Fabrication of polythiophene/graphitic carbon nitride IDE sensors for exceptional room temperature hydrogen sensitivity

A novel chemi-resistive hydrogen gas sensor was fabricated from polythiophene/graphitic carbon nitride nanocomposite (PTh/g-C3N4) and its hydrogen sensing capability was systematically investigated at room temperature. PTh/g-C3N4 was synthesized by combining thermal exfoliation followed by cost effective in-situ chemical oxidative polymerization method and it was confirmed by spectroscopic and morphological characterization techniques such as FT-IR, XRD, SEM/EDX, TEM, and Raman spectroscopy. The mesoporous architecture of PTh/g-C3N4 nanocomposite offers large surface area and more binding sites as confirmed by BrunauerEmmett-Teller (BET) analysis. This plays a prominent role in upgrading the H2 sensing signal. Specifically, the optimized IDE sensor based on the PTh/g-C3N4 exhibits 5.77 times greater response (29.3% of sensitivity) towards H2 gas compared to the bare g-C3N4 nanosheet (5.07% of sensitivity) under 1 vol% of H2 at room temperature (RT). For both g-C3N4 and PTh/g-C3N4 sensors, the responses are linear and the R-squared correlation coefficient (R2) of the composite based IDE sensor towards 10000 ppm of H2 is 0.9981. The best response time and recovery time of the composite IDE sensor are 83s and 69s at 1 vol% of H2, respectively that is shorter than that of bare g-C3N4 (99s/267s). The outstanding repeatability, good response, and recovery time of the PTh/gC3N4 nanocomposite sensor were mainly due to the win-win choice to combine g-C3N4 and PTh and the formation of a cloudy sheet-like structure with high porosity bestow more active sites to trap hydrogen atoms on the top of the composite. The present attempt is a potential for the use of extremely reliable and effective hydrogen gas sensors for H2 leakage tracing in order to avert any fatal accidents.