Mesoporous nanocomposite sensors based on Sn1-xCexO2-δ metastable solid solution with high percentage of Ce3+ valence state for selective detection of H2 and CO

Abstract

[EN] Mesoporous nanocomposite materials based on Sn1-xCexO2-delta (x = 0.1; 0.2; 0.3) solid solution were synthesized by a hydrothermal synthesis route using CTAB-ionic surfactant-as template, for testing their sensing properties for selective detection of H-2 and CO. The samples were investigated with respect to their structural composition, nanocrystallitesizes, morphology, texture, molecular and macroscopic surface properties by XRD, Raman, SEM-EDX, HRTEM and STEM-EDX mapping, BET analysis and XPS, as a function of the ceria content incorporated in the mentioned solid solution. A high percentage of Ce3+ valence state (similar to 40%) was determined by XPS for the Sn0.9Ce0.1O2-delta surface sample. A clear morphology of dispersed nanoparticles, with uniform grain sizes around 5 nm was revealed by HRTEM, while the organization of the nanoparticles in a mesoporous architecture was confirmed by BET analysis. Gas sensing investigations revealed the role of the mesoporous architectures, solid solution phases, Ce3+ oxidation state relative concentration on the increase in sensitivity for the selective detection of H-2 and CO. (C) 2013 Elsevier Inc. All rights reserved.