Facile synthesis of Ti3C2Tx@gold nanoparticle-arginine and serine-functionalized graphene quantum dot aerogel for electrochemical detection of chloramphenicol

Abstract

Ti₃C₂T_x has been extensively used as a promising sensing material for the construction of electrochemical sensors because of its excellent conductivity, surface area and mechanical properties, but the two-dimensional structure and poor catalytic activity of Ti₃C₂T_x limit the improvement of its analytical behavior. This paper reports a facile method for the synthesis of a Ti₃C₂T_x@gold nanoparticle-arginine- and serine-functionalized graphene quantum dot aerogel (Ti₃C₂T_x@Au–AS-GQD). AS-GQD was prepared by heating a mixture of citric acid, arginine and serine. The formed AS-GQD was used to reduce chloroauric acid to produce gold nanoparticles. The gold nanoparticles protonated with hydrochloric acid were dropped into a Ti₃C₂T_x aqueous solution to form Ti₃C₂T_x@Au–AS-GQD. The Ti₃C₂T_x@Au–AS-GQD shows one three-dimensional structure. Small gold nanoparticles were uniformly dispersed on the Ti₃C₂T_x sheets. The introduction of AS-GQD resulted in the formation of Schottky heterojunction and enhanced the catalytic activity. The electrochemical sensor fabricated with Ti₃C₂T_x@Au–AS-GQD exhibited high sensitivity, selectivity and repeatability in the electrochemical detection of chloramphenicol. The differential pulse voltammetric current at −0.6 V linearly increased with the increase in chloramphenicol within 0.003–100 μM, exhibiting a detection limit of 0.0012 μM (S/N = 3). The sensitivity of our sensor toward chloramphenicol was better than those of other electrochemical sensors. This study also paves an avenue for the construction of Ti₃C₂T_x composites with excellent catalytic activity in sensing, catalysis and energy storage and conversion.