High-Pressure Torsion for Highly-Strained and High-Entropy Photocatalysts

Abstract

Nowadays, the environmental crisis caused by using fossil fuels and CO2 emissions has become a universal concern in people’s lives. Photocatalysis is a promising clean technology to produce hydrogen fuel, convert harmful components such as CO2, and degrade pollutants like dyes in water. There are various strategies to improve the efficiency of photocatalysis so that it can be used instead of conventional methods, however, the low efficiency of the process has remained a big drawback. In recent years, high-pressure torsion (HPT), as a severe plastic deformation (SPD) method, has shown extremely high potential as an effective strategy to improve the activity of conventional photocatalysts and synthesize new and highly efficient photocatalysts. This method can successfully improve the activity by increasing the light absorbance, narrowing the bandgap, aligning the band structure, decreasing the electron–hole recombination, and accelerating the electron–hole separation by introducing large lattice strain, oxygen vacancies, nitrogen vacancies, high-pressure phases, heterojunctions, and high-entropy ceramics. This study reviews the recent findings on the improvement of the efficiency of photocatalysts by HPT processing and discusses the parameters that lead to these improvements.

Keywords

• photocatalysis
• water splitting
• oxygen vacancy
• nitrogen vacancy
• heterojunctions
• high-entropy alloys (heas)
• high-entropy ceramics