Preparation and characteristic of three-dimensional NiCo alloy/carbon composite monoliths with well-defined macropores and mesostructured skeletons

Abstract

Binary NiCo alloy/carbon composite monoliths with well-defined macropores and mesostructured skeletons have been facilely fabricated by a solgel process followed by heat treatment at Ar atmosphere, and the morphology control, heat treatment and pore structures of the composite monoliths were investigated in detail. Synergic control of phase separation and solgel transition allows the formation of three-dimensional nickel–cobalt hydroxide-based xerogel monoliths with interconnected macropores and co-continuous solid skeletons. Heat treatment at 270–340 °C promotes the precipitation of nickel–cobalt oxides and the pyrolysis of PAA into carbon, and at and above 400 °C, some in situ formed carbon can carbothermally reduce nickel–cobalt oxides to generate the NiCo alloy and form NiCo alloy/carbon composites, without any deterioration of the macrostructure of monoliths. The as-prepared NiCo alloy/carbon composite monolith possesses hierarchical pore structure with a macropore size of 0.5 μm, a mesopore size of 2 nm, a specific surface area up to 167 m2 g−1 and a porosity as high as 80%. This three-dimensional hierarchically porous binary NiCo alloy/carbon monoliths are promisingly used in wide applications such as catalysis, filtration, separation, sensor.