Organizing a post-fossil
fuel economy requires the development
of sustainable energy carriers. Hydrogen is expected to play a significant
role as an alternative fuel as it is among the most efficient energy
carriers. Therefore, nowadays, the demand for hydrogen production
is increasing. Green hydrogen produced by water splitting produces
zero carbon emissions but requires the use of expensive catalysts.
Therefore, the demand for efficient and economical catalysts is constantly
growing. Transition-metal carbides, and especially Mo2C,
have attracted great attention from the scientific community since
they are abundantly available and hold great promises for efficient
performance toward the hydrogen evolution reaction (HER). This study
presents a bottom-up approach for depositing Mo carbide nanostructures
on vertical graphene nanowall templates via chemical vapor deposition,
magnetron sputtering, and thermal annealing processes. Electrochemical
results highlight the importance of adequate loading of graphene templates
with the optimum amount of Mo carbides, controlled by both deposition
and annealing time, to enrich the available active sites. The resulting
compounds exhibit exceptional activities toward the HER in acidic
media, requiring overpotentials of 82 mV at −10 mA/cm2and demonstrating a Tafel slope of 56 mV/dec. The high double-layer
capacitance and low charge transfer resistance of these Mo2C on GNW hybrid compounds are the main causes of the enhanced HER
activity. This study is expected to pave the way for the design of
hybrid nanostructures based on nanocatalyst deposition on three-dimensional
graphene templates.