CdS/Ti₃C₂ heterostructure–based photoelectrochemical platform for sensitive and selective detection of trace amount of Cu²⁺

Photoelectrochemical (PEC) detection as a potential development strategy for Cu²⁺ ion sensor has arisen extensive attention. Herein, CdS/Ti₃C₂ heterostructure was synthesized by electrostatically driven assembly and hydrothermal method. On the basis of a CdS/Ti₃C₂ heterostructure, a novel anodic PEC sensing platform was constructed for highly sensitive detection of trace amount of Cu²⁺. Carrier transport at the interface of CdS/Ti₃C₂ heterostructure was tremendously improved, due to the generation of effective Schottky junctions. Under visible light irradiation, the CdS/Ti₃C₂ heterostructure-modified PEC platform exhibits great anode photocurrent signal, and the formation of CuₓS reduces the PEC response with the presence of Cu²⁺ as a representative analyte. Thus, the linear response of Cu²⁺ ranges from 0.1 nM to 10 µM and the limits of detection (LOD, 0.05 nM) are obtained, which is lower than that of WHO's Guidelines for Drinking-water Quality (30 μM). This idea of component reconstitution provides a new paradigm for the design of advanced PEC sensors.