Utilizing e-waste: Development of a room temperature ammonia sensing device featuring highly crystalline GdInO3 nanoballs on surface-active g-C3N4 Nanosheets

Advanced recycling methods are utilized to convert electronic waste into premium-grade products, highlighting its potential as a sustainable manufacturing resource. Motivated by the growing interest in 2-dimensional carbon structures and metal oxide nanocomposites, particularly in advancing gas sensor technology, this study embarks on an extensive investigation. The research meticulously examines the direct synthesis of a nanocomposite integrating graphitic carbon nitride (g-C3N4) and perovskite GdInO3, with a focus on its precise sensing capabilities towards ammonia (NH3). Through detailed characterization employing analytical and morphological techniques, the synthesized materials are elucidated. Notably, the nanoball-like morphology of GdInO3 is observed, stemming from the self-assembly of smaller nanoparticles into hierarchical structures, subsequently integrated into the g-C3N4 sheet. Evaluated chips of the e-waste circuit board (e-WCB) modified with the g-C3N4GdInO3 nanocomposite exhibit an impressive response of 72 % towards 10-ppm ammonia, coupled with a response time of 63 seconds and a recovery time of 33 seconds at room temperature with the limit of detection (LOD) of 5.2-ppm. Furthermore, the sensor demonstrates outstanding sensitivity and selectivity towards NH3 compared to other interfering gases. The sensitivity of the composite material towards NH3 was high compared to the pristine materials, this would be because of its enhanced physical and chemical properties (higher active sites and microporosity), therefore the GdInO3-decorated g-C3N4 nanocomposite emerges as a promising candidate for the rapid, sensitive, and selective detection of NH3 under ambient conditions (30 degrees C).