An “On‐Site Transformation” Strategy for Electrochemical Formation of TiO₂ Nanoparticles/Ti₃C₂Tx MXene/Reduced Graphene Oxide Heterojunction Electrode Controllably toward Ultrasensitive Detection of Uric Acid

Ascribing to the abundance of Ti element, exceptional electrical conductivity, and electrocatalytic performance, titanium carbide MXene (Ti 3 C 2 T x , MX) is considered as an ideal conductive matrix and employed for in situ preparation of promising TiO 2 NPs@MX/reduced graphene oxide (rGO) heterojunction electrodes for uric acid (UA) detection. However, the incapability of achieving the controllable growth and synthesis of TiO 2 nanoparticles (NPs) on MX nanosheets is a bottleneck in fabricating optimal and controllable TiO 2 NPs@MX hybrid. Herein, an “on‐site transformation strategy” is developed to synthetize TiO 2 NPs@MX/rGO heterojunction platform controllably by in situ electrochemical oxidizing MX nanosheets at various treatment times. The proposed approach allows for the greater operability to controllably grow and synthetize TiO 2 NPs on the surface of MX nanosheets. The heterojunction electrodes present a linear voltammetric response toward UA in the concentration range of 0.003–0.3 and 0.3–300 μ m and a low detection limit of 0.78 n m ( S / N = 3). Additionally, a handheld electrochemical system with a smartphone readout is developed for point‐of‐care health monitoring, enabling fast, precise, and specific recognition of UA in real urine samples. The study provides a facile and controllable approach to fabricate TiO 2 NPs@MX/rGO heterojunction platform for future use in other biomolecules' detection.