Solvent-free synthesis of N-doped carbon-based catalyst for high-efficient reduction of 4-nitrophenol

Abstract

In this work, we report a facile, solvent-free, and one-step route for the fabrication of N-doped carbon by employing low-cost raw materials (i.e., alginic acid and ammonium chloride), which can serve as a high-efficiency metal-free catalyst for the reduction of 4-nitrophenol (4-NP). The as-prepared catalyst possesses high nitrogen content (up to 5.49 at%), high specific surface area (up to 630 m2g−1), and abundant defects, making it possible to provide sufficient active sites for the reduction of 4-NP. The excellent catalytic performance with high apparent rate constant (0.2141 min−1) and TOF value (1.33 ×10−4 mmolmg−1min−1), matches or even exceeds that of most reported metal-based catalysts. Density functional theory (DFT) calculations reveal that this excellent catalytic activity can be achieved via tuning the electron transfer and promoting the adsorption of 4-NP ions by introducing N atoms. The kinetic and thermodynamic parameters of the reaction were explored in detail, fitting well to the Langmuir-Hinshelwood model. This work not only proposes a versatile strategy to prepare advanced N-doped carbon materials but also provides useful guidance for designing and developing biomass-derived metal-free catalysts for various catalytic reactions.