Commercial SnO2 Nanoparticles Research Articles

Tailoring the alkalinity of SnO2 colloidal suspension for high‐performance and stable perovskite solar cells

The commercial tin oxide (SnO2) colloidal suspension is widely utilized as an electron transport layer (ETL) in high‐performance perovskite solar cells (PSCs) due to its favorable material properties and potential for large‐scale production. However, despite significant efforts have been proposed to address bulk transport and interface recombination issues through the introduction of additives or modifiers, the efficiency of PSCs based on commercial SnO2 nanoparticles remains limited to around 25%. In this study, we highlight the crucial role of the physicochemical characteristics of the SnO2 colloidal suspension in shaping the morphology, electrical properties and optical properties of the SnO2 ETL. By controlling the pH value of the SnO2 solution with weak acids such as carbonic acid, we successfully induced the reassembly of metal oxide nanoparticles into smaller sizes with more homogeneous dispersion and dense interconnections. Consequently, the resulting SnO2 ETL exhibited enhanced crystallinity, high conductivity, low surface defects, and high optical transmittance. As a result, we achieved a significant improvement in the power conversion efficiency of the target PSCs, increasing it from 23.10% to 24.70%. This improvement was attributed to higher voltage, photocurrent, and fill factor compared to the relevant control samples. We observed a similar device improvement using phosphoric acid, indicating that our approach represents a universal technique to further enhance the quality of SnO2 ETL for large‐area, high‐efficiency, and stable PSCs.This article is protected by copyright. All rights reserved.

Controlled Preparation of Cross-Linked SnO2 Hollow Nanotube Networks for Electrocatalytic CO2 Reduction

The electrochemical system based on water, CO2, and electricity is the key technology to realize the coexistence and combination of renewable energy and fossil energy, which can convert CO2 molecules into high-value-added products under mild and controlled conditions, thus achieving carbon neutrality. Designing efficient electrocatalysts to realize highly active, selective, and stable CO2RR has become one of the vital issues. Particularly, the nanostructure design and interface adjustment of electrocatalysts have been regarded as the key points for improving their catalytic performance. Herein, a tin dioxide hollow nanotube (SnO2 HNT) catalyst with a three-dimensional cross-linked network structure has been fabricated by electrospinning and rapid-heating calcination. The morphology and component structure of SnO2 HNTs were analyzed by a series of characterizations. The performance in electrocatalytic carbon dioxide reduction reaction (eCO2RR) was further tested. Owing to the hollow nanostructure, the catalyst possessed a large specific surface area and abundant active sites, which greatly accelerated mass transport and electron mobility. During eCO2RR, SnO2 HNTs achieved a peak faraday efficiency value of 87.4% for C1 products at −1.1 V vs RHE, which significantly suppressed the occurrence of hydrogen evolution side reactions. In addition, compared with the commercial SnO2 nanoparticles or partially reduced Sn/SnO2, the catalytic activity and selectivity of CO2-to-formate conversion significantly increased under the same potential, indicating that the optimization of electronic/geometric structure for high-yield metal oxides can effectively improve the comprehensive performance of eCO2RR.

Synergistic Engineering of Conduction Band, Conductivity, and Interface of Bilayered Electron Transport Layers with Scalable TiO2 and SnO2 Nanoparticles for High-Efficiency Stable Perovskite Solar Cells

