Covalent organic framework derived synthesis of Ru embedded in carbon nitride for hydrogen and oxygen evolution reactions

Abstract

The hydrogen and oxygen evolution reactions (HER and OER) are two steps in electrochemical water splitting for conversion of electric power to chemical energy. The main challenge remains the development of efficient, stable and cheap electrocatalysts able to perform both reactions under alkaline conditions. Single atom Ru stabilized by nitrogen-doped carbon and RuO₂ are currently the materials of choice for the HER and OER, respectively. Here, we propose a strategy for the preparation of Ru embedded in a carbon nitride matrix for efficient HER and OER in KOH solution. It is based on the preparation of a covalent organic framework 2D CIN-1 structure with coordinated Ru^II, producing Ru oxide nanoparticles with low valence Ru sites arranged in the form of nanowires between layers of graphitic carbon nitride after pyrolysis. The material demonstrates smaller overpotentials for the HER and OER in comparison with benchmark Pt and RuO₂ catalysts, and high catalytic stability.