Nanosized copper stabilized on ternary P, N, S-doped graphene from chitosan shellfish waste: preparation and catalysis of single and double A3-type amine coupling

Abstract

Heteroatom-doping carbons are conventionally accessed through multistep procedures, often necessitating tedious postgrafting and the use of harsh conditions, while providing less-defined heterogeneous catalysts. We herein disclose a time-saving approach based on straightforward modification of chitosan, an abundant marine waste, followed by its graphitization to access texturally tunable, ternary-doped nitrogen, phosphorus, and sulfur-containing porous carbon material. The presence of functional groups in the edges ensures total exfoliation and dispersion of the sheets, whereas the presence of different coordinating sites inside accounts for efficient stabilization of the embedded metal nanoclusters. Preliminarily, good catalytic activity was noticed for the synthesis of propargylamines and dipropargylamines. The following approach combining active metals and discarded biowaste constitutes a highly versatile entry to heterogeneous carbon-based catalysts.