A simple, synergistic engineering of the conduction band (CB), conductivity, and interface of TiO2-based bilayered electron transport layers (ETLs) via scalable TiO2 and SnO2 nanoparticles processed at low temperature (≤ 100 °C) for regular planar perovskite solar cells (PSCs) was developed. The bottom layer (Lt-TiO2:SnO2 nanocomposite film) was prepared by spin coating from the ethanol suspension of small ground TiO2 nanoparticles with big ground SnO2 nanoparticles as the additive. The top C-SnO2 layer (spin-coated from the concentrated commercial SnO2 nanoparticles (C-SnO2 NPs, 20 wt %, 7 nm in size suspended in H2O)) can be regarded as an interlayer between Lt-TiO2:SnO2 and perovskite (Psk) absorbers. Bilayered Lt-TiO2:SnO2/C-SnO2 ETLs are dense films with a cascade CB, good conductivity, facile electron extraction/transport ability, and a highly hydrophilic surface for depositing high-quality Psk films. Regular planar PSCs based on Lt-TiO2:SnO2/C-SnO2 ETLs combined with a (FAI)0.90(PbI2)0.94(MABr)0.10(PbBr2)0.10 absorber and a spiro-OMeTAD hole transporter achieved the highest power conversion efficiency of 22.04% with a negligible current hysteresis. The champion cell lost less than 3% of the initial efficiency under continuous room lighting (1000 lux) for 1000 h (lost 10% after 2184 h) without encapsulation under an inert atmosphere. Four related low-temperature-processed ETLs (Lt-TiO2/C-SnO2, Lt-C-SnO2, Lt-TiO2:SnO2, and Lt-TiO2) were fabricated using the same metal oxide nanoparticle suspensions and studied simultaneously to reveal the function of each metal oxide in the bilayered Lt-TiO2:SnO2/C-SnO2 ETLs. In the bottom Lt-TiO2:SnO2 layer, small TiO2 nanoparticles were needed for making a dense film, and highly conducting big SnO2 nanoparticles are used to increase the conductivity of ETLs and a handy electron transport path for reducing the charge accumulation and series resistance of the cell. A top C-SnO2 layer (regarded as an interlayer between Psk and Lt-TiO2:SnO2) was used to extract/transport electrons facilely, to form a bilayered ETL with a cascade CB, and to create a hydrophilic surface to deposit high-quality Psk films to enhance the photovoltaic performance of the PSCs. This study provides a blueprint for designing good-performance ETLs for high-efficiency, stable regular planar PSCs using various sized nanoparticles prepared in a very simple and low-cost way.

High performance SnO2 pure photoelectrode in dye-sensitized solar cells achieved via electrophoretic technique

This work shows a simple method utilizing electrophoretic deposition (EPD) of commercial SnO2 nanoparticles films on fluoride-doped tin oxide (FTO) substrate. In this process at constant voltage, depositions cycles are well controlled to achieve SnO2 films with different grain and pore sizes. The experimental results indicate that the method utilizing electrophoretic deposition to SnO2 films plays an important role with photoelectrode in DSSCs compared others methods of deposition because do not presence surfactantes and other contaminants waste. In addition, it was found that reduced film porosity can concentrate dye molecules and be responsible for reducing the electron supply. Effects of the bulk traps and surface states within the SnO2 films on the recombination of the photo-injected electrons strongly depend on the SnO2 film compression. The best device (with a average grain size of 156.0 nm and with an average pore size of 468.0 nm) gives a conversion efficiency of 3.89%, having a short circuit current density exclusive of 14.27 mA/cm2 to incident light of 100 mW/cm2.

Room-temperature synthesis of tin oxide nanoparticles using gallic acid monohydrate for symmetrical supercapacitor application

Tin oxide (SnO2) nanoparticles were synthesized using gallic acid monohydrate as a reducing agent via precipitation method at room temperature. The synthesized SnO2 nanoparticles (S-SnO2NPs) were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Energy dispersive x-ray (EDX) and Field emission gun scanning electron microscope (FEG-SEM). The results showed the formation of a tetragonal rutile crystal of spherical shape SnO2 nanoparticles with an average size of 20.40 nm. XPS analysis confirmed the oxidation state of Sn4+ with an energy gap of 8.5 eV. The electrochemical properties of S-SnO2NPs were coated on the electrochemically treated carbon cloth (S-SnO2NPs@ETCC) electrode were compared with the commercial SnO2 nanoparticles (C-SnO2NPs@ETCC) electrode. The electrochemical measurement displayed maximum specific capacitance of 523 F/g and 482 F/g for S-SnO2NPs@ETCC and C-SnO2NPs@ETCC electrodes at a scan rate of 5 mV/s in 1 M H2SO4 electrolyte, respectively. Further, the assembled symmetrical supercapacitor (SS) exhibited a specific capacitance of 156 F/g at a scan rate of 5 mV/s and a capacitance retention rate of 94.7% after 5000 cycles at a current density of 20 A/g for total mass loading of 10 mg cm−2 in hydrogel polymer electrolyte (PVA-H2SO4).

