Improved performance of visible-light photocatalytic H_(2)-production and Cr(Ⅵ) reduction by waste pigeon guano doped g-C_(3)N_(4) nanosheets

In this study,waste pigeon guano(PG)was re-utilized as an ideal biomass adulterant to improve the photocatalytic activity of the pristine graphitic carbon nitride(g-C_(3)N_(4)).Waste PG and melamine were employed as precursors to fabricate a novel porous multielement-doped g-C_(3)N_(4)(CN-PG-S)nanosheets photocatalyst via in situ thermal polycondensation coupled with thermal exfoliation strategy.The CN-PG-S owned abundant uniformly porous structures,superior conductivity,and excellent photocatalytic abilities,resulting in highly-efficient H_(2)-production(1950μmol g^(–1) h^(–1))and Cr(Ⅵ)reduction(99.1%)un-der visible light,which increased by 22.9-folds and 5.3-folds more than that of pristine g-C_(3)N_(4).The non-metallic(P,S,and O)and metallic elements in CN-PG-S played a crucial role in expanding the visible-light absorption range and promoting the separation-migration of photogenerated electron-hole pairs.And the uniformly porous nanosheet structure of CN-PG-S shortens the diffusion paths of photogenerated carri-ers and exposes more active sites for photocatalytic reactions.This study proposed an eco-friendly re-sources integration strategy of waste PG to prepare excellent CN-PG-S photocatalysts for highly-efficient H_(2)-production and Cr(VI)reduction.