One-pot synthesis of carbon dots/hydrochar and visible-light-driven photocatalysts for aerobic oxidative coupling of benzylic amines

Abstract

Utilizing selective photocatalysis conversion of amines represents an environmentally sustainable and economically feasible approach to generating valuable chemical products in the industry. Herein, carbon dots (CDs) incorporated in hydrochar (CDs/HCPP) were synthesized by one-pot hydrothermal carbonization of pomelo peel (PP) coupled with freeze-drying and used for aerobic oxidative coupling of benzylic amines. CDs were produced using only the pomelo peel as the carbon source, without the addition of any extra carbon additives. CDs/HCPP exhibited the greatest catalytic activity, achieving a benzylamine conversion rate of 99%, which was nearly 5.5 times of carbonized PP (CPP) without CDs and 1.14 times of CDs alone. Additionally, the oxidation of other amines, such as p-substituted benzylamines with groups that donate and withdraw electrons, was also demonstrated to be highly active and reusable using CDs/HCPP. This study has the potential to pave the way for novel methodologies and insights into synthesizing biomass composites adorned with CDs, enhancing the efficacy of photocatalytic syntheses.

Keywords

Carbon dots/hydrochar / metal-free photocatalysts / photocatalytic oxidative coupling of amine / imine

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