Sustainable one-pot construction of oxygen-rich nitrogen-doped carbon nanosheets stabilized ultrafine Rh nanoparticles for efficient ammonia borane hydrolysis

Heteroatom-doped porous carbons that possess large surface areas and well-defined porosity show great promise in heterogeneous catalysis, whereas their syntheses inevitably require complicated steps, hazardous activation and functional reagents, and an inert gas atmosphere. Herein, a one-pot synthetic strategy to oxygen-rich porous nitrogen-doped carbon (OPNC) is developed through pyrolysis of ethylenediamine tetra-acetic acid tetra-sodium in air without any activation and functionalization agents. The as-prepared OPNC with more surface oxygenated groups and mesopores not only benefits synthesis of well-dispersed ultrafine Rh nanoparticles (NPs) with abundant accessible active sites, but also facilitates the diffusion of reactants and avoids mass transfer limitations, thereby considerably contributes to a high performance toward AB hydrolysis. Specifically, the optimal Rh/OPNC exhibits a high activity toward AB hydrolysis with a turnover frequency (TOF) of 433 min(-1). The kinetic isotope studies indicate that the cleavage of O-H bond in H2O molecules is the rate-determining step (RDS). The Rh/ OPNC can be reused for five repetitive cycles with approximately 62% remained activity of the first cycle. The catalytic activity of Rh/OPNC can be further improved with a very high TOF of 1201 min(-1) in alkaline solution. This study proposes a simple and sustainable pathway to synthesize efficient catalyst support for depositing metal NPs toward AB hydrolysis. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

A simple method to prepare oxygen-rich porous nitrogen-doped carbon materials has been developed, which can be used as efficient catalyst support materials for depositing metal nanoparticles. The porous carbon material not only facilitates the synthesis of nanoparticle catalysts and enhances reaction activity, but also improves the diffusion rate of reactants and avoids mass transfer limitations.