In this work, a label-free nonenzymatic
photoelectrochemical (PEC)
sensor is successfully developed for the detection of a typical pollutant,
microcystin-LR (MC-LR), based on a visible-light-responsive alloy
oxide, with highly ordered and vertically aligned Ti–Fe–O
nanotubes (NTs) as substrates. Ti–Fe–O NTs consisting
mainly of TiO2 and atomically doped Fe2O3 are in situ prepared on a Ti–Fe alloy
by electrochemical anodic oxidation. Using a simple electrochemical
deposition technique, reduced graphene oxide (RGO) could be grown
onto Ti–Fe–O NTs, exhibiting significant bifunctions.
It not only provides an ideal microenvironment for functionalization
of molecularly imprinted polymers (MIPs) on the surface but also serves
as the PEC signal amplification element because of its outstanding
conductivity for photons and electrons. The designed MIP/RGO/Ti–Fe–O
NT PEC sensor exhibits high sensitivity toward MC-LR with a limit
of detection as low as 10 pM. High selectivity toward MC-LR is also
proven for the sensor. A promising detection platform not only for
MC-LR but also for other pollutants has therefore been provided.