Construction of nanosensor based on cobalt phosphate-doped biochar for derivative voltammetric analysis of hydroquinone in environmental samples

A nanosensing platform was designed based on environmentally friendly cobalt phosphate-doped biochar (CoCPBC) derived from bamboo leaves for derivative voltammetric determination of hydroquinone  (HQ) in water and soil samples. Highly ambient-stable CoCPBC is prepared by hydrothermal synthesis containing cobalt nitrate, phosphoric acid (H 3 PO 4 ), cetyltrimethylammonium ammonium bromide (CTAB), and bamboo leaves. Benefiting from the high effective area, the CoCPBC displays more active sites for HQ recognition and simultaneously improving the conductivity of biochar. The CoCPBC electrode shows excellent stability with retaining 99.34% of its initial current after 100   cyclic voltammetric scans. The CoCPBC nanosensor, enhanced by signal amplification, enables the determination of HQ in the concentration range 0.1–500 μM, with a detection limit of 0.052 μM. It exhibits high selectivity and excellent practicability, utilizing differential pulse voltammetry and first derivative voltammetry for detection. This work will provide an innovative method for the preparation of functional biochars from agroforestry wastes and their applications in the development of electrochemical nanosensing platforms. Highlights 1. A green and sustainable method to convert forestry waste into biochar using bamboo leaves as carbon source; 2. The acid activation and surfactant pore-expanding increase specific surface area and electrochemically-active sites; 3. Co-doping enhanced the conductivity and electrocatalytic activity of biochar. 4. Realization of derivative voltammetric determination of hydroquinone. Graphical