One Pot, Two Phases: Individual Orthorhombic and Face-Centered Cubic ZnSnO3 Obtained Synchronously in One Solution

Comprehensive review of micro/nanostructured ZnSnO3: characteristics, synthesis, and diverse applications

Generally, zinc stannate (ZnSnO3) is a fascinating ternary oxide compound, which has attracted significant attention in the field of materials science due to its unique properties such high sensitivity, large specific area, non-toxic nature, and good compatibility. Furthermore, in terms of both its structure and properties, it is the most appealing category of nanoparticles. The chemical stability of ZnSnO3 under normal conditions contributes to its applicability in various fields. To date, its potential as a luminescent and photovoltaic material and application in supercapacitors, batteries, solar cells, biosensors, gas sensors, and catalysts have been extensively studied. Additionally, the efficient energy storage capacity of ZnSnO3 makes it a promising candidate for the development of energy storage systems. This review focuses on the notable progress in the structural features of ZnSnO3 nanocomposites, including the synthetic processes employed for the fabrication of various ZnSnO3 nanocomposites, their intrinsic characteristics, and their present-day uses. Specifically, we highlight the recent progress in ZnSnO3-based nanomaterials, composites, and doped materials for their utilization in Li-ion batteries, photocatalysis, gas sensors, and energy storage and conversion devices. The further exploration and understanding of the properties of ZnSnO3 will undoubtedly lead to its broader implementation and contribute to the advancement of next-generation materials and devices.

Zinc hydroxystannate/zinc-tin oxide heterojunctions for the UVC-assisted photocatalytic degradation of methyl orange and tetracycline

Partial phase modification of zinc hydroxystannate (ZHS) is an effective technique for improving its light absorption capacity. In this study, a zinc hydroxystannate/zinc-tin oxide (ZHS/ZTO) heterostructure was synthesized via chemical co-precipitation followed by annealing. The as-prepared heterostructure revealed cubic crystal morphology along with high-intensity diffraction peaks in the XRD pattern. The XPS analysis of ZHS/ZTO heterostructures demonstrated the presence of key elements (Zn, Sn, and O) in their most stable ionic forms. The photocatalytic degradation efficiencies of the prepared samples were tested against methyl orange (MO) and tetracycline (TC) in an aqueous medium under UVC (254 nm) radiation. Under optimized conditions, maximum degradation efficiencies of 99% for MO and 97% for TC were observed in 120 and 180 min, respectively. Further, the predominant role of OH˙ radicals in the photocatalytic removal of MO and TC was evident through scavenging experiments. 2nd order kinetic model was outperformed in simulating the degradation mechanism of both targets over 1st and zero-order kinetic models. Finally, a photocatalytic degradation mechanism is proposed based on the energy values estimated for the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) using UPS analysis.

Silver Doped Zinc Stannate (Ag-ZnSnO3) for the Photocatalytic Degradation of Caffeine under UV Irradiation

Contaminants of emerging concerns (CECs) spread across a wide range of organic product compounds. As biorecalcitrants, their removal from conventional wastewater treatment systems remains a herculean task. To address this issue, heterogenous solar driven advanced oxidation process based-TiO2 and other semiconductor materials has been extensively studied for their abatement from wastewater sources. In this study, we have synthesized by hydrothermal assisted co-precipitation Ag doped ZnSnO3. Structural and morphological characterizations were performed via X-ray diffraction (XRD), Fourier transform infra-red (FTIR), N2 adsorption-desorption at 77 K by Brunauer-Emmet-Teller (BET) and Barrett, Joyner, and Halenda (BJH) methods, Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy coupled with Energy dispersive spectroscopy (SEM-EDS), and UV-visible absorption in Diffuse reflectance spectroscopy (UV-vis/DRS) mode. Crystallite size estimate for Ag-ZnSnO3 and undoped form was 19.4 and 29.3 nm, respectively, while respective TEM particle size estimate was 79.0 nm and 98.2 nm. BET surface area and total pore volume by BJH for Ag-ZnSnO3 were estimated with respective values of 17.2 m2/g and 0.05 cm3/g in comparison to 18.8 m2/g and 0.06 cm3/g for ZnSnO3. Derived energy band gap (Eg) values were 3.8 eV for Ag-ZnSnO3 and 4.2 eV for ZnSnO3. Photocatalytic performance of Ag-ZnSnO3 was tested towards caffeine achieving about 68% removal under (natural) unmodified pH = 6.50 and almost 100% removal at initial pH around 7.5 after 4 h irradiation. The effect of initial pH, catalyst dosage, pollutant concentration, charge scavengers, H2O2, contaminant inorganic ions (anions) as well as humic acid (HA) on the photocatalyst activity over caffeine degradation were assessed. In accordance with the probation test of the reactive species responsible for photocatalytic degradation process, a reaction mechanism was deduced.

Growth Mechanism of Seed-Layer Free ZnSnO3 Nanowires: Effect of Physical Parameters

ZnSnO₃ semiconductor nanostructures have several applications as photocatalysis, gas sensors, and energy harvesting. However, due to its multicomponent nature, the synthesis is far more complex than its binary counter parts. The complexity increases even more when aiming for low-cost and low-temperature processes as in hydrothermal methods. Knowing in detail the influence of all the parameters involved in these processes is imperative, in order to properly control the synthesis to achieve the desired final product. Thus, this paper presents a study of the influence of the physical parameters involved in the hydrothermal synthesis of ZnSnO₃ nanowires, namely volume, reaction time, and process temperature. Based on this study a growth mechanism for the complex Zn:Sn:O system is proposed. Two zinc precursors, zinc chloride and zinc acetate, were studied, showing that although the growth mechanism is inherent to the material itself, the chemical reactions for different conditions need to be considered.

