Hierarchical sulfur-doped scaly carbon coupled with a cerium oxide nanoparticle-based electrochemical sensor for the sensitive determination of uric acid

Abstract

A cost-effective and environmentally friendly method has been proposed for synthesizing a nanomaterial composed of highly dispersed cerium oxide (CeO₂) nanoparticles anchored on sulfur-doped scaly carbon (CeO₂@S-SC). This nanomaterial was employed for the modification of a glassy carbon electrode, leading to the development of an electrochemical sensor with the capability of detecting uric acid (UA). The utilization of conductive sulfur-doped scaly carbon as interlayer spacers efficiently inhibited the aggregation of CeO₂ nanoparticles and formed a well-defined layered embedding structure. During the subsequent in situ hydrothermal process, CeO₂ was successfully decorated on the obtained sulfur-doped scaly carbon to further enhance its determination of UA due to its excellent redox activity, good dispersibility, and strong adsorption ability. Benefiting from the inherent advantages of its components and unique structural features, the obtained CeO₂@S-SC sensor exhibited a wide linear concentration range from 0.005 to 175 μM with a low limit of detection (3.1 nM). The buffer pH was found to be an important parameter for UA detection and a suitable pH value of 6.0 was selected in terms of high determination ability. Meanwhile, the fabricated sensor demonstrated exceptional levels of selectivity, stability (retained 95% of its initial value after 7 days), reproducibility (RSD = 4.5%), and repeatability (RSD = 3.6%). Additionally, the newly developed sensor was effectively utilized to detect UA in actual samples with favorable results (recoveries ranging from 92.9% to 105%).