A series of alumina supported Ru nanoparticles (Ru γ -Al2O3-x (x=2-10 Ru wt%) was synthesized
using the ethylene glycol reduction method. XRD, TEM, EDX, H2-chemisorption, XPS and
H2-TPD analytical techniques were used to understand the physiochemical nature of alumina supported
Ru nanoparticles. All the well-characterized Ru#Al2O3-x (x=2-10 Ru wt%) catalysts were used for
high-pressure CO2 hydrogenation to formic acid synthesis. A clear correlation was recorded between
the physiochemical properties of developed catalysts and the molar quantity of formic acid. Among all
the developed catalysts, Ru#Al2O3-2 catalyst with or without ionic liquid reaction medium gave a good
molar quantity of formic acid. Application of ionic liquid was also expanded, and ionic liquid medium
appeared as a good solvent system as compared to the amine solvent system, which not only provides
better solubility of reactants and catalysts but also found useful in the easy recovery of formic acid after
the completion of the reaction. The catalyst recycled seven times with easy product isolation stem to
make this system very useful and fulfill the requirement of sustainable chemistry.
Heterogeneous catalysts for CO2 hydrogenation to formic acid/formate: from nanoscale to single atom
