Porous carbon fabricated by a residue from Longquan lignite ethanolysis as an electrochemical sensor for simultaneous detection of hydroquinone and catechol in the presence of resorcinol

Catechol (CC), resorcinol (RS), and hydroquinone (HQ) are regarded as both important raw materials widely applied in chemical industry and highly toxic organic pollutants, so accurately detecting them is very necessary. In this work, Longquan lignite residue with low added value was fabricated as highly active porous carbons (PCs). The morphology, specific surface area (SSA), and electrocatalytic oxidation performance of the PCs prepared at different activated temperatures (600 ∼ 900 °C) were studied in detail. All PCs have different portions of micropores and mesoporous, and their SSAs can reach up to 3028 m2/g. Such well-developed microporous and mesoporous structures can provide abundant active sites to facilitate ion and electron transport, and thereby improving the electrocatalytic performance. Among them, the PC prepared at 800 °C shows the best detection performance. It can successfully detect HQ and CC simultaneously in the presence of RS, with detection limits of 0.15 and 0.81 µM for HQ, 0.09 and 0.53 µM for CC comparable to some graphene-based electrochemical sensors. Additionally, the constructed electrochemical sensor also displays a good reproducibility, stability, and anti-interference, which makes it a promising candidate material for monitoring phenolic compounds in actual water samples.