Carboxylated cellulose-derived carbon mediated flower-like bismuth oxyhalides for efficient Cr(VI) reduction under visible light

Abstract

Exquisitely tailoring the morphologies of photocatalysts could achieve high activities. In this study, the morphological transformation of bismuth oxyhalide (BiOX, X = Br, I and Cl) from disordered lamellae to regular flowers was facilely achieved via the use of carboxylated cellulose-derived carbon (CDC). The sphere-like structure and abundant surface functional groups of CDC induce the formation of such flower-like morphologies of BiOX/CDC, and this morphology results in a pronounced increase in surface area (e.g., the surface area of BiOBr increases from 3 to 106 m2 g−1) and porosity. Combined with the good light absorption and conductivity of CDC, the flower-like BiOX/CDC exhibited impressive photocatalytic activity under visible light. Regarding the probing Cr(VI) reduction reaction, the representative BiOBr/CDC is capable of reducing 98% of Cr(VI) within 30 min of visible-light illumination, which is markedly greater than those of pure BiOBr (6%) and CDC (16%). Likewise, BiOI/CDC and BiOCl/CDC also have decent photocatalytic Cr(VI) reduction capacities (89% for BiOI/CDC and 69% for BiOCl/CDC) under visible light in comparison with pristine BiOI (13%) and BiOCl (1.5%). This work furnishes a novel and facile approach to tune photocatalyst morphologies and sheds light on the great potential of biomass-derived carbon, which may enlighten the judicious design of photocatalysts with high efficiency.