X-ray photoelectron spectroscopy determination of the Ce(III)/Ce(IV) ratio in cerium compounds

Developing environmental and cost-effective antifouling technologies is essential to solve serious biofouling problems. Recently, enzyme mimics and halogenating enzymes have caught progressively attention as valuable tools to combat biofilm formation. In this work, the core-shell structure of CeO2@C, as one effective haloperoxidase-like enzyme mimics, was successfully synthesized using the carbon sphere as template through a simple coprecipitation method. Through the UV–vis absorption spectra and kinetic measurements, the CeO2@C displays intrinsic haloperoxidase-like activity via catalyzing the bromination of organic signaling compounds. Meanwhile, the prepared CeO2@C catalyst process high catalytic stability and recyclability, corresponding to a well catalytic performance repeatability after refresh of raw substrates (at least 10 times). The antibactrial property of CeO2@C as haloperoxidase mimicry is evaluated by immersing titanium plate/CeO2@C modified titanium plates into bacterial suspensions with different conditions for 4 h at 37 °C. It can catalyze the oxidation of Br− with H2O2 to the corresponding hypobromous acid (HBrO), which exhibits strong antibacterial activity against Gram-negative (Escherichia coli), Gram-positive (Staphylococcus aureus) bacteria and typical marine (Pseudomonas aeruginosa) bacteria. This study introduces a stable, non-poisonous and inexpensive biomimetic material for antibacterial, antifouling and disinfection applications based on novel sustainable and conservation methods.