Chemiresistive urea sensor based on a composite film of Activated charcoal and Zinc Oxide

Detection of nitrogen content in the form of urea is essential as it confirms its fertility for agricultural practices. Herein, a report on a simple microwave decomposition method for the synthesis of hybrid nanomaterial (Zinc Oxide and Activated Charcoal) that shows a maximum sensitivity of ~87% at 100mM urea concentration with response time and recovery time of 6 min and 80 min, respectively. The urea sensing mechanism with pre-adsorbed oxygen ions on the surface of the composite was verified by measuring the change in intensity of CO2 signal upon exposure to urea solution using FTIR. Thus, the composite film acts as a low-cost non-enzymatic chemiresistive urea sensor with good sensitivity and reproducibility.