Synthesis of Hollow BiOCl-Decorated Bimetallic MOF(Bi/In)/Ti3C2T x MXene for the Photodegradation of Rhodamine B

Abstract Hollow microspherical bimetallic metal-organic frameworks (MOFs) were formed in situ in the presence of bismuth (Bi3+) and indium (In3+) cations, which serve as the primary components of the MOF secondary building units. In contrast, the monometallic counterparts, Bi-MOF and In-MOF, exhibited distinct morphologies: polyhedral particles and microrods, respectively. Morphological and structural analyses revealed that the hollow microspheres are composed of bismuth oxychloride (BiOCl)-like nanosheets, with the InCl3 precursor supplying chloride ions necessary for BiOCl formation. Three-dimensional Bi/In-MOF was hybridized with two-dimensional Ti3C2 MXene in various proportions via a solvothermal process to produce Bi/In-MOF/Ti3C2 composites, which demonstrated high performance in the photodegradation of rhodamine B (RhB). Incorporation of 10 wt % Ti3C2 and varying amounts of Bi/In-MOFs resulted in a narrowed band gap (∼2.6 eV) and suppressed charge-carrier recombination compared to the bimetallic MOF alone (∼3.18 eV), thereby enhancing visible-light photocatalytic efficiency. The Bi/In-MOF(20 wt % In)/Ti3C2(10 wt %) composite achieved a 95% RhB degradation efficiency under visible-light irradiation (100 W LED) within 80 min. Scavenger experiments identified superoxide radicals (O2•–) and holes (h+) as the dominant reactive species responsible for RhB degradation. The photocatalyst also demonstrated excellent structural stability, retaining 87% degradation efficiency after four reuse cycles.