Remarkable Improvement in the Mechanical Properties and CO2 Uptake of MOFs Brought About by Covalent Linking to Graphene.
Metal-organic frameworks (MOFs) are exceptional as gas adsorbents but their mechanical properties are poor. We present a successful strategy to improve the mechanical properties along with gas adsorption characteristics, wherein graphene (Gr) is covalently bonded with M/DOBDC (M=Mg(2+) , Ni(2+) , or Co(2+) , DOBDC=2,5-dioxido-1,4-benzene dicarboxylate) MOFs. The surface area of the graphene-MOF composites increases up to 200-300 m(2)  g(-1) whereas the CO2 uptake increases by ca. 3-5 wt % at 0.15 atm and by 6-10 wt % at 1 atm. What is significant is that the composites exhibit improved mechanical properties. In the case of Mg/DOBDC, a three-fold increase in both the elastic modulus and hardness with 5 wt % graphene reinforcement is observed. Improvement in both the mechanical properties and gas adsorption characteristics of porous MOFs on linking them to graphene is a novel observation and suggests a new avenue for the design and synthesis of porous materials.
Chemistry and Physics of Materials Unit, New Chemistry Unit, Sheikh Saqr Laboratory, International Centre for Materials Science (ICMS), CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore-, 560064, India.
Ram
R
Kumar
Department of Materials Engineering, Indian Institute of Science, Bangalore-, 560012, India.
Devaraj
D
Raut
Department of Materials Engineering, Indian Institute of Science, Bangalore-, 560012, India.
Upadrasta
U
Ramamurty
Chemistry and Physics of Materials Unit, New Chemistry Unit, Sheikh Saqr Laboratory, International Centre for Materials Science (ICMS), CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore-, 560064, India. cnrrao@jncasr.ac.in.
C N R
CN
Rao
CO2 uptake; composite material; graphene; mechanical properties; metal-organic frameworks