Single-atom silver loaded on tungsten oxide with oxygen vacancies for high performance triethylamine gas sensors†
Traditional sensor materials for detecting gaseous and volatile compounds still have relatively low sensitivity and high price, which limits their large-scale applications. It is critical to improve the changes of sensor resistance vs. the amount of adsorbed target gas by promoting the designed surface reaction. Herein, an atomically deposited Ag on tungsten oxide nanoplate (AD-Ag-WO3) sensor is synthesized by a low temperature deposition method to tackle the existing problems. It is found that the AD-Ag-WO3 is very sensitive when exposed to triethylamine (TEA). Meanwhile, the films showed an unexpectedly high response and low operating temperature due to the deposition of the single-atom silver. Among all of the synthesized materials, 0.01 M AD-Ag-WO3 sensors exhibited far superior gas sensing performance (5150 for 50 ppm at 175 °C) to TEA, which is enhanced 50 times compared with that of pure WO3 (110 for 50 ppm at 250 °C). Simultaneously, the AD-Ag-WO3 sensor also showed an extremely low limit of detection (LLD) (1.7 ppb, far superior to that of traditional materials) and an ultrahigh selectivity for TEA. Such an excellent performance can be ascribed to the presence of single-atom Ag. The synthetic method of loading metal single atoms onto gas-sensitive materials can be extended to other similar composite materials, which opens the way for the industrial application of gas-sensitive sensors induced by designed single-atoms.