SnO2 Composites Research Articles

Oxygenated VOC Detection Using SnO2 Nanoparticles with Uniformly Dispersed Bi2O3

Bi2O3 particles are introduced as foreign additives onto SnO2 nanoparticles (NPs) surfaces for the efficient detection of oxygenated volatile organic compounds (VOCs). Bi2O3-loaded SnO2 materials are prepared via the impregnation method followed by calcination treatment. The abundant Bi2O3/SnO2 interfaces are constructed by the uniform dispersion of Bi2O3 particles on the SnO2 surface. The results of oxygen temperature-programmed desorption suggest that Bi2O3-loaded SnO2 samples display improved surface oxygen ions than neat-SnO2 NPs. As a result, the gas sensor based on 1 mol% Bi2O3-loaded SnO2 (1Bi-L-SnO2) composites shows significantly higher sensitivity and a faster response speed toward various oxygenated VOCs compared with SnO2, especially at 200 °C and 250 °C. The results of catalytic combustion and temperature-programmed reaction measurements reveal the dominant role of adsorption and partial oxidation during ethanol combustion on SnO2 and 1Bi-L-SnO2 surfaces. In this case, the improvement in the sensing performance of the 1Bi-L-SnO2 sensor can be associated with the increase in surface oxygen ions at Bi2O3/SnO2 interfaces. The results confirm the significant role of surface functionalization for sensing materials. The obtained outstanding sensing performance provides the potential application for the simultaneous detection of total oxygenated VOCs in practice.

Stepwise emergence of CO gas sensing response and selectivity on SnO2 using C supports and PtOx decoration.

Room temperature gas sensing is crucial for practical devices used in indoor environments. Among various materials, metal oxides are commonly used for gas sensing, but their strong insulating properties limit their effectiveness at room temperature. To address this issue, many studies have explored diverse methods such as nanoparticle decoration or conductive support, etc. Here, we report the emergence of gas-sensing functionality at room temperature with improved CO gas selectivity on SnO2 nanoparticles through sequential steps by using amorphous carbon (a-C) support and PtOx decoration. The SnO2 decorated on amorphous carbon shows enhanced gas adsorption compared to inactive gas sensing on SnO2 decorated carbon support. The higher Vo site of SnO2 on a-C induces gas adsorption sites, which are related to the higher sp2 bonding caused by the large density of C defects. The ambiguous gas selectivity of SnO2/a-C is tailored by PtOx decoration, which exhibits six values of sensing responses (Rg/Ra or Ra/Rg) under CO gas at room temperature with higher selectivity. Compared to PtOx/a-C, which shows no response, the enhanced CO gas sensing functionality is attributed to the CO adsorption site on PtOx-decorated SnO2 particles. This report not only demonstrates the applicability of CO gas sensing at room temperature but also suggests a strategy for using SnO2 and carbon compositions in gas sensing devices.

Multifunctional conductive SA/ATO@TiO2 whisker aerogels for piezoresistive pressure sensor application

Ultralight and flexible aerogel sensors have garnered significant interest, yet challenges persist in developing their high elasticity and exceptional piezoresistive properties. In this work, laminated porous composite aerogels have been successfully prepared by a composite of sodium alginate (SA) and antimony-doped SnO2 coated titanium dioxide whiskers (ATO@TiO2) via directional freezing technique. The resulting SA and ATO@TiO2 (SAT) aerogels with laminated porous structure demonstrate lightweight with low-density (0.06 g·cm−3), good compressive properties, superplastic, and conductive properties. The incorporation of small amounts of rod-like ATO@TiO2 whiskers into SAT aerogels not only enhances its electrical conductivity and thermal insulation, but also imparts a light-colored appearance to the aerogel. The assembled SAT aerogel sensors exhibit high sensitivity within 1.0 kPa (225 kPa−1, 17.86 kPa−1) and maintains excellent fatigue resistance even over 1000 cycles. The temperature-responsive properties of SAT aerogel sensors presented superior thermal insulation properties, and it can operate properly even at a high temperature of 100 °C. More importantly, SAT piezoresistive sensors facilitated real-time monitoring and human-computer interactive activities related to human movement and health, showcasing significant potential in diverse fields.

