TY - JOUR
T1 - Detection of CO2 using CNT-based sensors
T2 - Role of Fe catalyst on sensitivity and selectivity
AU - Tit, Nacir
AU - Ezzi, Mohammed M.Al
AU - Abdullah, Hasan M.
AU - Yusupov, Maksudbek
AU - Kouser, Summayya
AU - Bahlouli, Hocine
AU - Yamani, Zain H.
N1 - Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2017/1/15
Y1 - 2017/1/15
N2 - The adsorption of CO2 on surfaces of graphene and carbon nanotubes (CNTs), decorated with Fe atoms, are investigated using the self-consistent-charge density-functional tight-binding (SCC-DFTB) method, neglecting the heat effects. Fe ad-atoms are more stable when they are dispersed on hollow sites. They introduce a large density of states at the Fermi level (NF); where keeping such density low would help in gas sensing. Furthermore, the Fe ad-atom can weaken the C[dbnd]O double bonds of the chemisorbed CO2 molecule, paving the way for oxygen atoms to drain more charges from Fe. Consequently, chemisorption of CO2 molecules reduces both NF and the conductance while it enhances the sensitivity with the increasing gas dose. Conducting armchair CNTs (ac-CNTs) have higher sensitivity than graphene and semiconducting zigzag CNTs (zz-CNTs). Comparative study of sensitivity of ac-CNT-Fe composite towards various gases (e.g., O2, N2, H2, H2O, CO and CO2) has shown high sensitivity and selectivity towards CO, CO2 and H2O gases.
AB - The adsorption of CO2 on surfaces of graphene and carbon nanotubes (CNTs), decorated with Fe atoms, are investigated using the self-consistent-charge density-functional tight-binding (SCC-DFTB) method, neglecting the heat effects. Fe ad-atoms are more stable when they are dispersed on hollow sites. They introduce a large density of states at the Fermi level (NF); where keeping such density low would help in gas sensing. Furthermore, the Fe ad-atom can weaken the C[dbnd]O double bonds of the chemisorbed CO2 molecule, paving the way for oxygen atoms to drain more charges from Fe. Consequently, chemisorption of CO2 molecules reduces both NF and the conductance while it enhances the sensitivity with the increasing gas dose. Conducting armchair CNTs (ac-CNTs) have higher sensitivity than graphene and semiconducting zigzag CNTs (zz-CNTs). Comparative study of sensitivity of ac-CNT-Fe composite towards various gases (e.g., O2, N2, H2, H2O, CO and CO2) has shown high sensitivity and selectivity towards CO, CO2 and H2O gases.
KW - Adsorption kinetics
KW - Carbon nanotubes
KW - Carbon-based materials
KW - Chemisorption
KW - Total-energy calculation
UR - http://www.scopus.com/inward/record.url?scp=85002694157&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85002694157&partnerID=8YFLogxK
U2 - 10.1016/j.matchemphys.2016.11.006
DO - 10.1016/j.matchemphys.2016.11.006
M3 - Article
AN - SCOPUS:85002694157
SN - 0254-0584
VL - 186
SP - 353
EP - 364
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
ER -