Hydrogen production by heterogeneous catalytic dehydrogenation of formic acid. A review

The review considers recent advances in the field of heterogeneous metal-containing catalysts for the production of hydrogen as an environmentally benign energy carrier by dehydrogenation of formic acid, which is an accessible and low-toxic substance. Although the activity of homogeneous catalysts in the dehydrogenation of formic acid is higher compared to heterogeneous catalysts, the application of the latter ones makes it possible to simplify the technology and increase the environmental safety of hydrogen production from formic acid. The efficiency of heterogeneous catalysts for dehydrogenation of formic acid based on noble metals (Pd, Au, Ag) can be enhanced by the development of advanced methods for the synthesis of monometallic, bimetallic and trimetallic nanoparticles on different supports. The efficiency of different heterogeneous nanocatalysts in dehydrogenation of formic acid is compared and various factors (the nature of a metal, the size of nanoparticles, their composition, and features of the support) affecting their activity and selectivity to hydrogen are discussed. A considerable increase in the activity toward dehydrogenation of formic acid is achieved by enhancing the interaction of metal nanoparticles with the surface of chemically modified substrate, which decreases the size of nanoparticles, increases the uniformity of their distribution over the substrate and changes the electronic state of the metal. Advances in the development of industrial heterogeneous catalysts for the production of pure hydrogen from formic acid will ensure an essential contribution to the development of hydrogen energetics.