Molecularly Imprinted Photoelectrochemical Sensor for Ultrasensitive and Selective Detection of Hydroquinone Using 0D CdS Nanoparticle/3d Flower-Like ZnIn2S4 Microsphere Nanocomposite

A novel photoelectrochemical (PEC) sensor was developed for the ultra-sensitive and highly selective detection of hydroquinone (HQ), featuring a composite structure that combines 0D CdS nanoparticles with a 3D flower-like ZnIn2S4 microsphere. The sensor, termed rMIP/CdS/ZnIn2S4, employed molecularly imprinted polymers (MIPs) to achieve specific recognition of HQ. An p-phenylenediamine (pPD) polymer film was electrochemically polymerized onto the surface of the CdS/ZnIn2S4 composite-coated glassy carbon electrode (GCE). Through hydrogen bonding, HQ molecules were imprinted onto the polymer film. Subsequent elution removed these molecules, leaving behind specific recognition sites, enabling selective detection of HQ. The unique spatial structure and heterojunction properties of the 0D CdS nanoparticle/3D flower-like ZnIn2S4 composite, combined with molecular imprinting, significantly enhanced the photocurrent response and increased the selectivity and sensitivity for HQ detection. Under optimal conditions, the rMIP/CdS/ZnIn2S4 sensor demonstrated a low detection limit (0.7 nmol·L−1, S/N=3) over a wide linear range of 1–1200 nmol·L−1. The sensor was successfully applied to detect HQ in real water samples, showing promise for environmental pollution control applications.