Synthesis of photoluminescent m-phenylenediamine-Rhodamine B copolymer dots: selective ultrahigh photocatalytic performance for catalytic reduction of nitro-compound

The design and fabricate new metal-free photocatalysts is one of the topics in current chemistry. In this paper, we demonstrate the ultrahigh photocatalytic performance of visible light-driven metal-free photocatalyst for selective catalytic reduction of nitro-compounds. The synthesis of 1.5–4.5-nm m-phenylenediamine-Rhodamine B copolymer dots (PmRDs) via simple hydrothermal reaction of Rhodamine B and m-phenylenediamine mixed solution. The obtained PmRDs can be used as visible light-driven metal-free photocatalyst with ultrahigh photocatalytic performance for elective catalytic reduction of nitro-compounds. Due to the hydrogen-bond and specific C–N–N bonding model between the m-phenylenediamine-Rhodamine B copolymer dots (PmRDs) and nitro-compounds, the PmRDs show high photocatalytic activity and selectivity for catalytic reduction of nitro-compounds. Under the irradiation of xenon lamp, 40 ml of 1 mM 4-nitrophenol (4-PN) could be catalyzed by 12 mg catalyst within 5 min, by calculating the rate constants up to 0.766 min  −1 (25 °C). In the same way, the PmRDs are also excellent photocatalytic activity and selectivity for different nitro-compounds. Meanwhile, the efficient fast photoinduced electron transfer between the m-phenylenediamine and the Rhodamine B progress significantly improved the photocatalytic performance of PmRDs which is much higher than metal-based (such as: Ag, Ni and Cu) or metallic composite photocatalysts.