MXene (Ti3C2Tx)/Rh-doped SnO2 composites for improved acetone sensing properties

Rh-doped SnO2 nanofibers have demonstrated high selectivity and response in detecting acetone. However, these nanofibers operated at high temperature and exhibited a long recovery time. In this study, a two-dimensional material MXene was introduced into Rh-doped SnO2 nanofibers, and MXene (Ti3C2Tx)/Rh–SnO2 composites were synthesized via hydrothermal method. The morphology, structure and composition of MXene (Ti3C2Tx)/Rh–SnO2 were systematically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller techniques (BET). The results indicated that MXene (Ti3C2Tx)/Rh–SnO2 composites formed compact heterostructures. The effects of adding different volumes (0.5, 1, 1.5, and 2 ml) of 5 mg/ml MXene on the sensing properties of the composites were investigated. The sensing results showed that the composite of (1 ml) MXene (Ti3C2Tx)/Rh–SnO2 achieved a response as high as 82.46 % to 100 ppm acetone gas at 100 °C and exhibited rapid response and recovery times of 3/8 s, compared to the optimal operating temperature (190 °C) and recovery time (43 s) observed with the pristine Rh-doped SnO2 nanofibers, there is a significant improvement. It also demonstrated outstanding humidity resistance and a minimum detection limit of 0.6 ppm. Moreover, the addition of MXene not only significantly affects the sensing performance of the pristine Rh-doped SnO2 nanofibers but also preserves its sensing advantages. The sensing mechanism of the MXene (Ti3C2Tx)/Rh–SnO2 composites is also discussed. Herein, MXene (Ti3C2Tx)/Rh–SnO2 composites presents a feasible strategy for enhancing the sensing properties of gas sensors.

Exploring the potential of green synthesized ZnO-SnO2 composite as an effective electron transport layer for perovskite solar cells: A sustainable approach

Utilizing green-synthesized ZnO nanoparticles as an electron transport layer (ETL) is a key strategy in perovskite solar cell applications, leveraging their high electron mobility, conductivity, stability against photo-corrosion, and cost-effectiveness. In this study, these environmentally synthesized nanoparticles, combined with SnO2, formed a composite solution-processed ETL achieving an impressive 18.09 % device efficiency, with 1.06 V open circuit voltage, 71.71 % fill factor, and 23.80 mA/cm2 short circuit current density. These values underscore the composite material's potential for device applications. Additionally, capacitance measurements investigated ETL and absorber layer interfaces, yielding crucial insights into their behaviour under varying voltage, frequency, and illumination conditions. The study highlights the ZnO-NP and SnO2 composite's efficacy as a superior ETL in PSCs, emphasizing the environmental sustainability implications of employing green-synthesized materials in solar energy technologies.

Preparation and properties study of high performance Eu2Sn2O7–SnO2 composites humidity sensor

In the work, a high-performance Eu2Sn2O7–SnO2 (ES-2) humidity sensors were prepared through a one-step hydrothermal method. Eu2Sn2O7 is a bimetallic material can increase the adsorption capacity to water molecules and promote electron transfer, thus improving the sensitivity of the sensor. The introduction of Eu2Sn2O7 promotes the increase of the content of oxygen vacancies in the ES-2 composite material, which promotes the accelerated decomposition of water molecules, and facilitates the formation of the chemisorbed layer to improve the sensitivity of the sensor and the response time. The increase in specific surface area of ES-2 provided more adsorption sites for H2O and also provided a good transport channel for water molecules to diffuse into the interior of the material. ES-2 humidity sensor exhibits high sensitivity (22,405 ± 363), small humidity hysteresis (1 ± 0.3 %), short response/recovery time (7/6 ± 0.5 s), good repeatability and stability (11%–95 % RH). This study not only promotes the development of SnO2-based humidity sensors, but provides new ideas for the preparation of high-performance humidity sensors.

