Oxidized carboxymethyl cellulose/polyaniline-based hybrid nanocomposite for sensitive detection of environmentally hazardous nitrophenol in real samples

•Highly effective hybrid Ag@Pani/O-CMC-nanocomposite-based electrochemical sensor.•Impregnation of Ag@Pani to O-CMC matrix promotes sensing performance.•Trace detection of 4-Nitrophenol with LOD of 0.58 nM.•Remarkably sensitivity of 2.48 µA nM−1 cm−2 with high stability and great selectivity.