Preparation and characterization of activated CMK-1 with Zn and Ni species applied in hydrogen storage

JULIANA M. JUÁREZ; MARCOS B. GÓMEZ COSTA; JULIETA MUGAS ; OSCAR A. ANUNZIATA

Cancún

Congreso; XXIII International Materials Research Congress; 2014

MRS

In this work, ordered porous carbon designated as CMK-1 was synthesized by replication from MCM-48 silica, and then was modified with metals and thermal treatments under different conditions in order to gain a higher hydrogen storage capacity. Our goal was to evaluate the hydrogen storage capacities of CMK-1 replica modified with Zn and Ni nano species. The approach includes synthesis and characterization of carbon modified nanostructures along with experimental study of their adsorption capacity and storage properties. The samples were characterized by XRD, FTIR, SEM, TEM, XPS and BET methods. The nanoparticles of Zn in Zn-CMK-1 have a smaller size than nanoparticles of Ni, consequently the metal dispersion is higher and the occlusion of nanopores of the carbon framework is lower than in the case of the Ni-CMK-1. Zn nanoparticles with average diameter of ~2.5-3 nm located into the host pores, whereas NiO nanoparticles agglomerates was located on the external surface with average diameter of ∼11?14 nm We have shown that a promising hydrogen storage material can be obtained by of ordered porous carbon CMK-1 modified with Ni and Zn, which was synthesized by replication using MCM-48 as template and incorporation of metals was carried out by wetness impregnation considering both the effects of thermal treatments employing H2. The CMK-1 modified with Zn and treated with H2 at 1173 K present a better capacity for hydrogen uptake than the nanometric carbon and Ni-CMK-1 [1-4] .  This indicates the better hydrogen adsorption of the Zn-CMK-1 sample. However the Ni-CMK-1 adsorbs more amount of hydrogen than carbon at high pressures due to the interactions H2/metal or H2/metal-oxide become more evident. A hydrogen storage mechanism on metal/carbon surfaces was proposed. We can conclude this work indicating that CMK-1 hydrogen storage capacity was increase by addition of metal clusters. Also hydrogen storage behaviors onto Zn-CMK-1 and Ni-CMK-1 can be optimized by controlling the metal cluster size and dispersion and also increasing the carbon specific surface area