Seed-Layer Free Zinc Tin Oxide Tailored Nanostructures for Nanoelectronic Applications: Effect of Chemical Parameters

Semiconductor nanowires are mostly processed by complex, expensive, and high temperature methods. In this work, with the intent of developing zinc tin oxide nanowires (ZTO NWs) by low-cost and low-complexity processes, we show a detailed study on the influence of chemical parameters in the hydrothermal synthesis of ZTO nanostructures at temperatures of only 200 °C. Two different zinc precursors, the ratio between zinc and tin precursors, and the concentration of the surfactant agent and of the mineralizer were studied. The type and the crystallinity of the nanostructures were found to be highly dependent on the used precursors and on the concentration of each reagent. Conditions for obtaining different ZTO nanostructures were achieved, namely, Zn₂SnO₄ nanoparticles and ZnSnO₃ nanowires with length ∼600 nm, with the latter being reported for the first time ever by hydrothermal methods without the use of seed layers. Optical and electrical properties were analyzed, obtaining band gaps of 3.60 and 3.46 eV for ZnSnO₃ and Zn₂SnO₄, respectively, and a resistivity of 1.42 kΩ·cm for single ZnSnO₃ nanowires, measured using nanomanipulators after localized deposition of Pt electrodes by e-beam assisted gas decomposition. The low-temperature hydrothermal methods explored here proved to be a low-cost, reproducible, and highly flexible route to obtain multicomponent oxide nanostructures, particularly ZTO NWs. The diversity of the synthesized ZTO structures has potential application in next-generation nanoscale devices such as field effect nanotransistors, nanogenerators, resistive switching memories, gas sensors, and photocatalysis.

Spatial separation of electrons and holes for enhancing the gas-sensing property of a semiconductor: ZnO/ZnSnO3 nanorod arrays prepared by a hetero-epitaxial growth

The construction of semiconductor composites is known as a powerful method used to realize the spatial separation of electrons and the holes in them, which can result in more electrons or holes and increase the dispersion of oxygen ions ([Formula: see text] and O ^- ) (one of the most critical factors for their gas-sensing properties) on the surface of the semiconductor gas sensor. In this work, using 1D ZnO/ZnSnO₃ nanoarrays as an example, which are prepared through a hetero-epitaxial growing process to construct a chemically bonded interface, the above strategy to attain a better semiconductor gas-sensing property has been realized. Compared with single ZnSnO₃ nanotubes and no-matching ZnO/ZnSnO₃ nanoarrays gas sensors, it has been proven by x-ray photoelectron spectroscopy and photoluminescence spectrum examination that the as-obtained ZnO/ZnSnO₃ sensor showed a greatly increased quantity of active surface electrons with exceptional responses to trace target gases and much lower optimum working temperatures (less than about 170 °C). For example, the as-obtained ZnO/ZnSnO₃ sensor exhibited an obvious response and short response/recovery time (less than 10 s) towards trace H₂S gas (a detection limit down to 700 ppb). The high responses and dynamic repeatability observed in these sensors reveal that the strategy based on the as-presented electron and hole separation is reliable for improving the gas-sensing properties of semiconductors.

Synthesis of Orthorhombic Perovskite-Type ZnSnO3 Single-Crystal Nanoplates and Their Application in Energy Harvesting

In recent years, lead-free piezoelectric nanogenerators have attracted much attention because of their great potential for harvesting energy from the environment. Here, we report the first synthesis of two-dimensional (2D) single-crystal ZnSnO₃ hexagon nanoplates and the fabrication of ZnSnO₃ nanoplate-based nanogenerators. The orthorhombic perovskite-structured ZnSnO₃ nanoplates with (111) facets of the exposed plate surface are successfully synthesized via a one-step hydrothermal reaction. Piezoelectric nanogenerators are then fabricated using the as-synthesized single-crystal ZnSnO₃ nanoplates and poly(dimethylsiloxane) (PDMS). A d₃₃ value as high as 49 pC/N for the ZnSnO₃@PDMS composite was obtained without any electrical poling process, which demonstrates that the single-crystal ZnSnO₃ nanoplates have a single-domain structure. To the best of our knowledge, this d₃₃ value is also the highest among lead-free piezoelectric composites. A bending strain can induce the piezoelectric nanogenerator (PENG) to generate a large, stable, and sustainable output open circuit voltage of 20 V and a short circuit current of 0.6 μA, which are higher than many other PENGs. The output signals are sufficient to light a single light-emitting diode (LED), which shows the great potential of the material for scavenging mechanical energy from moving entities, such as road vehicles, railway vehicles, and humans.

Synthesis and characteristics of ZnGa2O4 hollow nanostructures via carbon@Ga(OH)CO3@Zn(OH)2 by a hydrothermal method

Highly uniform and perfectly crystallized ZnGa₂O₄ hollow NSs were successfully fabricated via carbon@Ga(OH)CO₃@Zn(OH)₂ core–shell–shell nanostructures by a two step hydrothermal method.