Free-electrodeposited anodic stripping voltammetry sensing of Cu(II) based on Ti₃C₂T_x MXene/carbon black

A proof-of-principle concept for free-electrodeposited anodic stripping voltammetry (ASV) sensing of Cu²⁺ is proposed by using Ti₃C₂T_x MXene/carbon black (Ti₃C₂T_x@CB) nanohybrids as electrode materials. Owing to the high adsorption and reduction capability of Ti₃C₂T_x towards Cu²⁺, Ti₃C₂T_x MXene enables Cu²⁺ to be immobilized and self-reduced directly to form Cu⁰ on the Ti₃C₂T_x@CB electrode surface. As a result an oxidation peak current appears from the re-oxidation of Cu⁰ via differential pulse voltammetry. Carbon black (CB) was introduced to prevent Ti₃C₂T_x Mxene aggregation and improve the related electron transfer as well as enhance their surface area. After optimizing various conditions, a considerable low limit of detection (4.6 nM) and a wide linear range (0.01-15.0 μM) for Cu²⁺ were achieved at the working potential from - 0.3 V to 0.0 V (vs SCE). Relative standard deviation (RSD) of eight individual Ti₃C₂T_x@CB electrodes is 3.72%, and the recoveries from tap water sample and lake water sample were in the ranges of 97.0-108% and 104-107%, respectively.