Regeneration behavior of tin oxide sorbent for warm syngas desulfurization

The steam regeneration and SO2 regeneration of tin oxide for warm syngas desulfurization is studied in the temperature range of 400-600 ℃. In the steam regeneration, reversible removal of H2S achieved. Regenerated H2S concentration increased with the increasing regeneration temperature. SnO2 sorbent can achieve a complete regeneration by steam at 500 and 600 ℃. In the 502 regeneration, elemental sulfur was produced by the reaction of SnS and SO2. Raising the regeneration temperature （500-600 ℃） or SO2 concentration （1.5-10 vol%） improved the regeneration rate. Under SO2 regeneration at 500 ℃, SnS2 formed in the sorbent due to the interconversion of tin sulfides. Under steam regeneration or SO2 regeneration, the cyclic breakthrough sulfur capacity of SnO2 sorbent decreased because of the sintering caused by low melting component SnS. A two-stage regeneration process was applied to recover the elemental sulfur which achieved a complete regeneration.

Confining SnS_(2)@N,S codoped carbon in core-shell beads of necklace-like fibers towards ultrastable anode for flexible potassium-ion battery

Tin sulfide(SnS_(2))with high theoretical capacity and layered structure is a promising anode candidate for potassium-ion batteries(PIBs).However,the sluggish kinetics,huge volume expansion and polysulfide intermediates dissolution restrict its development.To address these issues,a necklace-like hybrid fiber with core–shell beads is designed to achieve the high-performance anode for PIBs.The cores of the beads are assembly by SnS_(2)nanocrystals dotted in N,S codoped carbon(NSC)matrix.Then they are encapsulated by NSC based shell and form the core–shell structured beads internal the hybrid fiber(CSN fiber).The carbon matrix of SnS_(2)@NSC CSN fiber gives fast ion/electron pathways and facilitates to decrease particle aggregation.Meanwhile,N,S codpants favor to trap the polysulfides intermediates and alleviate the sulfur loss during cycling.Moreover,the voids internal the beads further provide the high accommodation to volume change.Taken all above advantages,the SnS_(2)@NSC CSN fiber achieves the excellent high rate capability and ultrastable cycling property,which obtains a low capacity decay rate of 0.013%after 2000 cycles at 2 A g^(-1).Moreover,its good mechanical characteristics ensure the fabrication of the flexible PIB full cell,which achieves the high pliability,superior power/energy density and high reliability in diverse working conditions.Therefore,this work not only gives a new clue to design the highperformance electrode for potassium storage,but also propels the applications of PIBs for diverse electronics.

Influence of In-doping on resistivity of chemical bath deposited SnS films

SnS and SnS：In films were deposited onto glass substrates by chemical bath technique. The structure and surface morphology of the SnS：In films were studied by X-ray diffraction （XRD） and scanning electron microscope （SEM） respectively. Energy dispersive spectroscopy （EDS） showed the existence of In in the films. The undoped SnS film exhibited a rather high resistivity and InCl3 could reduce the resistivity of these films by two orders approximately. The band gaps of the SnS and SnS：In films were evaluated from the optical transmission spectra.

Influence of growth conditions on the electrochemical synthesis of SnS thin films and their optical properties

Tin sulfide （SnS） thin films were prepared by electrodeposition onto fluorine-doped tin oxide （FTO） glass substrates using an aqueous solution containing SnCl2 and Na2S2O3 at various deposition potentials （L） and bath concentrations. The pH value and temperature of the solution were kept constant. The deposited films were characterized using X-ray diffraction （XRD）, field-emission scanning electron microscopy （FESEM）, photoluminescence （PL）, and ultraviolet-visible （UV-Vis） spectroscopy. The FESEM images demonstrated that changes in the deposition potential （E） and solution concentration led to marked changes in the morphology of the deposited SnS films. Energy-dispersive X-ray analysis （EDXA） results showed that the SrdS atomic ratio strongly depended on both the solution concentration and the deposition potential. To obtain an SrdS atomic ratio approximately equal to l, the optimal Sn2＋/S2O2- 3 molar ratio and E parameter were 1/8 and -1.0 V, respectively. The XRD patterns showed that the synthesized SnS was obviously polycrystalline, with an orthorhombic structure. The effects of the variations of bath concentration and deposition potential on the band-gap energy （Eg） were studied using PL and UV-Vis experiments. The PL spectra of all the SnS films contained two peaks in the visible region and one peak in the infrared （IR） region. The UV-Vis spectra showed that the optical band-gap energy varies from 1.21 to 1.44 eV.

