Synergistic effect of oxygen vacancies and p-n heterojunctions on the isobutanol gas sensing performance of La2O3-SnO2 nanocomposites.

Abstract

A series of La2O3-SnO2 nanocomposites with various Sn/La molar ratios (1:0, 1:0.1, 1:0.2, 1:0.25, and 1:0.3) were successfully fabricated via a simple and efficient solvothermal strategy. Subsequently, their isobutanol-sensing characteristics were systematically assessed. Among all the samples, the composite with a molar ratio of 1:0.25 of Sn to La (SL-0.25) showed the most impressive sensing performance. At the optimal operating temperature of 205 °C, the sensor delivered a response of 71.24 to 100 ppm isobutanol, which is 2997.39% higher than that of pure SnO2. The theoretical limit of detection (LOD) was estimated to be 407 ppb, indicating the potential of the sensor for detecting low concentrations of isobutanol. Beyond its high sensitivity, the optimized sensor also displayed excellent anti-interference capability, good repeatability, and long-term operational stability. The superior sensing characteristics are mainly derived from the cooperative effects of oxygen-vacancy-enhanced surface catalytic activity and heterojunction-induced electronic sensitization within the La2O3-SnO2 composite. Such synergistic effects effectively enhance interfacial charge transport while simultaneously supplying abundant reactive sites for isobutanol adsorption and oxidation reactions. It is expected that these findings will inspire novel design strategies and provide valuable experimental support for the development of high-performance La2O3-SnO2-based isobutanol sensors.

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