Paper-based molecularly imprinted electrochemical sensor integrated with Pt single atom decorated porous hollow carbon polyhedrons for enhanced phenolic pollutants monitoring in wastewaters

We present a disposable paper-based molecularly imprinted electrochemical sensor for highly sensitive and selective monitoring of phenolic pollutants. The sensor features a fully integrated three-electrode array fabricated through an eco-friendly vacuum filtration method, which utilizes single-walled carbon nanotube-based substrates to provide excellent conductivity, large surface area, and low-cost electrode platforms. These substrates enable effective deposition of hollow-structured zeolitic imidazolate framework-8-derived N-doped carbon polyhedrons supporting Pt single-atom catalysts (Pt-N-C) synthesized via high-temperature calcination. Subsequent electropolymerization of a molecularly imprinted polymer (MIP) on the electrode surface was achieved using 3,4-ethylenedioxythiophene and pyrrole as dual functional monomers. Comprehensive characterization demonstrates that the Pt-N-C architecture exhibits abundant atomic Pt catalytic sites, nitrogen-decorated hierarchical porosity, and maximized electrochemical accessibility, collectively contributing to exceptional detection sensitivity for multiple phenolic compounds including 2-chloro-4-methoxyphenol, 4-bromo-2-methoxyphenol, 4-aminophenol, and 4-nitrophenol. Concurrently, the MIP layer demonstrates rapid binding kinetics and high molecular recognition capacity, significantly enhancing selective identification capabilities. The developed sensor successfully achieves direct quantification of these phenolic contaminants in unprocessed complex wastewater samples without requiring pretreatment procedures.