Z-Scheme ZnM-LDHs/g-C₃N₄ (M = Al, Cr) Photocatalysts: Their Desulfurization Performance and Mechanism for Model Oil with Air

Abstract

Photocatalytic oxidation desulfurization is presently challenged with low quantum efficiency and high combination rate of electron–hole, and the key to success is to design efficient multicomponent composite photocatalysts. This work successfully synthesized Z-scheme photocatalysts ZnM-LDHs/g-C3N4 (M = Al, Cr) by the electrostatic self-assembly, analyzed their work mechanism through various characterization technique such as XPS, PL, TRPL, and ESR, explored the activity enhanced mechanism, and revealed the reason of their catalytic activity difference. Photocatalytic oxidation/extraction desulfurization of ZnAl-LDHs/g-C3N4 and ZnCr-LDHs/g-C3N4 can achieve 99.8 and 96.6%, respectively, in 3 h for model oil. The results are instructive for the structure design and study of efficient photocatalysts in desulfurization.

Boosting Photocatalytic Activity Using Carbon Nitride Based 2D/2D van der Waals Heterojunctions

“…have been developed to convert the LDHs into 2D sheets through delamination. − These 2D sheets, due to high surface area, rich active sites, and excellent visible absorption, can induce various photochemical reactions. The face-to-face interaction of LDHs with carbon nitride to make the vdW heterojunction has been found to boost photocatalytic performance. − The potential of such a combination has already been traversed by Song et al Within a short span, a few more reports have emerged on the 2D/2D heterojunction/close contact of carbon nitrides and LDHs. − …”

A current overview of the oxidative desulfurization of fuels utilizing heat and solar light: from materials design to catalysis for clean energy

“…248 Huang et al hybridized ZnAl-and ZnCr-LDH with g-C 3 N 4 nanosheets through an electrostatic selfassembly approach to establish a Z-scheme heterojunction to improve the efficiency in light-driven ODS. 249 The Z-scheme heterojunction recombined excited electrons from LDH and holes from g-C 3 N 4 , preserving the free reactive electrons and holes in the CB of g-C 3 N 4 and the VB of LDH, respectively, for redox reactions, which was greatly conducive to the ODS reaction rate (Fig. 22i).…”

Photocatalytic Air Purification Using Functional Polymeric Carbon Nitrides

“…successfully synthesized direct Z‐scheme photocatalysts of ZnM‐LDHs/PCN (M = Al, Cr) by electrostatic self‐assembly (Figure 12D ). [ 305 ] Photocatalytic desulfurization of ZnAl‐LDHs/PCN and ZnCr‐LDHs/PCN could reach above 95%, which was primarily ascribed to the improved carrier transfer, the suppressed electron–hole recombination, and the improved redox potential. A triplex CuO–ZnO/PCN dual Z‐scheme heterojunction was achieved via a multistep ultrasound‐assisted hydrothermal procedure, showing a 99.1% desulfurization rate and excellent stability under visible‐light‐irradiation.…”

“…D) Z-scheme heterostructure of the photocatalytic oxidation of ZnM-LDHs/PCN (M = Al, Cr). Reproduced with permission [305]. Copyright 2020, American Chemical Society.…”