Biomass-derived graphitic carbon/MoO3 nanosheets-crosslinked tubes for high response and rapid detection of butyl mercaptan at low temperatures

Abstract

The fabrication of gas sensors for monitoring volatile organic sulfur compounds has currently gained wide concerns, but no related works on butylmercaptan (BM) were reported. Herein, two types of MoO₃ materials were prepared by simple immersion of willow branch slices in ammonium molybdate water/acetonitrile solution followed by air calcination. The GC/MoO₃ nanosheets-crosslinked tubes obtained from calcining precursor at 450 °C involve 5.45 wt% biomass-derived graphitic carbon (GC), and possess multi-level mesopores, large specific surface area and abundant oxygen vacancy defects. These structural features can increase the electroconductivity and percentage of oxygen species adsorbed on sensing surface, promote the rapid transport and adsorption of reducing BM molecules in sensing layer. Under the catalytic synergy of surface Mo⁶⁺ ions, highly sensitive detection of harmful BM gas by semiconductor sensor at different low temperatures is achieved for the first time. At near room temperature of 50 °C, GC/MoO₃ sensor realized a response value (RV) of 174.8 for 50 ppm BM and it also had a good response (RV = 79) to the same concentration of BM at 92 °C. Meanwhile, it possessed reversible response-recovery and other good overall sensing performances. In addition, the low-temperature sensing mechanism of enhanced BM was analyzed in combination with DFT calculation.