Chemical reduction of graphene oxide (GO) is the main route to produce the mass graphene-based materials with tailored surface chemistry and functions. However, the toxic reducing circumstances, multiple steps, and even incomplete removal of the oxygen-containing groups were involved, and the produced graphenes existed usually as the assembly-absent precipitates. Herein, a substrate-assisted reduction and assembly of GO (SARA-GO) method was developed for spontaneous formation of 3D graphene network on arbitrary conductive substrates including active and inert metals, semiconducting Si, nonmetallic carbon, and even indium-tin oxide glass without any additional reducing agents. The SARA-GO process offers a facile, efficient approach for constructing unique graphene assemblies such as microtubes, multi-channel networks, micropatterns, and allows the fabrication of high-performance binder-free rechargeable lithium-ion batteries. The versatile SARD-GO method significantly improves the processablity of graphenes, which could thus benefit many important applications in sensors and energy-related devices.

Manipulating graphene through engineering for macroscopic assemblies of practical importance is a big challenge. We develop a dually geometric confinement approach for the scalable preparation of meter-long graphene microtubings (μGTs) with a tunable diameter. They have strength comparable to graphene fiber and can be shaped to hierarchical multichannel μGT systems in a straightforward way. Of particular importance, μGTs can be selectively functionalized in a site-specific outer-wall, inner-wall, outer/inner-wall, and within-wall fashion, which endows the μGTs with unique properties for desirable applications. Apart from the magnetically and photoelectronically responsive μGTs developed here, a self-powered micromotor made of Pt inner-wall modified μGT showing agile motion in aqueous medium has been also achieved. Beyond the applications demonstrated in this study, the well-defined μGT systems can also play essential role in other important fields such as fluidics, catalysis, purification, separation, and sensing.

A one-pot solvothermal process has been developed for direct preparation of PdCu nanocapsules (with a size of ca. 10 nm) on three-dimensional (3D) graphene. Due to the 3D pore-rich network of graphene and the unique hollow structure of PdCu nanocapsules with a wall thickness of ca. 3 nm, the newly-prepared PdCu/3D graphene hybrids activated electrochemically have great electrocatalytic activity towards ethanol oxidation in alkaline media, much better than single-phase Pd and commercial E-TEK 20% Pt/C catalysts promising for application in direct ethanol fuel cells.