Excessive CO2 emission from fossil fuel usage has resulted in global warming
and environmental crises. To solve this problem, photocatalytic conversion of
CO2 to CO or useful components is a new strategy that has received significant
attention. The main challenge in this regard is exploring photocatalysts with
high activity for CO2 photoreduction. Severe plastic deformation (SPD) through
the high-pressure torsion (HPT) process has been effectively used in recent
years to develop novel active catalysts for CO2 conversion. These active
photocatalysts have been designed based on four main strategies (i) oxygen
vacancy and strain engineering, (ii) stabilization of high-pressure phases,
(iii) synthesis of defective high-entropy oxides, and (iv) synthesis of
low-bandgap high-entropy oxynitrides. These strategies can enhance the
photocatalytic efficiency compared to conventional and benchmark photocatalysts
by improving CO2 adsorption, increasing light absorbance, aligning the band
structure, narrowing the bandgap, accelerating the charge carrier migration,
suppressing the recombination rate of electrons and holes, and providing active
sites for photocatalytic reactions. This article reviews recent progress in the
application of SPD to develop functional ceramics for photocatalytic CO2
conversion