Preparation of visible-light photocatalysts of Bi2O3/Bi embedded in porous carbon from Bi-based metal organic frameworks for highly efficient Rhodamine B removal from water

A series of ternary composite photocatalysts of Bi2O3/Bi embedded in porous carbon (Bi2O3/Bi/PC) was prepared by the high-temperature pyrolysis of a bismuth-based metal organic framework (CAU-17(Bi)). They were used as photocatalysts for the degradation of organic Rhodamine B dye (RhB) in water under visible light. Results showed that the Bi2O3/Bi/PC composites with different Bi2O3/Bi ratios could be obtained through changing the extent of the carbothermal reduction of Bi2O3 during pyrolysis. The photocatalystpyrolyzed at 800 oC showed the highest photocatalytic performance and had a wide applicable pH value range and excellent recyclability and stability.The components in the ternary composites exhibited a synergetic effect in the removal of RhB, where Bi2O3 acted as a low-band gap semiconductor, metallic Bi transferred electrons generated by visible light excitation to the graphitic structure in porous carbon to inhibit the recombination of electrons with holes. The holes and peroxide radicals were the main active species. This study provides a new way for the design and preparation of visible-light active and high-performance photocatalysts for organic contaminant degradation in aqueous media by using metal organic frameworks as a multicomponent precursor.