Advanced degradation of organic pollutants using sonophotocatalytic peroxymonosulfate activation with CoFe2O4/Cu- and Ce-doped SnO2 composites

The rampant upsurge of organic pollutants in aqueous media has become one of the major concerns nowadays. Finding non-specific catalysts that can target a wide range of organic pollutants is a key challenge. Eco-friendly oxidative radicals, such as promoted by peroxymonosulfate (PMS), are necessary for efficient water decontamination. We propose a multicomponent composite catalyst for activating PMS using a dual strategy of sonophotocatalysis. The composite integrates cobalt ferrite and Cu- or Ce-doped SnO2, with the at. % of doping metal and the mixture ratio carefully balanced. The top-performing architectures were able to decompose rhodamine B (20 ppm), a representative pollutant, in under 3 min and achieve over 70% mineralization in just 5 min. The synthesized nanocomposites demonstrated exceptional sonophotocatalytic performance, even when treating complex and diverse multipollutant solutions (80 ppm), achieving over 75% mineralization after 150 min. Considering their high stability and reusability, the proposed CoFe2O4/Cu- and Ce-doped SnO2 materials are among the state-of-the-art heterogeneous catalysts for mineralizing organic pollutants through PMS activation.

Discerning the catalytic treatment of cationic dye wastewater in photoreactor comprising ternary (Co3+/Co2+)-embedded SnO2/ZnFe2O4 composite sensitive toward ultra-violet illumination.

Herein, magnetic (Co3+/Co2+)-integrated SnO2, SnO2/ZnFe2O4, and ZnFe2O4 composites have been prepared from triply distilled water and 30% of isopropanol in the water medium. The phase evolution, microstructure, and magnetism were investigated successfully and tested for cationic dye wastewater degradation containing Rhodamine 6G and Methylene Blue under ultra-violet irradiation. Composite spheres are attributed to efficient heterojunction interfaces between ZnFe2O4 and SnO2 semiconductors with the support of (Co3+/Co2+) nanoparticles. The results provide a simple, low-cost, environmentally friendly, and scalable method of ternary composites to degrade mixed dyes. Co3+/Co2+-implanted SnO2/ZnFe2O4 offered narrowed bandgap energy, more light absorption, diminishing electron-hole recombination, and more charge carriers toward cationic dye wastewater than the binary components. The rate constant of Rhodamine 6G degradation was observed at 0.0237min-1, and Methylene Blue degradation was observed at 0.0187min-1 at 90min under UV (λ = 365nm) irradiation. Capturing studies of various organic reactive species and mechanisms of composites was also proposed in detail.

SnO2 QDs loaded α-Fe2O3 hollow cubes for H2S room temperature detection and insights into their gas sensing mechanism

Since H2S gas is flammable and explosive, it has significance to realize H2S detection at room temperature. In this work, different amounts of SnO2 quantum dots (QDs) were loaded on Prussian blue derived α-Fe2O3 hollow cubes, which exhibits an uneven porous granular surface structure evidenced by characterization of TEM and SEM. Aiming H2S as target gas, the α-Fe2O3/SnO2 composites demonstrate greatly improved gas sensing performance at room temperature. Specifically, the response value of S1 to S4 (different SnO2 QDs loads) to 5 ppm H2S at room temperature are 4.97, 5.76, 8.21 and 6.69 respectively, which has a trend from rise to decline as the SnO2 QDs increases. Optimum sensitivity is achieved by 10 wt% SnO2 loading. Finally, characterizations such as BET, XPS and DRIFTS et al. reveal that the effective electron transfer from SnO2 to α-Fe2O3 via energy band match promotes the chemisorption oxygen and density and mobility of charge carriers, which is beneficial to H2S gas sensing.

Regulation of domain wall motion in PZT-based ceramics through the introduction of local stress fields

At present, a big challenge exists yet in the piezoelectric ceramic material that high piezoelectric performance and low losses (large Qm and low tanδ) are difficult to achieve concurrently due to the effects of domain switching and domain wall motion on electromechanical properties. In this work, by introducing secondary-phase particles (SnO2 particles) into the hard PZT matrix, we successfully build local stress fields in the ceramic. These local stress fields not only pin the domain and domain wall but also diminish the domain size and increase the domain wall density. The former is in favor of reducing the losses, while the latter is beneficial to promoting the piezoelectric properties. Thus, the optimized piezoelectric properties and losses in the ceramic can be obtained simultaneously. The results show that in the PZT/0.3 wt%SnO2 composite, the mechanical quality factor reaches 2800 and the dielectric loss is only 0.4 %, which are superior to the hard PZT matrix. Meanwhile, the composite ceramic has a high piezoelectric constant of 390 pC/N. These excellent properties will push the development of next-generation high-power electromechanical devices.

