Facile synthesis of NiFe-CO32--LDH/Sn4+--Bi2O3 microsphere S-Scheme heterojunction for efficient tetracycline photodegradation and hydrogen production

In this work, the micro spherical NiFe-CO32--LDH/Sn4+-beta-Bi2O3 heterojunction composites are prepared through an in situ intercalation process. The photocatalytic degradation of tetracycline and hydrogen evolution of the composites are evaluated under visible light. The results show that the composites present a degradation efficiency up to 98.28% for tetracycline within 1 h with the kinetic rate constant k at 0.06198 min-1, which is 4.94 and 6.96 times that of beta-Bi2O3 and NiFe-CO32--LDH. Then, the different reaction conditions, such as the catalyst amount, antibiotics concentration, pH in solution, and different inorganic anions addition are systematic investigated. Base on the physical and chemical characterization and electrochemical testing, the heavily improved photocatalytic performance of the NiFe-CO32--LDH/Sn4+-beta-Bi2O3 composites can be attributed to the increased specific surface area, excellent separation efficiency of photoelectron-hole pairs, as well as the establishment of the S-scheme heterojunction.