Construction of a Ce‐UiO‐66/MCo₂O₄ Heterojunction for Photocatalytic Cr(VI) Detoxification Through a p‐n Junction Formation Mechanism

Abstract

Heterojunction engineering in catalyst structures is a promising approach to solve some restrictions in photocatalyst design, such as a narrow photoabsorption range and rapid recombination of photogenerated charge carriers. In this work, MCo2O4 (M=Mn, Zn, Fe) was synthesized using a template method. The porous MCo2O4 was composited by Ce‐UiO‐66 to form a heterojunction structure. The resultant material Ce‐UiO‐66/MCo2O4 had a hierarchically porous architecture and was used as a photocatalyst for Cr(VI) reduction. The coupling of Ce‐UiO‐66 and MCo2O4 resulted in a p‐n junction mechanism for charge carrier transfer. The Ce‐UiO‐66/MCo2O4 heterojunctions exhibited high Cr(VI) reduction ability under visible light irradiation over 120 min. The highest Cr(VI) photoreduction rate of the heterojunction is 14 times that of Ce‐UiO‐66. The binary heterojunction maintains high photoreduction efficiency (100 %) of Cr(VI) after four cycling tests showing excellent photocatalytic stability.

Enhancing Photocatalytic Cr(VI) Detoxification and N2 Fixation through Construction of a Z-Scheme Heterojunction via Partial Derivatization of BiOBr on the MOF-808/Bi-BDC Composite

“…Figure d shows that when the pH level increases, the reaction rate slows down due to the conversion of HCrO 4 – to more negative species like CrO 4 2– and Cr 2 O 7 2– . This transformation hinders the attraction of anionic chromate to the surface, leading to low catalytic efficiency caused by repulsion. , …”

A comprehensive study about functionalization and de-functionalization of MOF-808 as a defect-engineered Zr-MOFs for selective catalytic oxidation

“…Recently, MOFs have received more and more attention due to their potential applications from researchers [ [1] , [2] , [3] ]. MOFs can be widely used as catalysts in the oxidation of sulfide due to their unique advantages (including a high surface area, high porosity, abundant active Lewis/Brønsted acidic or basic sites, and controllable pore size) [ [4] , [5] , [6] ].…”