Predicting 2D silicon allotropes on SnS2

A first principles study on the stability and structural and electronic properties of two-dimensional silicon allotropes on a semiconducfing layered metal-chalcogenide compound, namely SnS2, is performed. The interactions between the two- dimensional silicon layer, commonly known as silicene, and the layered SnS2 template are investigated by analyzing different configurations of silicene. The calculated thermodynamic phase diagram suggests that the most stable configuration of silicene on SnS2 belongs to a family of structures with Si atoms placed on three different planes; so-called dumbbell silicene. This particular dumbbell silicene structure preserves its atomic configuration on SnS2 even at a temperature of 500 K or as a ＂flake＂ layer （i.e., a silicene cluster terminated by H atoms）, thanks to the weak interactions between the silicene and the SnS2 layers. Remarkably, an electric field can be used to tune the band gap of the silicene layer on SnS2, eventually changing its electronic behavior from semiconducting to （semi）metallic. The stability of silicene on SnS2 is very promising for the integration of silicene onto semiconducting or insulating substrates. The tunable electronic behavior of the silicene/SnS2 van der Walls heterostructure is very important not only for its use in future nanoelectronic devices, but also as a successful approach to engineering the bang-gap of layered SnS2 paving the way for the use of this layered compound in energy harvesting applications.

Flexible SnS nanobelts： Facile synthesis, formation mechanism and application in Li-ion batteries

[020]-oriented tin sulfide nanobelts with a length/thickness ratio of 100 have been synthesized by a facile hydrothermal method without any surfactants, and the nanobelts have shown good strain-accommodating properties as well as good electrochemical performance as the anode for Li-ion batteries. The formation of the nanobelts results from a precipitation-dissolution-transformation mechanism, and the [020] oriented growth can be ascribed to the {010} facet family having the lowest atomic density. In particular, SnS shows clear Li-Sn alloying/de-alloying reversible reactions in the potential range 0.1-1.0 V. Based on galvanostatic measurements and electrochemical impedance spectroscopy, SnS nanobelts have shown impressive rate performance. The post-cycled SnS nanobelts were completely transformed into metallic tin, and preserved the one-dimensional structure due to their flexibility which accommodates the large volumetric expansion.

Aerosol-assisted rapid synthesis of SnS-C composite microspheres as anode material for Na-ion batteries

SnS-C composite powders were prepared through one-pot spray pyrolysis for use as anode materials for Na-ion batteries. C microspheres with uniformly attached cubic-like SnS nanocrystals, which have an amorphous C coating layer, were formed at a preparation temperature of 900 ℃. The initial discharge capacities of the bare SnS and SnS-C composite powders at a current density of 500 mA·g^-1 were 695 and 740 mA·h·g^-1, respectively. The discharge capacities after 50 cycles and the capacity retentions measured from the second cycle of the bare SnS and SnS-C composite powders were 25 and 433 mA.h.g-1 and 5 and 89%, respectively. The prepared SnS-C composite powders with high reversible capacities and good cycle performance can be used as Na-ion battery anode materials.

