Preparation of mesoporous tin oxide for electrochemical applications

Abstract

Mesoporous tin oxide stable up to 500 °C has been prepared for the first time using both cationic and neutral surfactants.Following the discovery of the MCM family of mesoporous silicates using the supramolecular templating approach, 1 mesoporous materials have attracted considerable attention because of their remarkably large surface areas and narrow pore size distributions, which make them ideal candidates for catalysts, molecular sieves, and as electrodes in solid-state ionic devices. A number of related synthetic strategies have been developed and a variety of materials, in terms of both composition and structure, have been prepared. [2][3][4] Tin oxide is a wide-energy-gap semiconductor and has been widely used as a catalyst for oxidation of organic compounds, and for applications such as solid-state gas sensors, rechargeable Li-batteries, and optical electronic devices. The success in many of these applications relies critically on the preparation of crystalline SnO 2 with uniform nanosize pore structure. Consequently, the synthesis of thermally stable mesoporous SnO 2 is of great importance.To date, several preparative approaches utilizing a supramolecular templating mechanism have been reported for the preparation of mesoporous tin oxide. [5][6][7] Upon removal of the surfactant, however, the mesoporous structures were destroyed; in other words, the preparation of mesoporous SnO 2 without the support of a surfactant has not yet been achieved. For example, upon hydrolysis of SnCl 4 in the presence of sodium dioctylsulfosuccinate (AOT, an anionic surfactant), Rao and Ulagappan 5 obtained a mesoporous SnO 2 -AOT material with an average pore size of 3.2 nm. Attempts to remove the surfactant either by calcination at ca. 400 °C or by solvent extraction, however, resulted in collapse of the mesoporous structure. Similarly, upon hydrolysis of SnCl 4 in the presence of sodium dodecyl sulfonate (another anionic surfactant), Qi et al. 6 obtained mesoporous tin oxide with an average pore size of 4.1 nm. Again, the mesostructure collapsed when the surfactant was removed at 400 °C. Starting with tin isopropoxide and tetradecylamine (a neutral surfactant), Pinnavaia and coworkers 7 obtained mesoporous tin oxide with an average pore size of 5.6 nm. The mesoporous structure was stable up to 350 °C, but was destroyed upon calcination at 400 °C and the surface area was greatly reduced.For electrochemical applications such as gas sensors, however, thermal stability of a mesoporous structure at high temperatures and without the support of a surfactant is critical for high catalytic reactivity, fast charge and mass transport, and long-term microstructural stability and durability. Thus, the objective of this study was to develop synthesis procedures for the preparation of mesoporous SnO 2 , stable at high temperatures ( > 400 °C), without the support of a surfactant. We have explored both neutral (S 0 I 0 ) and electrostatic (S + I 2 ) templating approaches to prepare mesoporous SnO 2 .In the neutral templating approach, †...

Reversible and High‐Capacity Nanostructured Electrode Materials for Li‐Ion Batteries

“…In spite of these disadvantages, nanostructured SnO 2 has been intensively investigated because of its good capacity retention and high rate capability depending on its morphology, and hollow structures, nanowires, mesopores, and nanorods have been reported. [19][20][21][22][23][24][25][26] Hollow and nanowire SnO 2 showed improved capacity retention, compared with the bulk analogues. [21][22][23][24] However, when the bulk particles contain ordered mesopores, these pores act as a buffer layer for volume changes of the pore wall; indeed, mesoporous and crystalline tin phosphate composites showed excellent capacity retention, demonstrating another means of controlling the volume expansion/contraction.…”

Template-free hydrothermal synthesis of single-crystalline SnO2 nanocauliflowers and their optical properties

“…To prepare SnO 2 with different morphologies, a variety of techniques have been widely investigated such as sol-gel, CVD, coprecipitation, hydrothermal/solvothermal, and surfactant-assisted methods [12][13][14][15][16]. Compared with these methods, the hydrothermal approach is a better alternative with the advantages in mild synthetic conditions, simple manipulation, and low pollution.…”

Tin Oxide Nanoparticles: Synthesis, Characterization and Study their Particle Size at Different Current Density

“…It has been widely used in many applications such as optoelectronic devices (Kim, et al, 2002) fabricating solar cells (Moustafid, et al, 2002;Okuya, et al, 2001) electrochemical applications (Chen and Liu, 1999), electrode materials for Li-ion batteries (Kim, et al, 2005), catalysts for redox reactions (Chou, et al, 2003;Wierzchowski and Zatorski, 2003) and gas sensors (Moulson and Herbert, 1990;Li, Zhang and Kawi, 1999). Due to its high sensitivity to reduce as well as to oxidize gases, SnO 2 has been used as the predominant sensing material in the field of solidstate gas sensors for environmental monitoring of CO, H 2 , and NO.…”