Zirconia-Doped Methylated Silica Membranes via Sol-Gel Process: Microstructure and Hydrogen Permselectivity

Abstract

In order to obtain a steam-stable hydrogen permselectivity membrane, with tetraethylorthosilicate (TEOS) as the silicon source, zirconium nitrate pentahydrate (Zr(NO3)4·5H2O) as the zirconium source, and methyltriethoxysilane (MTES) as the hydrophobic modifier, the methyl-modified ZrO2-SiO2 (ZrO2-MSiO2) membranes were prepared via the sol-gel method. The microstructure and gas permeance of the ZrO2-MSiO2 membranes were studied. The physical-chemical properties of the membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and N2 adsorption–desorption analysis. The hydrogen permselectivity of ZrO2-MSiO2 membranes was evaluated with Zr content, temperature, pressure difference, drying control chemical additive (glycerol) content, and hydrothermal stability as the inferred factors. XRD and pore structure analysis revealed that, as nZr increased, the MSiO2 peak gradually shifted to a higher 2θ value, and the intensity gradually decreased. The study found that the permeation mechanism of H2 and other gases is mainly based on the activation–diffusion mechanism. The separation of H2 is facilitated by an increase in temperature. The ZrO2-MSiO2 membrane with nZr = 0.15 has a better pore structure and a suitable ratio of micropores to mesopores, which improved the gas permselectivities. At 200 °C, the H2 permeance of MSiO2 and ZrO2-MSiO2 membranes was 3.66 × 10−6 and 6.46 × 10−6 mol·m−2·s−1·Pa−1, respectively. Compared with the MSiO2 membrane, the H2/CO2 and H2/N2 permselectivities of the ZrO2-MSiO2 membrane were improved by 79.18% and 26.75%, respectively. The added amount of glycerol as the drying control chemical additive increased from 20% to 30%, the permeance of H2 decreased by 11.55%, and the permselectivities of H2/CO2 and H2/N2 rose by 2.14% and 0.28%, respectively. The final results demonstrate that the ZrO2-MSiO2 membrane possesses excellent hydrothermal stability and regeneration capability.

A Review of the Recent Advances in Composite Membranes for Hydrogen Generation Technologies

“…33,34,36 However, the surfactant carbonization route did not allow pore size tuning of the silica structure for targeted applications. 37 38 The materials' pore size distribution and average pore size increased after ZrO 2 doping, demonstrating that ZrO 2 expanded the pores. ZrO 2 −MSiO 2 membranes showed good pore structure and micropore/mesoporous ratio, improving natural gas permeance.…”

“…Wang et al prepared ZrO 2 –MSiO 2 membranes to improve SiO 2 membrane steam stability and H 2 perm selectivity . The materials’ pore size distribution and average pore size increased after ZrO 2 doping, demonstrating that ZrO 2 expanded the pores.…”

Optimized preparation of MgO-ZrO2 nanocomposite powders by assisted sol-gel method

“…Zirconia powders are essential for the performance of zirconia ceramics. Methods for the preparation of zirconia powders include solid phase, hydrothermal, and sol-gel methods [8][9][10][11][12]. In addition, in the preparation of zirconia powders by traditional methods such as the solid phase method, there are often highlighted problems such as non-uniform mixing of raw materials and easy growth of grains, which are not conducive to the performance of the products.…”

“…Although the hydrothermal IOP Publishing doi:10.1088/1742-6596/2390/1/012050 2 method can prepare nanopowders, the reaction is conducted under high temperature and pressure conditions, the preparation process has a certain degree of danger, and it is not easy to achieve large-scale production. However, the sol-gel method not only produces zirconia powders with uniform components, good crystallinity, small particle size, and narrow particle size distribution, but also has the advantages of a simple preparation process and high production efficiency [11,12].…”

Development of Functional Nanomaterials for Applications in Chemical Engineering

“…Liu et al [ 4 ] fabricated 2D R-P type (PEA) 2 (MA) 2 Pb 3 I 10 perovskite films on quartz substrates and studied their terahertz and ultrafast photoelectric response characteristics, demonstrating their potential applications in solar cells and photoelectric devices. Wang and coworkers [ 5 ] prepared methyl-modified ZrO 2 -SiO 2 (ZrO 2 -MSiO 2 ) membranes via the sol–gel method and characterized their physical–chemical properties. With excellent hydrothermal stability and regeneration capability, the ZrO 2 -MSiO 2 membranes have significant potential in steam-stable hydrogen permselective applications.…”