Hydrogen
production from renewable resources, such as lignocellulosic
biomass, is highly desired, under the most sustainable and mildest
reaction conditions. In this study, a new sustainable three-step process
for the production of hydrogen has been proposed. In the first step,
a crude formic acid (CF) solution, which included typical reaction
byproducts, in particular, acetic acid, levulinic acid, saccharides,
5-hydroxymethylfurfural, furfural, and lignin, was obtained through
the combined hydrolysis/oxidation of the biomass, in the presence
of diluted sulfuric acid/hydrogen peroxide, as homogeneous catalysts.
In the second one, the distilled formic acid (DF) solution was obtained
by distillation of the CF solution, for example, by isolating liquid
byproducts, or the lignin-free CF (LCF) solution was recovered by
CF filtration for the elimination of only solid lignin particles.
In the final step, hydrogen was produced from the DF or LCF solutions
through formic acid dehydrogenation over Pd supported on amine-functionalized
mesoporous silica catalysts, in the presence of sodium formate, as
an additive. The clean hydrogen, which is produced from biomass passing
through formic acid, could be applied as an energy source of fuel
cells. This new hydrogen production process is smart, allowing the
hydrogen production with mild reaction conditions, eventually starting
from different lignocellulosic feedstocks, and it could be integrated
within the existing hydrothermal technology for levulinic acid production,
which has been already recognized as efficient and sustainable. In
addition to the production of hydrogen as an energy source of fuel
cells, formic acid derived from biomass could be utilized as a platform
chemical for chemical, agricultural, textile, leather, pharmaceutical,
and rubber industries.