Preparation of S- scheme heterojunction Bi28O32 (SO4)10/NiAl LDH for efficient photocatalytic degradation of tetracycline

At present, the construction of high-efficiency photocatalytic degradation system of antibiotic pollutants has become a research hotspot. In this paper, Bi₂₈O₃₂(SO₄)₁₀/NiAl LDH photocatalyst with three-dimensional spherical morphology was successfully prepared by hydrothermal method followed by calcination, thus applying to the degradation of tetracycline. The characterization and photochemical analysis of the resulted material were used to determine the type of formed heterojunction. Bi₂₈O₃₂(SO₄)₁₀ and NiAl LDH build a close contact interface. The matching band gap structure makes S-scheme heterojunction formed between the two single component. Benefited from this structure, the Bi₂₈O₃₂(SO₄)₁₀/NiAl LDH composite with the mass ratio of 1:1 exhibited 95% efficiency in degradation of tetracycline after irradiation for 120 min, and it is stable, reusable and universal. The apparent rate constant of TC degradation by heterojunction catalyst is greatly increased, which is 5.35 and 4.91 times that of Bi₂₈O₃₂(SO₄)₁₀ and NiAl LDH. Overall, this paper provides a way of thinking for the design of new bismuth based photocatalytic materials, and thus providing a reference for the rational design of S-scheme heterojunction.