Superior electrochemical performance of doped porous graphene electrode for supercapacitor and paraquat detection

Abstract

The pursuit of high-performance materials for energy storage and sensing applications has fueled significant advancements in engineering doped graphene nanomaterials, which offer remarkable properties such as high surface area, efficient charge transfer, and stability. This study explores the applications of porous graphene codoped with boron and nitrogen (PBN-Gr) for supercapacitors and electrochemical sensing. Employing a facile photothermal synthesis method, PBN-Gr was produced. For electrochemical energy storage, PBN-Gr demonstrated a high specific capacitance of 3.29 mF cm-2 at a current density of 50.94 mu A cm-2 in 1 M Na2SO4, attributed to its porous structure. The electrode exhibited exceptional stability, retaining 95 % of its initial capacitance after 15,000 cycles. A Ragone plot revealed an energy density of 0.46 mW h cm-2 and power density of 3.54 mu W cm-2, demonstrating strong potential for high-performance supercapacitors. In electrochemical sensing, PBN-Gr proved highly effective for detecting paraquat (PQ), with a detection limit of 0.038 mu M, well below the WHO permissible limit and sensitivity of 4.39 mu A/mu M in 0.1 M phosphate buffer at pH 6.0 using square wave anodic stripping voltammetry. The linear detection range extended from 1 mu M to 9 mu M PQ. The electrodes also showed excellent performance in real soil samples, with a detection limit of 0.15 mu M. With the combination of superior energy storage and sensing capabilities, PBN-Gr is a promising candidate for dual applications in supercapacitors and electrochemical detection of PQ.