Highly efficient photocatalytic degradation over rose-like 1D/2D La(OH)3/(BiO)2OHCl heterostructures boosted by rich oxygen vacancies and enhanced interfacial charge transfer

Abstract

In this work, novel rose-like photocatalysts were successfully fabricated by constructing 1D/2D La(OH)₃ nanorod/(BiO)₂OHCl nanosheet heterojunctions. The optimal sample, BOL-2, synthesized with a Bi/La molar ratio of 4 : 1 showed significantly boosted visible-light-induced photocatalytic activity. Its kinetic rate constant (k) in the photocatalytic degradation of tetracycline (TC) and o-nitrophenol was 3.5 and 6.4 times that of (BiO)₂OHCl. The existence of rich surface oxygen vacancies (OVs) and 1D/2D heterojunctions together contributes to enhanced photocatalytic performance. The OVs broadened the light absorption range and enhanced visible light absorbance, while the formation of the La(OH)₃/(BiO)₂OHCl heterojunction by close 1D/2D interface contact improved the charge separation and transfer efficiency of BOL-2. The free radical scavenging tests and DMPO spin-trapping technology further affirmed that more ˙O₂⁻ and ˙OH as active species were generated in the presence of BOL-2 than in the presence of (BiO)₂OHCl, thereby leading to remarkably improved photocatalytic performance. BOL-2 also exhibited excellent stability in photocatalytic degradation, and the degradation efficiency only declined by 2.5% in the fourth cycle. Possible photocatalytic mechanisms as well as degradation pathways of TC over BOL-2 were explored. This work will provide new insights into the rational design of efficient photocatalysts by 1D/2D heterojunction construction and OV engineering for wastewater remediation.