Vertical interface coupling between crystalline α-Fe2O3 and carbon nitride nanosheets for efficient degradation of organic pollutants

The interface coupling of crystalline catalytic materials exhibits unique functions in removing pollutants and purifying water resources; however, little attention has been paid to the effect of different crystal surface coupling on photogenerated charge separation. In this study, different coupling facets of α-Fe2O3 were constructed on cyclized carbon nitride (ACN) by impregnation hydrothermal method, and the coupling mechanism of α-Fe2O3 crystal facets on ACN was explained. The α-Fe2O3 nanosheets can be assembled parallelly or vertically on the surface of ACN due to the surface energy of α-Fe2O3 crystal facets and the different surface charges of ACN. The Z-scheme heterojunction formed by different interface coupling between α-Fe2O3 and ACN improved the separation efficiencies of photogenerated carriers. The photodegradation of organic pollutants and antibiotics showed that the photoactivity of Fe110/ACN+ was much higher than that of ACN, ACN+ and Fe001/ACN. The maximum removal rate of oxytetracycline by Fe110/ACN+ composites was 88.6%, and it had excellent adsorption and catalytic effect on organic dye Congo red within 120 min. Overall, the work may provide a new perspective for designing structures of unique crystal surface coupling and constructing heterojunctions with high catalytic performance.