New trends on photoelectrocatalysis (PEC): nanomaterials, wastewater treatment and hydrogen generation

The need for novel water treatment technologies has been
recently recognised as concerning contaminants (organics and
pathogens) are resilient to standard technologies. Advanced
oxidation processes degrade organics and inactivate
microorganisms via generated reactive oxygen species (ROS).
Among them, heterogeneous photocatalysis may have
reduced efficiency due to, fast electron-hole pair
recombination in the photoexcited semiconductor and reduced
effective surface area of immobilised photocatalysts. To
overcome these, the process can be electrically assisted by
using an external bias, an electrically conductive support for the
photocatalyst connected to a counter electrode, this is known
as photoelectrocatalysis (PEC). Compared to photocatalysis,
PEC increases the efficiency of the generation of ROS due to
the prevention of charge recombination between
photogenerated electron-hole pairs thanks the electrical bias
applied. This review presents recent trends, challenges,
nanomaterials and different water applications of PEC
(degradation of organic pollutants, disinfection and generation
of hydrogen from wastewater).