Preparation and enhanced photocatalytic activity of Co/F codoped tin oxide nanotubes/nanowires: a wall thickness-dependence study

Aligned Co/F codoped tin oxide (SnO2) nanotubes/nanowires with high photocatalytic activity were successfully prepared via the liquid-phase deposition (LPD) process by immersing the anodic aluminum oxide template in a (NH4)2SnF6 aqueous solution. The mechanism proposed for the formation of Co/F codoped SnO2 nanotubes/nanowires was discussed. The results showed that the morphology can be controlled by the careful manipulation of process parameters. The Co/F codoped SnO2 first nucleated on the alumina membrane walls and then grew inwards, filling the nanoholes until nanotubes were obtained. By prolonging the deposition period up to 240 min, nanowires were also obtained. The photocatalytic behavior of the products was evaluated based on the photodegradation of methylene blue (MB) as a model organic compound under visible-light irradiation. The Co/F codoped SnO2 nanotubes fabricated at 25 °C for 240 min exhibited the highest photocatalytic activity. In addition, the degradation of MB with the Co/F codoped SnO2 nanotubes/nanowires confirmed improved photocatalytic performance compared to that of commercial SnO2 nanoparticles and SnO2 nanotubes.

Solubility-dependent gelatination toward N-doped SnOx/C deriving from commercial SnO2 for the ultrastable lithium storage

More than 200% volume change is the major restriction for the practical application of Sn-based anode materials in lithium-ion batteries. In order to prepare carbon-coated structure by a facile, low-cost, facile and common method, the solubility-dependent gelatination of carboxylated chitosan is developed for the precursors of N-doped SnOx/C composites with commercial SnO2 nanoparticles as Sn source. The phase, porosity and ratio of Sn/C of the composites can be easily controlled by changing the raw materials ratio and calcination temperature. According to the results, N-doped SnOx/C anode material shows excellent stability (93.9% retention of the second cycle) and superior specific capacity (679.8 and 542.3 mAh g−1 after 300 cycles at 200 mA g−1 and 1000 mA g−1, respectively). This strategy lights on the illuminating design of 3D carbon-coated Sn-based anode by liquid carbon source and commercial solid tin source, which can improve electrochemical performance for next-generation lithium-ion batteries.

Cellulose-derived tin-oxide-nanoparticle-embedded carbon fibers as binder-free flexible Li-ion battery anodes

Cellulose has attracted attention as a biomass carbon precursor owing to its abundant reserves and unique properties such as a hierarchical fibrous structure and good mechanical properties. Here, we fabricate cellulose-derived carbon fibers via a facile electrospinning and carbonization process by using cellulose acetate precursor. The prepared carbon fibers are directly used as binder-free flexible anodes for Li ion batteries. They exhibit a high initial reversible specific capacity of 555 mA h g−1 with better cycling stability than carbonized commercial cellulose electrodes. To design extensive lithium storage electrodes, cellulose-derived carbon fiber/SnO2 composites are fabricated through electrospinning. In order to prevent the degradation of the active material, we encapsulate SnO2 nanoparticles in cellulose-derived carbon fibers with a large amount of SnO2 (46.4 wt%), which is evenly dispersed in the fibrous carbon matrix. Cellulose-derived carbon fiber/SnO2 electrodes reveal a high reversible capacity of 667 mA h g−1 and stable cycling retention of 76% over 100 cycles at 200 mA g−1, which signify much better cycling performance than commercial SnO2 nanoparticles. These properties are reflected in the advantages of cellulose-derived carbon fiber/SnO2 composite electrodes such as high reactivity, good mechanical properties, and high electrical conductivity that originate from the cellulose-based fibril nanostructure.

