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Highlights • Graphene oxide (GO) hydrogel was induced by synergistic effect of pyrrole and Co2+. • S and N are doped in graphene framework with doping/reducing agent of L -Cysteine. • 3D-sturctrue are obtained via evaporation induced drying without freeze-drying. • The 3D S/N-co-doped graphene show enhanced response for hydroquinone and catechol. Abstract Herein, a three-dimensional self-assembled hydrogel of graphene oxide sheets induced by pyrrole and Co2+ is described. Controlled shrinkage and sulfur/nitrogen co-doping occurred in the subsequent hydrothermal process. The obtained 3D sulfur/nitrogen co-doped graphene was further dried through direct evaporation, without freeze-drying. SEM images demonstrated a surface 3D structure with high roughness and composed of interconnected sheets. This newly fabricated 3D sulfur/nitrogen co-doped graphene was used in the simultaneous detection of catechol and hydroquinone with low detection limits of 0.28 and 0.15 μM, respectively. [ABSTRACT FROM AUTHOR]

Abstract: A novel poly(3,4-ethylenedioxy-thiophene) (PEDOT)/graphene oxide (GO) hybrid film was directly electrodeposited on a glassy carbon electrode. The SEM and TEM images of the as-obtained film revealed that PEDOT grew well on the surface of GO sheets with high affinity. The chemical structure of the composite was characterized by FT-IR, and the result conformed the formation of PEDOT doped by GO, leading to the enhanced electrochemical performance of the modified electrode. The composite modified electrode was utilized as an electrochemical sensor for the simultaneous detection of hydroquinone (HQ) and catechol (CT). It showed well electrocatalytic activity toward the redox of HQ and CT. Under the optimized condition, the response peak currents of the modified electrodes were linear over ranges from 2.5 to 200μM for HQ and from 2 to 400μM for CT. The sensor also exhibited good sensitivity with the detection limit of 1.6μM for both HQ and CT, and good stability. This study provides a new kind of composite modified electrode for electrochemical sensors. [Copyright &y& Elsevier]