Synthesis and characterization of MCM-48 carbon replica modified with Zn and Ni applied in hydrogen storage

JULIANA M. JUÁREZ; MARCOS B. GOMEZ; OSCAR A. ANUNZIATA

Madrid

Congreso; International conference on diamond and carbon materials; 2014

Elsevier

The aim of this work is to synthesize a mesoporous carbon CMK-1 modified with Zn in order to increase its capacity in hydrogen storage. The approach that we have followed includes synthesis of nanostructures with the experimental study of its adsorption capacity and storage properties. Ordered nanoporous carbon CMK-1 was synthesized via two step impregnation of the siliceous mesopores MCM-48, with a solution of sucrose using an incipient wetness method. The sucrose?silica composite was then heated at 1173 K for 4 h under nitrogen flow. The silica template was dissolved with 5 wt% hydrofluoric acid in order to remove the silica. The template-free carbon product obtained was filtered, washed with deionized water and ethanol, and dried. Zn-CMK-1 was prepared by wet impregnation using Zn (NO3)2.6H2O as source of Zn. In order to increase the amount of hydrogen adsorbed the sample of Zn-CMK-1 was treated under H2 flow Porous carbon CMK-1 and the samples modified with Zn were characterized by XRD, FTIR, XPS, BET, TEM and SEM. These studies indicate that it was possible to obtain a CMK-1 replica successfully from MCM-48, using sucrose as a carbon precursor. The nanoparticles of Zn in Zn-CMK-1 have a smal size (~2.5-3 nm), consequently it has a high metal dispersion and the occlusion of nanopores of the carbon framework is low. In summary, we have shown that CMK-1 ordered porous carbon modified with metals is a promising material for hydrogen storage. The CMK-1 modified with Zn showed the highest H2 uptake at low and high pressures (4.4 wt. % of H2 sorption at 10 bar and 77 K).