Incorporating nitrogen vacancies in exfoliated B-doped g-C₃N₄ towards improved photocatalytic ciprofloxacin degradation and hydrogen evolution

Herein we have demonstrated the synthesis of nitrogen vacancy enriched exfoliated B-doped g-C₃N₄ (e-BCN) through a facile thermal exfoliation method, characterized it using different analytical techniques and compared its photocatalytic activity with that of bulk B-doped g-C₃N₄ (BCN). The decrease in peak intensity and slight shift of the 2 theta value in the PXRD patterns confirmed the successful exfoliation of bulk BCN to an e-BCN nanosheet. FESEM and HRTEM images also indicated the formation of a thin layered nanosheet of e-BCN as compared to bulk BCN. The PL and EIS data suggested the reduced recombination rate and superior separation capability of the photo-generated charge carriers of e-BCN. The introduction of nitrogen vacancies on the surface of e-BCN is confirmed by the FTIR and XPS analyses. The increased photocurrent density of 524 mu A cm^-2 displayed by e-BCN indicated the better availability of photo-generated electrons due to the higher separation of charge carriers than in the bulk BCN. The as-prepared e-BCN nanosheet exhibited enhanced photocatalytic performance 1.2 and 3.7 fold greater than that of bulk BCN towards ciprofloxacin degradation and H₂ generation, respectively, under visible light irradiation. The excellent photocatalytic behavior of e-BCN was ascribed to the augmented active sites with reduced recombination efficiency and increased separation ability of the photo-induced e(-)/h(+) pairs of the e-BCN nanosheet. This work suggested the facile fabrication of e-BCN through the thermal exfoliation process and its photocatalytic activity towards pollutant degradation and hydrogen evolution. (authors)