High thermoelectric figure of merit ZT>1 in SnS polycrystals

Eco-friendly tin sulfide(SnS)has attracted increasing attention in the thermoelectric community because of its elemental abundance and analogous crystal structure to SnSe as a new thermoelectric material.However,so far no high dimensionless thermoelectric figure of merit ZT>1 was reported in SnS polycrystals.This work found an effective strategy for enhancing the thermoelectric performance of ptype polycrystalline SnS by Ag doping and vacancy engineering,leading to three orders of magnitude increase in carrier concentration and optimized effective mass and carrier mobility.As a result of the enhanced electrical conductivity,three times higher power factor ~3.85 μW/cm K^(2) at 877 K is realized in Sn_(0.995)Ag_(0.005)S sample.Interestingly,nanostructuring with Ag nano-precipitates were formed in the Agdoped SnS sample.Moreover,with introducing Sn vacancies in the crystal structure of Sn_(0.995-vac)Ag_(0.005)S,the power factor further enhanced to~4.25 μW/cm K^(2).In addition to the low-frequency phonons scattering by Ag nano-precipitates,dislocations strengthens the scattering of mid-frequency phonon,leading to an ultralow lattice thermal conductivity <0.5 W/m K above 800 K and a record high ZT up to 1.1 at 877 K in Sn_(0.99)Ag_(0.005)S polycrystals.

Effect of SnCl2 and SnCl4 precursors on SnSx thin films prepared by ultrasonic spray pyrolysis

Thin films of SnSx,semiconductors,have been successfully synthesized by ultrasonic spray pyrolysis technique,using two precursors namely：tin（II）chloride and tin（IV）chloride,respectively.The solutions were prepared by the dilution of different Sn molarities of the two precursors separately.The precursor molarities were varied from 0.04 to 0.07 mol/L,whereas that of S was fixed at 0.1 mol/L.The present work focuses on the effect of the different precursor’s molarities on the nature and the properties of the prepared thin films in order to optimize the growth conditions.X-ray diffraction analysis reveals that the precursor’s molarities alter the grain size of the prepared films,which varied from 8 to 14 nm and from 12 to 16 nm,according to the used precursor.The films analysis by SEM,shows that the SnS2 films are more dense and smooth than the SnS films.The composition of the elements is analysed with an EDX spectrometer,and the obtained result for M（sn）=0：07 mol/L indicates that the atomic ratio of Sn to S is 51.57：48：43 and 36：64 for films synthesized from the first and second precursors respectively.Electrical measurements show that the conductivity behavior depends on the used precursors and their molarities.

Low carrier concentration leads to high in-plane thermoelectric performance in n-type SnS crystals

As a simple binary compound, p-type SnS shows great competitiveness in thermoelectrics due to the certain appealing carrier and phonon transport behaviors, coupled with its cost-effectiveness, earth-abundance and environmental compatibility. To promote the application of low-cost thermoelectric devices, we synthesized n-type SnS crystals through bromine doping. Herein, we report a high in-plane power factor of ~28 μW cm^(-1)K^(-2), and attribute it to an outstanding in-plane carrier mobility in the crystal form and the large Seebeck coefficient benefitting from the low carrier concentration. The calculations of elastic properties show that the low lattice thermal conductivity in SnS is closely related to its strong anharmonicity. Combining the excellent electrical transport properties with low thermal conductivity, a final ZT of ~0.4 is attained at 300 K, projecting a conversion efficiency of ~5% at 873 K along the in-plane direction.

Effect of deposition conditions on the physical properties of Sn_xS_y thin films prepared by the spray pyrolysis technique

Tin sulfide thin films （Snx Sy） with an atomic ratio of y/x = 0.5 have been deposited on a glass substrate by spray pyrolysis. The effects of deposition parameters, such as spray solution rate （R）, substrate temperature （Ts） and film thickness （t）, on the structural, optical, thermo-electrical and photoconductivity related properties of the films have been studied. The precursor solution was prepared by dissolving tin chloride （SnC14, 5H2O） and thiourea in propanol, and SnxSy thin film was prepared with a mole ratio of y/x = 0.5. The prepared films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and UV-vis spectroscopy. It is indicated that the XRD patterns of SnxSy films have amorphous and polycrystalline structures and the size of the grains has been changed from 7 to 16 nm. The optical gap of SnxSy thin films is determined to be about 2.41 to 3.08 eV by a plot of the variation of （αhv）2 versus h v related to the change of deposition conditions. The thermoelectric and photo-conductivity measurement results for the films show that these properties are depend considerably on the deposition parameters.

