sec and higher values, pitting does not occur, and thick anode films are formed. The film is gray in chloride solutions, and yellowish gray in bromide solutions. Values of the corrosion potential Ecor are recorded for the forward and reverse scanning. The corrosion cd Icor is calculated both by the Tafel extrapolation procedure and by the linear polarization technique. The latter gives more accurate results. In Cl− and Br− solutions, the first anodic peak associated with passivation is more anodic than the equilibrium potentials for the tin/tin oxides or hydroxides. Passivation is explained as a result of the formation of the sparingly soluble salts Sn(OH)Cl, Sn(OH)Br which appear both in the precipitate and in the anode film. The passivating films are constituted at least partially of these basic salts, and contain a proportion of the oxides and hydroxides of Sn. From the effect of scan rates on the characteristics of the anodic peaks, it appears that the formation of thick anode films is governed by the diffusion kinetics for porous films. Of the three possibilities considered as explanations for the second anodic peak (oxidation of impurities, oxidation of halides to oxyacids, and structural changes in the film) the latter appears to be the most probable one.Thick anodic films are not formed in iodide solutions (scan rates 1, 5, 10 mV/sec), and the anode surface remains very bright. Dense evolution of I2 occurs during anodic polarization, and apart from I2 which dissolves in solution, the latter remains clear. Only one peak is observed in the forward anodic scanning. The polarization resistance technique gives Icor = 0. Thermodynamic calculations show that I3−, HIO, IO−, HIO3, IO3−, HIO4, and IO4− occur in 0.1 M KI solutions at potentials less anodic than the potential of the anodic peak (1.32 to 1.37 V, vs SCE). This peak potential is more anodic than the quilibrium potential for I2 evolution.