Molten salt synthesis of oxygen-deficient SnO2 crystals with enhanced electrical conductivity

Spiky polycrystalline SnO2 balls assembled from pyramid-shaped SnO2 nanocrystals with surface oxygen vacancies were synthesized by a simple and facile in-situ molten salt oxidation method using SnCl2 as the tin source and graphite as the surface reductant. In this method, perfect SnO2 nanocrystals are first formed on the surface of graphite particles at 500 °C. By increasing the processing temperature to 700 °C, the formation of surface oxygen vacancy defects was confirmed, supported by various characterisation methods including Raman and XPS spectroscopy. A sharp increase in the bulk electrical conductivity of the samples was detected by exceeding the onset temperature corresponding to the formation of oxygen deficient SnO2 crystals, at which the conductivity of the sample significantly outperformed that of commercial SnO2 nanoparticles. The formation of oxygen vacancies on SnO2 crystals is thermodynamically studied, and suggested to occur by surface carbon reduction of the crystals at sufficiently high temperatures. The enhanced electrical conductivity of oxygen deficient SnO2 crystals can lead to a wider application of tin oxides in advanced electrical applications.

Rapid and scalable synthesis of crystalline tin oxide nanoparticles with superior photovoltaic properties by flame oxidation

Abstract

Hydrothermally hollow SnO 2 microspheres as sodium ion battery anode with high capacity and superior stability

Hollow SnO2 microspheres were synthesised through a hydrothermal process with post-calcination in air. Compared with commercial SnO2 nanoparticles, this organised and hollow SnO2 microspheres show a 3.3–3.6 times higher charge/discharge capacity, a superior cycling stability and a higher Coulomb efficiency when used as an anode material for sodium ion batteries (SIBs). The superior performance of hollow SnO2 microspheres was mainly attributed to the hollow structure with number of smaller nanoparticles. Compared with the disordered commercial SnO2 nanoparticles, the organised and hollow SnO2 microspheres with mesopores and micropores not only can facilitate charge transfer between the electrode and electrolyte, improve electronic and ionic transports, but also can accommodate the volume change to enhance the cycling stability of SnO2-based SIB anodes. This work also demonstrates that the unique hollow structures can be broadly used to construct electrode nanomaterials.

Reduced SnO2 Porous Nanowires with a High Density of Grain Boundaries as Catalysts for Efficient Electrochemical CO2 -into-HCOOH Conversion.

Electrochemical conversion of CO2 into energy-dense liquids, such as formic acid, is desirable as a hydrogen carrier and a chemical feedstock. SnOx is one of the few catalysts that reduce CO2 into formic acid with high selectivity but at high overpotential and low current density. We show that an electrochemically reduced SnO2 porous nanowire catalyst (Sn-pNWs) with a high density of grain boundaries (GBs) exhibits an energy conversion efficiency of CO2 -into-HCOOH higher than analogous catalysts. HCOOH formation begins at lower overpotential (350 mV) and reaches a steady Faradaic efficiency of ca. 80 % at only -0.8 V vs. RHE. A comparison with commercial SnO2 nanoparticles confirms that the improved CO2 reduction performance of Sn-pNWs is due to the density of GBs within the porous structure, which introduce new catalytically active sites. Produced with a scalable plasma synthesis technology, the catalysts have potential for application in the CO2 conversion industry.

Reduced SnO2 Porous Nanowires with a High Density of Grain Boundaries as Catalysts for Efficient Electrochemical CO2‐into‐HCOOH Conversion

AbstractElectrochemical conversion of CO2 into energy‐dense liquids, such as formic acid, is desirable as a hydrogen carrier and a chemical feedstock. SnOx is one of the few catalysts that reduce CO2 into formic acid with high selectivity but at high overpotential and low current density. We show that an electrochemically reduced SnO2 porous nanowire catalyst (Sn‐pNWs) with a high density of grain boundaries (GBs) exhibits an energy conversion efficiency of CO2‐into‐HCOOH higher than analogous catalysts. HCOOH formation begins at lower overpotential (350 mV) and reaches a steady Faradaic efficiency of ca. 80 % at only −0.8 V vs. RHE. A comparison with commercial SnO2 nanoparticles confirms that the improved CO2 reduction performance of Sn‐pNWs is due to the density of GBs within the porous structure, which introduce new catalytically active sites. Produced with a scalable plasma synthesis technology, the catalysts have potential for application in the CO2 conversion industry.

