Rational Design of a Coupled Confronting Z-Scheme System Toward Photocatalytic Refractory Pollutant Degradation and Water Splitting Reaction

Fabricating competent nanoarchitecture photocatalytic systems with desired band edge potential is crucial for effective charge separation that manifolds photocatalytic action. Here, a prototype pristine rational design of all-solid-state coupled confronting Z-scheme (CCZ) system is synthesized by coprecipitation and hydrothermal method. This proof of concept comprises BiVO4 (B) and MgAl layered double hydroxide (L) as photosystem II (PS-II) whereas CdS quantum dots (QDs, C) as photosystem I (PS-I). CdS QDs trigger H-2 production that subsequently boosts O-2 production at PS-II. Furthermore, this rare CCZ system shows tremendous performance in methyl orange (MO) and tetracycline (TC) degradation. The prepared Z-scheme photocatalysts are capable of generating 17 350 and 33 000 mu mol h(-1) g(-1) of O-2 and H-2 under UV light irradiation, which correspond to apparent conversion efficiency of 7.22% and 13.73%, respectively. The catalyst is able to degrade, respectively, 92% and 51% of 20 mg L-1 TC and MO in 1 h. Maximum accessibility of charge carriers at final charge-separated state appears to be the basic cause in driving the photocatalytic activity efficiently. In spite of their various morphologies, synergistic interaction among C, B, and L can be effectively utilized to trigger various photocatalytic reactions.