3D porous alumina/graphene hybrids prepared by atomic layer deposition and their performance for water treatment

Metal / carbon hybrids have impressive potential of applications in many fields: catalysis, energy conversion and storage, environmental. However, further efforts are needed to achieve a better control of homogeneity of the metal oxide deposit on the carbon surface to provide reliable synthesis approaches of metal / carbon hybrids. In this work, atomic layer deposition is used to prepare 3D porous alumina / reduced graphene oxide hybrid monoliths. We show that atomic layer deposition, even though rarely reported to prepare metal oxide / carbon hybrids, allows a conformal coating onto the graphene nanosheet surface. In-depth advanced characterization have been performed thanks to a coupled approach consisting of the preparation of lamellas of the porous hybrid by means of focused ion beam and their analysis by transmission electron microscopy. A good accessibility of the alumina precursors to the internal surface of the prepared 3D porous carbon monoliths was evidenced. The alumina / graphene hybrid prepared with 50 cycles of ALD deposit has a surface as high as 284 m2/g. As a proofof-concept for the interest of the designed hybrids, they are tested for the removal of Congo red, a standard organic dye pollutant. 87 and 98 % of Congo red removal were reached at the first and the second step of adsorption proving the good adsorption performance and reusability ability of the de designed hybrid adsorbents. We believe that such multi-porous 3D alumina / graphene macrostructures that offers a favorable accessibility to the adsorption sites open interesting potentialities for pollution remediation applications.