Nanowire-based zinc-doped tin oxide microtubes for enhanced solar energy utilization efficiency

Nanowire-based Zn-doped SnO2 microtubes are synthesized via a solvothermal route for solar energy utilization. The unique architecture exhibits a hierarchical structure: the interconnected nanowires vertically stand on the surface of tube with several micrometers in length. With this structure as photoanodes for the dye-sensitized solar cells (DSSCs), an overall 4.22% photoconversion efficiency is obtained, which is nearly thrice as high as that of the DSSCs constructed using a photoanode of commercial SnO2 nanoparticles. Moreover, with the Zn-doped SnO2 as the photocatalyst, it exhibits both higher photocatalytic activity and better recyclability for the degradation of dyes. These improvements are ascribed to fast electron transport, high surface area, and promoted charge separation made possible by the fancy structure of Zn doping into the SnO2 framework.

Novel Carbon-Encapsulated Porous SnO2 Anode for Lithium-Ion Batteries with Much Improved Cyclic Stability.

Porous SnO2 submicrocubes (SMCs) are synthesized by annealing and HNO3 etching of CoSn(OH)6 SMCs. Bare SnO2 SMCs, as well as bare commercial SnO2 nanoparticles (NPs), show very high initial discharge capacity when used as anode material for lithium-ion batteries. However, during the following cycles most of the Li ions previously inserted cannot be extracted, resulting in considerable irreversibility. Porous SnO2 cubes have been proven to possess better electrochemical performance than the dense nanoparticles. After being encapsulated by carbon shell, the obtained yolk-shell SnO2 SMCs@C exhibits significantly enhanced reversibility for lithium-ions storage. The reversibility of the conversion between SnO2 and Sn, which is largely responsible for the enhanced capacity, has been discussed. The porous SnO2 SMCs@C shows much increased capacity and cycling stability, demonstrating that the porous SnO2 core is essential for better lithium-ion storage performance. The strategy introduced in this paper can be used as a versatile way to fabrication of various metal-oxide-based composites.

Template-free synthesis of flower-like SnO2 hierarchical nanostructures with improved gas sensing performance

In the work, flower-like SnO2 hierarchical nanostructures assembled with numerous nanosheets were successfully prepared through a facile template-free hydrothermal route using SnSO4 as the tin source and water as the solvent. The process was simple, green, and effective. The obtained SnO2 products had uniform flower-like morphology, hierarchical nanostructures, and high specific surface area of 136.0m2/g. The investigation of the experimental parameters demonstrated that the tetrapropylammonium hydroxide (TPAOH) played a crucial role in determining the structure and properties of the final products, which was acted as both the alkali source and morphology director. Ag/SnO2 nanostructures were also fabricated by a conventionally impregnation method, in which Ag nanoparticles with the size of 20–30nm were uniformly grown into the surface of SnO2 product. The gas sensing tests indicated that both SnO2 and Ag/SnO2 sensors exhibited better gas sensing properties to n-butanol at low working temperature of 160°C compared with the sensor based on the commercial SnO2 nanoparticles. As expected, the sensor based on the Ag/SnO2 product showed obviously enhancement in gas sensing performance. The growth process and gas-sensing mechanism were investigated based on the experimental results. The present protocol may be extended to the synthesis of other metal oxides with different nanostructures for more potential applications.

