3D-printed monolith metallic Ni-Mo Electrodes for Ultrahigh Current
Hydrogen Evolution
Abstract
In this work, we reported a series of monolithic 3D-printed Ni-Mo alloy
electrodes for highly efficient water splitting at high current density
(1500 mA cm-2) with excellent stability, which provides a solution to
scale up Ni-Mo catalysts for HER to industry use. All possible Ni-Mo
metal/alloy phases were achieved by tuning the atomic composition and
heat treatment procedure, and they were investigated through both
experiment and simulation, and the optimal NiMo phase shows the best
performance. Density functional theory (DFT) calculations elucidate that
the NiMo phase has the lowest H2O dissociation energy, which further
explains the exceptional performance of NiMo. In addition, the
microporosity was modulated via controlled thermal treatment, indicating
that the 1100 C sintered sample has the best catalytic
performance,which is attributed to the high electrochemical surface
area (ECSA). Finally, the 4 different macrostructures were achieved by
3D printing, and they further improved the catalytic performance. The
gyroid structure exhibits the best catalytic performance of driving 500
mA cm-2 at a low overpotential of 228 mV and 1500 mA cm-2 at 325 mV as
it maximizes the efficient bubble removal from the electrode surface,
which offers the great potential for high current density water
splitting.