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

Abstract

photocatalyst. In this context, there are several reported works on Z-scheme-based semiconductors such as CdS/BiVO 4 , [2] BiVO 4 /CdS quantum dots (QDs), [3] CdS-WO 3 , [4] TiO 2 /CdS, [5] etc. Yet, the typical charge transfer process competes with the binary Z-scheme charge transfer and the photocatalytic performance is still unable to triumph the practical application, i.e., to conquer the concerns of sustainable energy and environment-related issues. Understandably then, scientists started focusing on the construction of ternary semiconductors with dual Z-scheme pathway for more effective charge separation. Many research groups have reported their findings in designing unidirectional double Z-scheme-based photocatalysts for water redox reactions and degradation of harmful pollutants. [6][7][8][9][10][11] Moreover, our group has reported photocatalytic reduction of Cr 6+ → Cr 3+ and water → H 2 over Cu-MoO 3 /g-C 3 N 4 hybrid nanocomposite. [6] Ternary Ag 2 CO 3 /CeO 2 /AgBr photocatalyst has been reported by Wen et al. with double Z-scheme configuration performing photodegradation of levofloxacin. [7] GO/Ag 2 CrO 4 /g-C 3 N 4 nanocomposite has been reported with superior photocatalytic performance toward refractory pollutant degradation [8] and AgBr@Bi 2 WO 6 /WO 3 for degrading rhodamine B. [9] A similar double Z-scheme photocatalytic system (Bi 2 S 3 /SnS 2 /Bi 2 O 3 ) has also been reported by Yu et al. for dye removal under sunlight irradiation. [10] ZnO/ZnS/g-C 3 N 4 ternary double Z-scheme heterojunction has been synthesized by Dong et al. for photocatalytic H 2 generation. [11] Despite accomplishments of certain stimulating achievements by these double Z-scheme photocatalysts, still improvements can be attained to scale up the practical application in the photocatalytic field. We report here a prototype novel confronting bidirectional double Z-schemebased UV-vis active photocatalyst with two single Z-scheme systems acting in opposite direction toward enhanced photocatalytic water oxidation reaction (WOR) and organic pollutants, i.e., tetracycline (TC) and methyl orange (MO). It consists of an oxygen evolution catalyst, i.e., BiVO 4 abbreviated as "B" (monoclinic clinobisvanite phase) composed of tetrahedron and octahedron of VO 4 and BiO 8 , respectively, with threefold coordinated O, fourfold coordinated V, and eightfold coordinated Bi. This phase of B collects distinct attention in WORs 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 allsolid-state coupled confronting Z-scheme (CCZ) system is synthesized by coprecipitation and hydrothermal method. This proof of concept comprises BiVO 4 (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 ...

Advances in layered double hydroxide-based ternary nanocomposites for photocatalysis of contaminants in water

“…The resulting mixture was aged for 8 h, followed by washing with ethyl alcohol and deionized water. Furthermore, Kandi et al [99] reported BiVO 4 /CdS/MgAl-LDH hybrid for the degradation of pollutant and water splitting under UV light irradiation. In their experiments, BiVO 4 was dispersed into mixed solution of Cd(NO 3 ) 2 •2H 2 O and thioglycolic acid (the molar ratio of 2:1).…”

Engineering Layered Double Hydroxide–Based Photocatalysts Toward Artificial Photosynthesis: State‐of‐the‐Art Progress and Prospects

“…f) Photocatalytic CCZ mechanism exists in H 2 and O 2 generation using BCL. [ 155 ] Copyright 2019, Wiley‐VCH.…”

“…This system allows BCL to have effective utilization of a wide range of light harvesting from 200 to 800 nm. [ 155 ] Thus, ternary heterostructure can be a compelling strategy to surmount a material's shortcoming to engineer a more robust photocatalyst.…”

Superactive NiFe-LDH/graphene nanocomposites as competent catalysts for water splitting reactions

“…5,139,140 Regarding photocatalytic performance, efficiency and stability, the development of more advanced, robust and extremely competent semiconductor photocatalysts for photocatalytic water splitting is still a challenge and more efforts are needed for the advancement of robust photocatalysts. [141][142][143] Heterogeneous photocatalytic water splitting is a green technology that introduces dispersed powdered photocatalysts and is more beneficial than the PEC technique because of its facile approach, sustainability, cost-effectiveness and external potential. [33][34][35][36][37]44 Generally, semiconductor photocatalysts used in photocatalytic water splitting depend on several necessities concerning the bandgap energy and electronic properties as follows.…”