Ar/O2 and H2O plasma surface modification of SnO2 nanomaterials to increase surface oxidation

Tin oxide operates widely as a gas sensor for a variety of molecules via a mechanism that relies on interactions with adsorbed oxygen. To enhance these interactions by increasing surface oxygen vacancies, commercial SnO2 nanoparticles and CVD-grown SnO2 nanowires were plasma modified by Ar/O2 and H2O plasmas. Scanning electron microscopy revealed changes in nanomaterial morphology between pre- and post-plasma treatment of H2O treated materials but not Ar/O2 treated materials. Powder X-ray diffraction patterns of the bulk SnO2 showed the Sn4+ is reduced by H2O and not Ar/O2 plasma treatments. X-ray photoelectron spectroscopy indicated Ar/O2 treatment results in increasing oxygen adsorption with increasing plasma power and treatment time, without changing Sn oxidation. With the lowest plasma powers and treatment times, however, H2O plasma treatment results in nearly complete bulk Sn reduction. Although both plasma systems increased oxygen adsorption over the untreated materials, there were clear differences in the tin and oxygen as well as morphological variations upon plasma treatment.

Synthesis of hierarchical worm-like SnO2@C aggregates and their enhanced lithium storage properties

The present paper reports a synthetic strategy of hierarchical worm-like SnO2@C aggregates with enhanced electrochemical performances. Specifically, a glucose-assisted hydrothermal treatment of the intermediate Co–Sn alloy nanoparticles, which were formed by carbothermal reduction of mixed commercial SnO2 and Co3O4 nanoparticles. The SnO2@C sample exhibits enhanced cycling performance in comparison with raw commercial SnO2 nanoparticles and intermediate Co–Sn alloy nanoparticles when used as anode of lithium ion battery. A stable capacity of 533.6mAhg−1 at 100mAg−1 and 477.0mAhg−1 at 400mAg−1 remains after 60 cycles. When the current density increases to 1600mAg−1, the SnO2@C sample still deliver a high capacity of 384.2mAhg−1. The superior electrochemical performances could be attributed to the synergistic effect of unique worm-like aggregates structure and carbon surface-layer, which facilitate the electron transportation and buffer the large volume change.

FeOx-Coated SnO2 as an Anode Material for Lithium Ion Batteries

Nanostructured iron oxide is coated on commercial SnO2 nanoparticles via a simple solution route. The method involves the thermal decomposition of an iron carbonyl complex (Fe(CO)5) in the presence of SnO2 and a surfactant in an organic solvent. The resulting FeOx/SnO2 nanocomposite showed an enhanced performance as an anode material for lithium ion batteries. In a conventional electrolyte containing 5 wt % fluoroethylene carbonate (FEC), a composite FeOx/SnO2 (∼1:3 mol ratio) exhibited a stable capacity ∼480 mAh/g (at a rate of 400 mA/g) for up to 150 cycles compared with <130 mAh/g for bare SnO2. The enhanced cycle performance of FeOx/SnO2 is attributed to (i) the in situ formation of electronically conductive nanostructured Fe/Li2O matrix and (ii) the formation of better-preserved solid–electrolyte interface in the presence of FEC.

Reactive and photocatalytic degradation of various water contaminants by laser ablation-derived SnOx nanoparticles in liquid

Reactive non-stoichiometric tin oxide (SnOx) nanoparticles were facilely obtained by laser ablation of Sn in water using a fundamental nanosecond pulse laser. The size of the primary nanoparticles increased and the crystallinity spontaneously improved without heat treatment when the colloidal solutions were aged in the dark. Interestingly, such ageing-induced self-crystallization processes were considerably different from those in the colloidal solution illuminated by sunlight and/or ultraviolet light. Both the primary amorphous SnOx nanoparticles and the aged nanocrystals were used for water purification; the contaminants studied included methyl orange, methylene blue, pentachlorophenol, and dichromate. All removal treatments produced good results, and had high degradation rates. Comparison with experimental investigations revealed that nanoparticles synthesized using conventional methods, such as sol–gel synthesis, showed poor performance or had no effect on the removal of water contaminants. In contrast, SnOx nanoparticles derived by laser ablation in liquid possessed high surface reactivity, and the corresponding aged nanocrystals exhibited enhanced photocatalytic activity compared with commercial SnO2 nanoparticles. These materials may be used in wastewater purification.