Preparation of core–shell structured Cu2O@NH2-MIL-125(Ti) MOF and efficient photocatalytic degradation of methylene blue

Abstract

Cu₂O has garnered increased interest due to its ideal band gap and excellent carrier separation efficiency for photo catalysis; nonetheless, charge recombination still causes instability in practical usage. Here we design and fabricate Truncated cube Cu₂O(T C)@NH₂-MIL-125(Ti) core–shell. The main bonds formed between NH₂-MIL-125(Ti) and T C are through the NCuN, NOCu bond and the CuO surface interaction in addition formed. The Truncated cube shape of Cu₂O as a core and NH₂-MIL-125(Ti) shell with limited recombination is seldom researched. The rate constant (K) for the photocatalytic methylene blue degradation of Cu₂O(T C)@NH₂-MIL-125(Ti) was 0.0182 min⁻¹, 3.35 times higher than that of pure TC. The closely spaced band structures and close contact surfaces between T C and NH₂-MIL-125(Ti) should be the origin of the core–shell’s increased photocatalytic activity, as they facilitate the efficient transfer and separation of the photo-generated charge carriers. Cu²⁺ proportion to Cu¹⁺ after core–shell preparation is 45.66 %, which causes more oxygen vacancy and charge imbalances, increasing reactant adsorption and light absorption in the visible spectrum. The stability test towards MB employing T C@NH_2-MIL-125(Ti) core–shell and the photocatalytic scavenger test have also been studied. Moreover, a Type-II heterojunction was produced by photo-generated electron transfer from T C to NH₂-MIL-125(Ti). Such a heterostructure sheds light on Cu₂O-related core–shell materials’ exceptionally effective recombination suppression and improved photocatalytic effectiveness.