Let's collaborate! MCo₂O₄ (M=Mn, Zn, Fe) was synthesized and combined with Ce-UiO-66 to create a heterojunction structure for use as a photocatalyst for chromium(VI) reduction. The resulting Ce-UiO-66/MCo₂O₄ heterojunctions exhibited high Cr(VI) reduction under visible light irradiation and maintained high photoreduction efficiency even after four cycling tests, demonstrating excellent photocatalytic stability.

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.