Stable Black Phosphorus Encapsulation in Porous Mesh-like UiO-66 Promoted Charge Transfer for Photocatalytic Oxidation of Toluene and o-Dichlorobenzene: Performance, Degradation Pathway, and Mechanism

This work presents a new strategy to enhance the charge transfer from Zr atoms in UiO-66 to black phosphorus (BP) via an atomic-level charge-transfer channel provided by Zr–P bonds for photocatalytic degradation of toluene and o-dichlorobenzene. The formation of Zr–P bonds is the key to covering BP with the UiO-66 encapsulation layer and improving the charge-transfer capability of BP–UiO, which is also verified by a series of characterization and theoretical calculations. The hydrophilic porous mesh-like UiO-66 encapsulation layer endows BP–UiO with enhanced visible-light-harvesting ability, charge transport capability, and photocatalytic activity. Additionally, BP–UiO demonstrates the promoted redox/acidity properties, significantly improving catalytic activity for the degradation of toluene and o-dichlorobenzene even in the presence of water. The degradation pathways of contaminants are investigated via the study of transient variations by in situ infrared (IR) methods, refined by the static analysis of intermates accumulated on the BP–UiO surface by gas chromatography–mass spectrometry (GC–MS). The electron transfer via bond construction and the combination of in situ IR and GC–MS are expected to provide a more complete theoretical basis for environmental catalysis.