Longquan lignite-derived hierarchical porous carbon electrochemical sensor for simultaneous detection of hazardous catechol and hydroquinone in environmental water samples

Catechol (CC) and hydroquinone (HQ) featured with toxicity and wide application are regarded as organic pollutant in wastewater, so the detection of CC and HQ is very important. Besides, direct use of low-rank lignite for combustion is not only wasteful, but also leads to increased greenhouse gas production. Hence, its efficient and clean utilization accords with the process of social development and the concept of carbon neutrality. Based on the above two problems, a method of killing two birds with one stone was proposed to solve the clean utilization of lignite and be used to detect CC and HQ. Herein, a series of porous carbons derived from Longquan lignite with well-developed microporous and mesoporous structure were fabricated by pyrolysis, carbonization, and activation under various activation temperatures (600–900 °C). This combination of microporous and mesoporous structures can increase the surface area (3113 m2/g) and the active site of the porous carbon, improve its electrical conductivity and electron transport efficiency, and make it as a substrate for constructing electrochemical sensor (ECS) with excellent electrocatalytic activity, and successfully be applied in simultaneous detection of CC and HQ. Compared with some reported results, the prepared ECS exhibits satisfactory electrochemical sensing performance with wider linear concentration range and lower detection limits of 0.16 μM for CC and 0.16 μM for HQ, which is comparable to graphene-based sensors. Furthermore, the ECS possesses good stability, reproducibility, selectivity, and anti-interference, and shows practical applicability in environmental water samples.