Utilization of the internal electric field in semiconductor photocatalysis: A short review

Utilization of the internal electric field in semiconductor photocatalysis: A short review

Photocatalysis denotes as an environmental friendly chemical transformation technique. The rate ofphotoinduced electron–hole recombination is one of the difficulties encountered in semiconductorphotocatalysis.Differentalternative systemswere suggestedtoovercomethisproblemandthereby improvethe efficiency of the photocatalyst. Extensively investigated methods were not effective to achieve therequired efficiencyof the catalyst,becausethecatalystcharge carrierseparation is poor. Among theexploredmethods, the electron–hole separation using built-in electricfield attracts considerable attention as a newconcept. A spontaneous potential from the ferroelectric material strongly minimizes the number ofphotoinduced electron–hole recombination. On the other hand, the spontaneous potential wascompensated by the external and internal charge and to alternate the electricfield, thermal, mechanicaland electricfield were applied as an external force. The external force was exerted by different methods,including passage of ultrasound waves,fluid eddy,flowing water, mechanical distribution and changing thetemperature. Preliminary work has been carried out using semiconductor-Ferroelectric nanohybridpiezophotocatalyst in environmental remediation for the removal of an organic color and non-coloredpollutants. Later, the application was extended to hydrogen production from water splitting andantibacterial material development. Furthermore, the light free catalysts such as piezocatalyst, dark catalystand vibration catalyst are also examined for last decades. In this review, we summarize the work carried outby the internal electricfield induced photocatalyst electron–hole separation (Piezo photocatalyst) andtemperature triggered catalyst (Pyrocatalyst). Light free or vibration catalyst (piezocatalyst) work alsobrieflycoveredinthisreview. Overall,themanuscriptwasdiscussedinfourcategoriesofmaterials,includingBaTiO3, ZnO, other ABO3 structures and two-dimensional nanostructures including MoS2, WS2, MoSe2. Thechallenges encountered, and the present and future scope of the work is also discussed in this review.

Photocatalysis denotes as an environmental friendly chemical transformation technique. The rate ofphotoinduced electron–hole recombination is one of the difficulties encountered in semiconductorphotocatalysis.Differentalternative systemswere suggestedtoovercomethisproblemandthereby improvethe efficiency of the photocatalyst. Extensively investigated methods were not effective to achieve therequired efficiencyof the catalyst,becausethecatalystcharge carrierseparation is poor. Among theexploredmethods, the electron–hole separation using built-in electricfield attracts considerable attention as a newconcept. A spontaneous potential from the ferroelectric material strongly minimizes the number ofphotoinduced electron–hole recombination. On the other hand, the spontaneous potential wascompensated by the external and internal charge and to alternate the electricfield, thermal, mechanicaland electricfield were applied as an external force. The external force was exerted by different methods,including passage of ultrasound waves,fluid eddy,flowing water, mechanical distribution and changing thetemperature. Preliminary work has been carried out using semiconductor-Ferroelectric nanohybridpiezophotocatalyst in environmental remediation for the removal of an organic color and non-coloredpollutants. Later, the application was extended to hydrogen production from water splitting andantibacterial material development. Furthermore, the light free catalysts such as piezocatalyst, dark catalystand vibration catalyst are also examined for last decades. In this review, we summarize the work carried outby the internal electricfield induced photocatalyst electron–hole separation (Piezo photocatalyst) andtemperature triggered catalyst (Pyrocatalyst). Light free or vibration catalyst (piezocatalyst) work alsobrieflycoveredinthisreview. Overall,themanuscriptwasdiscussedinfourcategoriesofmaterials,includingBaTiO3, ZnO, other ABO3 structures and two-dimensional nanostructures including MoS2, WS2, MoSe2. Thechallenges encountered, and the present and future scope of the work is also discussed in this review.