Tunable photocatalytic Water-splitting by the Ferroelectric Switch in 2D AgBiP2Se6 Monolayer

Photocatalytic water-splitting is a promising technology to solve the energy crisis and provide renewable & clean energies. Recently, although numerous 2D materials have been proposed as the photocatalytic candidates, the strategies to effectively modulate photocatalytic reactions and conversion efficiency are still lacking. Herein, based on first principle calculations, we show that the photocatalytic activities and energy conversion efficiency can be well tuned by ferroelectric-paraelectric phase transition of AgBiP2Se6 monolayer. It is found that the AgBiP2Se6 monolayer has a higher potential and driving forces of photogenerated hole for water oxidation in ferroelectric phase, but the higher corresponding values of photogenerated electron for hydrogen reduction reaction in paraelectric phase. Besides, the solar-to-hydrogen energy conversion efficiency is also tunable with the phase transition, it is up to 10.04% at ferroelectric phase due to the better carrier utilization, but only 6.66% at paraelectri...