Fabrication of and corrosion prevention mechanisms of tin oxide (SnO2) decorated reduced graphene oxide (rGO) for anodic protection of Zn metal surfaces

The hydrothermal approach was utilized to prepare SnO2 and rGO-SnO2 composite, and its physicochemical properties and corrosion resistance application are examined in this study. The results suggest that the SnO2, rGO-SnO2 composite exhibits a well-defined and uniform morphology, with SnO2 NPs homogeneously distributed and anchored on the rGO. XRD analysis confirms the crystalline tetragonal structure with 19.1 nm and 20.8 crystalline size. Further, the corrosion resistance application of the rGO-SnO2 composite is evaluated through electrochemical measurements, such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The composite-coated substrate is subjected to NaCl electrolyte using a Zn plate. The corrosion performance is compared with that of bare Sn and rGO-SnO2 counterparts to assess the synergistic effect of the composite which exhibits enhanced anticorrosion properties. The synergistic effect of Sn and rGO in the composite offers superior corrosion resistance, making it a promising material for various corrosion-prone applications. Overall, the findings contribute to developing novel and effective strategies for combating corrosion, ensuring the durability and reliability of materials in diverse industrial environments.
 KEY WORDS: Sn-rGO composite, Tafel plot, Corrosion protection, Surface analysis, Synergistic effect
 Bull. Chem. Soc. Ethiop. 2024, 38(2), 445-456. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i2.12

Tunable composition of Sn/SnO2@C composites for lithium-ion batteries

Sn-based anodes are the most viable option for lithium-ion batteries (LIBs), but their widespread implementation is hindered by suboptimal kinetics properties and structural failures. Herein, an effective anode material has been synthesized for LIBs, consisting of a carbon-encapsulated matrix with particles of Sn and SnO2 (Sn/SnO2@C) composites. The synergistic effect between SnO2 and Sn significantly improves both mechanical stability and kinetic properties. Additionally, the presence of a carbon matrix enhanced electronic conductivity as well as effectively mitigating volume expansion during cycling. As expected, the Sn/SnO2@C electrode realizes decent cycle stability and impressive rate performance. The work offers a promising approach for enhancing the performance of tin-carbon composites.

Room temperature solid electrolyte ozone sensor based on Ag-doped SnO2

In this paper, SnO2 was synthesized using MOFs as a sacrificial template, and Ag-doped SnO2 composite was synthesized by reducing AgNO3 with NaBH4, and O3 sensors were prepared using sodium superionic conductor (NASICON) as a solid electrolyte. At room temperature, the gas-sensitive experimental tests showed that the response of the sensor with 3 wt% Ag-SnO2 to 180–420 ppb O3 increased by about 57% and the sensitivity increased by 9.9% compared to the pure SnO2 sensor. The repeatability and stability of the 3 wt% Ag-SnO2 sensor were tested at 240 ppb O3, and the results showed that the repeatability of the sensor varied between − 2% and 2%, and the stability varied between − 4% and 4%. Therefore, the solid electrolyte sensor prepared by the excellent Ag-doped SnO2 composite material has a good application prospect in the detection of low-concentration O3.

