Photoelectrochemical sensor for hypochlorous acid detection based on the MWNTs doped PEDOT loaded with BP5 functionalized gold nanoparticles

Hypochlorous acid concentration anomaly may cause many serious diseases, so the development method to detect HClO high sensitivity and selectivity is of great significance in clinical diagnosis. Among many methods for detecting HClO, photoelectric chemical sensor has the advantages of high sensitivity and strong anti-interference ability, and has been widely used in the field of detecting HClO. Herein, a simple and specific photoelectrochemical sensor was constructed using A1/B1-type pillar[5]arene functionalized Au NPs and multi-walled carbon nanotube-polythiophene composites for the detection of hypochlorous acid. This approach was based on a sulfhydryl-borate ester modified A1/B1 type pillar[5]arene (BP5) as the main body, hypochlorous acid (HClO) as the guest, multi-walled carbon nanotube (MWNTs) conducting polymers doped with poly(3,4-ethylenedioxythiophene) (PEDOT) as the transport bridge and signal amplifier, as well as spherical gold nanoparticles act as the signal reporter. Specifically, the photoelectrochemical efficiency was further enhanced by the localized surface plasmon resonance effect (LSPR) of gold nanoparticles (Au NPs) and the host-guest complexation between BP5 and HClO. The large specific surface area of MWNTs doped with PEDOT significantly enhanced the electrical conductivity and chemical stability of PEDOT, facilitating accelerated electron transfer and mitigating the recombination of the photogenerated electron-hole pairs. Benefiting from the combination of Au NPs, BP5, MWNTs and PEDOT, the sensor exhibited excellent sensitivity with detection range of 0.5–340 μM and a detection limit of 0.17 μM, and distinguished selectivity against 6 interfering substances. Due to the adsorption and removal effects of pillar[5]arenes on heavy metal ions and pollutants in water, as well as their effective catalytic performance, we anticipate that this composite material also has great potential in photoelectrochemical detection, catalysis, and adsorption.