Atomic-Scale Carbon Framework Reconstruction Enables Record Nitrogen-Doping Up to 33.8 At% in Graphene Nanoribbon

Abstract

Nitrogen-doping is well-known to be an effective and promising strategy to tune the electronic states and configuration of carbon materials for catalysis, energy conversion and storage. Since 2009, numerous investigations have demonstrated that the catalytic activity of the nitrogen-doped carbon materials can be improved with an increasing nitrogen-doping concentration, yet, how to realize a high doping level remains a great challenge, and to what level remains an open and elusive question. Herein, we report an “in situ framework reconstruction of g-C₃N₄ ” that can provide a suitable and simple approach for Nitrogen-superdoping, where nitrogen vacancies formed at C-N=C sites in the g-C₃N₄ framework help to activate adjacent C atoms that are endowed with unpaired electrons dwelling, thus, to be more active. Importantly, density functional theory analysis and certified experiments reveal that they are energetically favorable to bond with an ethene molecule, reconstructing a π-bonded dual nitrogen-doped hexagonal-C ring that further acts as building blocks of the as-formed graphene nanoribbons. Finally, the doping level of nitrogen and the configuration can be finely tuned in a wide range, and up to 33.8 at% of nitrogen is homogenously doped. With the Nitrogen-superdoped graphene nanoribbons as catalyst for triiodide reduction, a power conversion efficiency of 8.60 % is achieved. This present work represents a breakthrough in high-efficiency nitrogen-doping of carbon materials, and will full fast promote the chemistry, chemical engeering and material industry involved in carbon.

Keywords: graphitic carbon nitride, nitrogen vacancy, framework reconstruction, pyridinic nitrogen, nitrogen-superdoping.