Structural, optical and electrical properties of Sn_xS_y thin films grown by spray ultrasonic

Tin sulfide（Snx Sy/ thin films were prepared by a spray ultrasonic technique on glass substrate at 300℃.The influence of deposition time tD2, 4, 6, 8 and 10 min on different properties of thin films, such as（XRD）,photoluminescence（PL） and（UV） spectroscopy visible spectrum and four-point were investigated. X-ray diffraction showed that thin films crystallized in SnS2, SnS, and Sn2S3 phases, but the most prominent one is SnS_2. The results of the（UV） spectroscopy visible spectrum show that the film which was deposited at 4 min has a large transmittance of 60% in the visible region. The photoluminescence spectra exhibited the luminescent peaks in the visible region, which shows its potential application in photovoltaic devices. The electrical resistivity（ρ） values of SnxSy films have changed from 8.1×1064to 1.62Ω·cm with deposition time.

A novel method of water remediation of organic pollutants and industrial wastes by solution- route processed CZTS nanocrystals

CZTS(Cu_(2)ZnSnS_(4)),a P-type semiconductor with a direct bandgap(1.2-1.7eV),earth-abundant,non-toxic,and has a large absorption coefficient makes it extremely useful in optoelectronics and light-harvesting applications.In this work,CZTS is prepared by an ingenious,cost-effective colloidal route using the‘hotinjection’method with the usage of different ligands.The XRD and Raman spectroscopy shows the single-phase highly crystalline CZTS nanoparticles with kesterite structure.The TEM results show that the size of CZTS nanoparticles is about 2-5 nm and monodispersity is confirmed by DLS(Dynamic Light Scattering).FTIR confirms the presence of different ligands used in CZTS preparation.The Uv-vis absorption shows the direct bandgap of 1.5-1.7eV.The contact angle study shows the hydrophobic nature of as-synthesized CZTS nanoparticles which were further ligand exchanged with L-cysteine hydrochloride to make it hydrophilic to study the photocatalytic degradation activity of organic pollutants and industrial waste in the water.The photocatalysis experiments were performed under two conditions:(i)under bare sunlight(Intensity~900 W/m^(2))(ii)focussing the sample under the sunlight via converging lens(1800 W/m^(2)).The photocatalytic efficiencies were then compared and the best photocatalytic efficiency achieved under sunlight was 98.4%for organic pollutants and 75%for industrial waste via converging lens while the corresponding efficiencies with bare sunlight were 98.1% and 73% respectively.To the best of the author’s knowledge,a rapid and highly efficient photocatalysis of CZTS NPs employing a converging lens for water-remediation without the usage of noble&transition-metals has been reported for the first time.

Hydrazine processed Cu2SnS3 thin film and their application for photovoltaic devices

Copper tin sulfide （Cu2SnS3） was a potential earth abundant absorber material for photovoltaic device application. In this contribution, triclinic Cu2SnS3 film with phase pure composition and large grain size was fabricated from a hydrazine solution process using Cu, Sn and S as the precursors. Absorption measurement revealed this Cu2SnS3 film had a direct optical band gap of 0.88 eV, and Hall effect measurement indicated the film was p-type with hole mobility of 0.86 cmE/Vs. Finally Mo/Cu2SnS3/ CdS/ZnO/AZO/Au was produced and the best device efficiency achieved was 0.78%. Also, this device showed improved device performance during ambient storage. This study laid some foundation for the further improve- ment of Cu2SnS3 solar cell.