Zn Doping Improves the Anticancer Efficacy of SnO2 Nanoparticles

Tin dioxide (SnO2) nanoparticles (NPs) can be applied in several ways due to their low cost, high surface-to-volume ratio, facile synthesis, and chemical stability. There is limited research on the biomedical application of SnO2-based nanostructures. This study aimed to investigate the role of Zn doping in relation to the anticancer potential of SnO2 NPs and to enhance the anticancer potential of SnO2 NPs through Z doping. Pure SnO2 and Zn-doped SnO2 NPs (1% and 5%) were prepared using a modified sol–gel route. XRD, TEM, SEM, EDX, UV-Vis, FTIR, and PL techniques were used to characterize the physicochemical properties of produced NPs. XRD analysis revealed that the crystalline size and phase composition of pure SnO2 increased after the addition of Zn. The spherical shape and homogenous distribution of these NPs were confirmed using TEM and SEM techniques. EDX analysis confirmed the Sn, Zn, and O elements in Zn-SnO2 NPs without impurities. Zn doping decreased the band gap energy of SnO2 NPs. The PL study indicated a reduction in the recombination rate of charges (electrons/holes) in SnO2 NPs after Zn doping. In vitro studies showed that the anticancer efficacy of SnO2 NPs increased with increasing levels of Zn doping in breast cancer MCF-7 cells. Moreover, pure and Zn-doped SnO2 NPs showed good cytocompatibility in HUVECs. This study emphasizes the need for additional investigation into the anticancer properties of Zn-SnO2 nanoparticles in various cancer cell lines and appropriate animal models.

Facile Synthesis of a Multifunctional SnO2 Nanoparticles/Nanosheets Composite for Dye-Sensitized Solar Cells.

Synthesizing SnO2 composite nanostructures via a facile one-step method has been proven to be a great challenge. By adjusting operating variables, such as the reaction solution's pH and solvent type, several SnO2 nanostructures, in particular, a function-matching SnO2 hybrid structure composed of irregular zero-dimensional nanoparticles (NPs) and two-dimensional nanosheets (NSs), could be created. The as-prepared SnO2 composites were then characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and diffuse reflectance spectroscopy (DRS) to determine their physical properties. Dye-sensitized solar cells (DSCs) constructed with the resultant multifunctional SnO2 NPs/NSs composite exhibited the highest overall power conversion efficiency (PCE) of 5.16% among all products with a corresponding short-circuit current density of 18.6 mA/cm2 and an open-circuit voltage of 0.626 V. The improved performance can be attributed to the combined effects of each component in the composite, i.e., the intentionally introduced nanosheets provide desired electron transport and enhanced light scattering capability, while the nanoparticles retain their large surface area for efficient dye absorption.

A hybrid mesoporous composite of SnO2 and MgO for adsorption and photocatalytic degradation of anionic dye from a real industrial effluent water.

Water pollution by synthetic anionic dyes is one of the most critical ecological concerns and challenges. Therefore, there is an urgent need to find an efficient adsorbent and photocatalyst for dye removal. In the present study, we aimed to fabricate a hybrid mesoporous composite of spongy sphere-like SnO2 and three-dimensional (3D) cubic-like MgO (SnO2/MgO) as a promising adsorbent/photocatalyst to remove the anionic sunset yellow (SSY) dye from real wastewater at neutral pH conditions. The as-synthesized SnO2 and MgO composite was investigated using XRD, SEM, EDX, TEM, XPS, BET, and zeta potential. The experimental study of the SSY removal using SnO2/MgO composite was performed at different conditions, such as pH, stirring time, dose, and temperature. More than 99% of 10 mg/L SSY was effectively adsorbed from aqueous solution using 40 mg of SnO2/MgO composite at pH 7 and a stirring time of 60 min. The SSY adsorption behavior was well fitted by pseudo-second order and the Langmuir model, indicating that the SSY was chemisorbed to the composite-active sites as a monolayer. On the other hand, photocatalytic degradation process exhibited better results in terms of speed of removal and used quantity of photocatalyst, where 20 mg of SnO2/MgO composite can be used to remove > 99% of SSY dye within 30 min. Mechanism of SSY adsorption and photocatalytic degradation was discussed. In addition, elution experiments demonstrated that the SnO2/MgO composite as an SSY adsorbent could be reused for nine cycles without considerable reduction in the SSY adsorption efficiency. Therefore, this work exhibited that the mesoporous SnO2/MgO composite can be considered an effective adsorbent/photocatalyst to remove SSY dye from real industrial effluent water at neutral pH conditions.

