Indirect Z-Scheme BiOI/g-C₃N₄ Photocatalysts with Enhanced Photoreduction CO₂ Activity under Visible Light Irradiation

Abstract

Rational design and construction of Z-scheme photocatalysts has received much attention in the field of CO2 reduction because of its great potential to solve the current energy and environmental crises. In this study, a series of Z-scheme BiOI/g-C3N4 photocatalysts are synthesized and their photocatalytic performance for CO2 reduction to produce CO, H2 and/or CH4 is evaluated under visible light irradiation (λ > 400 nm). The results show that the as-synthesized composites exhibit more highly efficient photocatalytic activity than pure g-C3N4 and BiOI and that the product yields change remarkably depending on the reaction conditions such as irradiation light wavelength. Emphasis is placed on identifying how the charge transfers across the heterojunctions and an indirect Z-scheme charge transfer mechanism is verified by detecting the intermediate I3(-) ions. The reaction mechanism is further proposed based on the detection of the intermediate (•)OH and H2O2. This work may be useful for rationally designing of new types of Z-scheme photocatalyst and provide some illuminating insights into the Z-scheme transfer mechanism.

g‐C3N4‐Based Heterostructured Photocatalysts

“…Many gC 3 N 4 based systems showed enhanced separation efficiency of photogenerated charge carriers, for example, by coupling gC 3 N 4 with a second semiconductor, such as TiO 2 , [272,279] Ag 3 PO 4 , [280] In 2 O 3 , [98] ZnO, [171,281] LaPO 4 , [282] Bi 2 WO 6 , [274] CeO 2 , [283] WO 3 , [186] AgX (X = Cl and Br), [284] NaNbO 3 , [285] BiOI, [176] CdS, [286] and CdMoO 4 . Many gC 3 N 4 based systems showed enhanced separation efficiency of photogenerated charge carriers, for example, by coupling gC 3 N 4 with a second semiconductor, such as TiO 2 , [272,279] Ag 3 PO 4 , [280] In 2 O 3 , [98] ZnO, [171,281] LaPO 4 , [282] Bi 2 WO 6 , [274] CeO 2 , [283] WO 3 , [186] AgX (X = Cl and Br), [284] NaNbO 3 , [285] BiOI, [176] CdS, [286] and CdMoO 4 .…”

Bio-inspired Z-scheme g-C3N4/Ag2CrO4 for efficient visible-light photocatalytic hydrogen generation

“…44 synthetized a ternary composite photocatalyst g-C 3 N 4 /Ag 3 PO 4 /Ag 2 MoO 4 for water splitting. BiOCl and BiOI were also compounded with g-C 3 N 4 as high efficiency photocatalysts 43,47 . As a promising catalyst, Bi 2 WO 6 was also combined with g-C 3 N 4 to form a Z-scheme catalytic system 48 .…”

Photocatalytic reduction of CO 2 with H 2 O over graphene oxide-supported oxygen-rich TiO 2 hybrid photocatalyst under visible light irradiation: Process and kinetic studies

“…Therefore, the ability to harness the power of CO 2 on a large scale and integrate it back into the utilization cycle as a sustainable form of energy production is highly desirable. Among the various renewable projects to date, the photocatalytic reduction of CO 2 into energy-bearing products has garnered interdisciplinary research attention to mitigate the evergrowing CO 2 concentration and to meet the long-term worldwide energy demands without utilizing further CO 2 -generating power resources [6][7][8][9][10][11][12][13][14][15]. In this context, photocatalysis, a wellorchestrated mimic of natural photosynthesis, for direct conversion of solar energy to chemical energy, presents an opportunity to kill these two birds with one stone [16][17][18][19].…”