Graphene-protected nickel hollow fibre membrane and its application in the production of high-performance catalysts

Graphene as a protective coating has raised many interests. This ultra-thin material is chemically inert, and it is impermeable to gases and liquids, therefore it can act as a protective coating to enhance the lifespan and chemical resistance of metallic membranes. In this study, graphene protected nickel hollow fibre (G-Ni-HF) membrane was fabricated using the phase-inversion and facile single-stage sintering-chemical vapour deposition (CVD) process. The non-protected nickel hollow fibre membrane dissolved in nitric acid within a few hours, whereas the G-Ni-HF membrane remained intact. The as-prepared G-Ni-HF membrane featuring well-controlled pore structure, good chemical stability and mechanical robustness can be used in a variety of applications that involve harsh conditions. Here, we demonstrated its use in membrane emulsification to prepare TiO2 microspheres, where a highly acidic condition is essential. The microspheres prepared using G-Ni-HF membrane possess a hierarchical asymmetric egg-white structure that is distinct from the symmetric microspheres obtained by normal emulsification method. The asymmetric TiO2 microspheres also exhibit substantially improved catalytic activity to CO oxidation after impregnating with a palladium catalyst.