In situ construction of Z-scheme FeS2/Fe2O3 photocatalyst via structural transformation of pyrite for photocatalytic degradation of carbamazepine and the synergistic reduction of Cr(VI)

Pyrite is the most abundant sulfide semiconductor mineral with excellent optical properties . However, few reports have investigated its photocatalytic activity because of the low photogenerated carrier separation efficiency. In this work, a Z-scheme FeS 2 /Fe 2 O 3 composite photocatalyst was fabricated in situ via structural transformation of pyrite through heat treatment. A remarkably enhanced photocatalytic performance was observed over the FeS 2 /Fe 2 O 3 composite photocatalyst. Compared with the pristine pyrite, the degradation efficiency of carbamazepine (CBZ) reached 65% at the added hexavalent chromium (Cr(Ⅵ)) concentration of 20 mg/L and the Cr(Ⅵ) was nearly completely reduced in the mixed system using FeS 2 /Fe 2 O 3 within 30 min under simulated solar light irradiation. The enhanced photocatalytic activity can be attributed to the efficient separation and transfer of photogenerated carriers in the FeS 2 /Fe 2 O 3 composite photocatalyst. This facilitated the generation of •OH, hole (h + ) and •O 2 − species, which participated in the photocatalytic reaction with CBZ. Based on the measurement of the active species and electric properties, a Z-scheme electron transfer pathway was proposed for the FeS 2 /Fe 2 O 3 composite photocatalyst. This work broadens the application potential of pyrite in environmental remediation.