7. Nanoporous metal-based composite materials
The integration of nanoporous metals with other functional
materials would create nanoporous metal-based composites. Relatively
active nanoporous metals such as np-Cu and np-Ni can be
easily oxidized into np-metal/metal oxides composite by annealing
in air or electrochemically applied potentials [92,128]. It can be
observed from the element mapping and HRTEM that a thin oxide
film formed uniformly on the Ni ligament surface, resulting a
nanoporous composite, which can be used as a free-standing