2D S-doped g-C₃N₄ and V₂CT_x nanocomposites for ultra-sensitive electrochemical sensing uric acid

Accurate and sensitive detection of uric acid (UA) is crucial, as abnormal UA levels are often indicative of various diseases. This work introduces a straightforward electrochemical sensor utilizing a two-dimensional (2D) nanocomposite of S-doped g-C₃N₄ (SCN) and V₂CT_x MXene (SCN/V₂C), which was prepared via ball milling followed by calcination. The SCN/V₂C nanocomposite demonstrates superior conductivity and a reduced band gap relative to pure g-C₃N₄, leading to improved electrochemical performance for UA detection. Differential pulse voltammetry (DPV) measurements revealed a limit of detection (LOD) of 1 μM for UA and a linear response range spanning from 3 μM to 1 mM. Furthermore, experimental results confirmed the excellent stability of the SCN/V₂C nanocomposite. Density functional theory (DFT) calculations revealed that SCN/V₂C acts as a powerful electron donor, while UA functions as an efficient electron acceptor. The electron transfer between SCN/V₂C and UA is significantly greater than that with other common interfering biological molecules, leading to the highest adsorption energy of UA on the SCN/V₂C surface. This strong interaction accounts for the sensor’s exceptional selectivity. This newly developed sensor provides a straightforward and highly sensitive approach for the electrochemical detection of trace levels of UA in real biological samples.