CO-Tolerant Heterogeneous Ruthenium Catalysts for Efficient Formic Acid Dehydrogenation

The development of improved and less costly catalysts for dehydrogenation of formic acid (HCOOH) is of general interest for renewable energy technologies involving hydrogen storage and release. Theoretical calculations reveal that ruthenium (Ru) nanoparticles supported on nitrogen-doped carbon should be appropriate catalysts for such transformations. It is predicted that nitrogen doping significantly decreases the formation of CO, but at the same time increases CO tolerance of the catalysts. To prove these hypotheses heterogeneous ruthenium catalysts supported on porous nitrogen-doped carbon (Rux/CN) with hierarchical structure were synthesized using carbon nitride (C₃N₄) as template and phenanthroline (Phen) as ligand. Experimental tests in HCOOH dehydrogenation revealed that the optimal catalyst Ru7/CN exhibited good thermal stability at 140 °C and a high turnover frequency (TOF >1300 h⁻¹), which is more than one order of magnitude higher than that of the commercial Ru5/C catalyst.