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.