Black Phosphorus Quantum Dots/Carbon Nitride-Reduced Graphene Oxide Ternary Heterojunction as a Multifunctional Metal-Free Photocatalyst for Photooxidation Reactions

We report herein a rationally designed metal-free ternary heterojunction, namely, black phosphorus quantum dots/carbon nitride-reduced graphene oxide (BPQDs/CN-rGO), that functions as a photocatalyst in multiple photooxidation reactions including C═C bond cleavage, glycerol oxidation, and C–CF3 bond formation along with the removal of organic pollutants from wastewater. After the characterization of the structure and photophysical properties of BPQDs/CN-rGO heterojunction, it was first tested in the photodegradation of organic pollutants and showed superior performance. The underlying mechanism of BPQDs/CN-rGO in the photodegradation of organic pollutants revealed that the created internal electric field (IEF) among the components and photogenerated species (h+ and O2•–) are attributed to superior activity. Prompted by these results, the BPQDs/CN-rGO photocatalyst was applied in other photooxidation reactions. The nonclassical-type-II heterojunction structure generates active species (O2•–, h+, 1O2) under visible light irradiation, enabling the selective oxidation of glycerol to glyceric acid and C═C bond cleavage along with highly challenging Langlois reagent to CF3-functionalized heteroarenes.