Heterostructured Co3O4–SnO2 composites containing oxygen vacancy with high activity and recyclability toward NH3BH3 dehydrogenation

Heterostructured Co3O4–SnO2 composites containing oxygen vacancy with high activity and recyclability toward NH3BH3 dehydrogenation

Structural, optical, and dielectric characteristics of pulsed laser deposited SnO2-TiO2 composite thin films

Pulsed laser deposition was used to fabricate the thin films of SnO2 and SnO2-TiO2 composites on FTO substrates and these films were characterized to understand the effect of TiO2 on the structural, optical, and electrical properties of SnO2. The Tauc plots confirm that the composite films have a higher band gap energy than SnO2. EDX spectra demonstrate that the thin films contain Ti, Sn, and O ions. The photoluminescence (PL) spectra indicate three blue emission bands at wavelengths of 410, 435, and 460 nm and these are due to the oxygen vacancies or interstitial oxygen ions and defect-related states. These films are n-type semiconductors as verified by the Hall Effect measurements. At the interface of the film, the frequency dependence of the dielectric at room temperature reveals that as the frequency increases, the dielectric constant and dielectric losses decrease. SnO2 film has a significantly higher a.c. conductivity than the SnO2-TiO2 composite films. The correlated barrier hopping (CBH) mechanism is responsible for the conduction behaviour and obeys Johncher’s power law (n < 1). The addition of TiO2 in SnO2 affects the structural, optical, dielectric, and ac conductivity of films at room temperature.

Synergistic Effect of Oxygen Vacancy-Rich SnO2 and AgCl in the Augmentation of Sustained Oxygen Reduction Reaction.

Developing a stable and methanol-tolerant electrocatalyst for a sustained oxygen reduction reaction (ORR) is of great importance for advancing direct methanol fuel cell applications. The silver-based electrocatalysts are particularly interesting among the promising non-Pt-based electrocatalysts for ORR. Herein, we report a single-step synthesis of a composite of AgCl and SnO2 with oxygen vacancy (AgCl-SnO2(VO)), which exhibits sustained and selective catalytic activity for the ORR along with excellent durability. Hydrothermal synthesis generates oxygen vacancies within the material and facilitates a strong interaction between AgCl and SnO2(VO), which effectively augments the ORR activity and the long-term stability of the composite. The composite exhibits remarkable methanol tolerance, as evidenced by a meager shift of only 0.002 V in the half-wave potential. Furthermore, the composite demonstrates excellent durability, with no noticeable changes in onset and half-wave potential even after 2500 cycles. The cost-effectiveness, durability, and ORR selectivity of this composite hold great promise toward contributing to the advancement of clean energy technology.

Highly Active Interfacial Sites in SFT‐SnO2 Heterojunction Electrolyte for Enhanced Fuel Cell Performance via Engineered Energy Bands: Envisioned Theoretically and Experimentally

Extending the ionic conductivity is the pre‐requisite of electrolytes in fuel cell technology for high‐electrochemical performance. In this regard, the introduction of semiconductor‐oxide materials and the approach of heterostructure formation by modulating energy bands to enhance ionic conduction acting as an electrolyte in fuel cell‐device. Semiconductor (n‐type; SnO2) plays a key role by introducing into p‐type SrFe0.2Ti0.8O3‐δ (SFT) semiconductor perovskite materials to construct p‐n heterojunction for high ionic conductivity. Therefore, two different composites of SFT and SnO2 are constructed by gluing p‐ and n‐type SFT‐SnO2, where the optimal composition of SFT‐SnO2 (6:4) heterostructure electrolyte‐based fuel cell achieved excellent ionic conductivity 0.24 S cm−1 with power‐output of 1004 mW cm−2 and high OCV 1.12 V at a low operational temperature of 500 °C. The high power‐output and significant ionic conductivity with durable operation of 54 h are accredited to SFT‐SnO2 heterojunction formation including interfacial conduction assisted by a built‐in electric field in fuel cell device. Moreover, the fuel conversion efficiency and considerable Faradaic efficiency reveal the compatibility of SFT‐SnO2 heterostructure electrolyte and ruled‐out short‐circuiting issue. Further, the first principle calculation provides sufficient information on structure optimization and energy‐band structure modulation of SFT‐SnO2. This strategy will provide new insight into semiconductor‐based fuel cell technology to design novel electrolytes.