Carbon Nitride-Based Ruthenium Single Atom Photocatalyst for CO2 Reduction to Methanol

Abstract

With increasing concerns for global warming, the solar-driven photocatalytic reduction of CO₂ into chemical fuels like methanol is a propitious route to enrich energy supplies, with concomitant reduction of the abundant CO₂ stockpiles. Herein, a novel single atom-confinement and a strategy are reported toward single ruthenium atoms dispersion over porous carbon nitride surface. Ruthenium single atom character is well confirmed by EXAFS absorption spectrometric analysis unveiling the cationic coordination environment for the single-atomic-site ruthenium center, that is formed by Ru-N/C intercalation in the first coordination shell, attaining synergism in N-Ru-N connection and interfacial carrier transfer. From time resolved fluorescence decay spectra, the average carrier lifetime of the RuSA-mC₃ N₄ system is found to be higher compared to m-C₃ N₄ ; the fact uncovering the crucial role of single Ru atoms in promoting photocatalytic reaction system. A high yield of methanol (1500 µmol g^-1 cat. after 6 h of the reaction) using water as an electron donor and the reusability of the developed catalyst without any significant change in the efficiency represent the superior aspects for its potential application in real industrial technologies.

Keywords: carbon nitride; photocatalysts; photocatalytic reduction of carbon dioxide; single atom.