Photo-derived fixation of dinitrogen into ammonia at ambient condition with water on ruthenium/coal-based carbon nanosheets.

Photocatalytic synthesis of ammonia is a kind of compelling and challenging nitrogen fixation method. In this paper, we extract the small-sized graphite-like carbon layer in the coal by organic solvent extraction method using HNO3 pretreated coal as a precursor. Then the coal-based carbon nanosheets (CNs) containing with Ca2+, Ti4+, Fe2+, Al3+, Si4+, C, N, O and other metal/non-metal ions was obtained under the assistance of the ultrasonication. The composite catalyst Ru/CNs was prepared by in situ loading the ruthenium (Ru) nanoparticles reduced from RuCl3·3H2O onto the as prepared CNs. The structure was characterized and the photocatalytic nitrogen fixation into ammonia performance under ambient temperature and atmospheric pressure was studied. The results show that the composite catalyst Ru/CNs with uniform dispersion of Ru nanoparticles on CNs has excellent photocatalytic nitrogen fixation activity, and the NH3 yield reaches 221.3 μmol/L after the reaction for 4 h. At the same time, the as prepared catalyst had quite good stability, and the NH3 yield remained substantially unchanged in 5 cycle experiments.