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 - Funding Information:
The authors are indebted to thank Drs. Jeams Tomas and Ihab Obaidat for the critical readings of the manuscript and Prof. Ioannis Zuburtikudis for many fruitful discussions. We would further acknowledge the partial financial supports of the Emirates Foundation (EF-70-2010/115, grant number: 21S024 ), the UAEU program for advanced research (UPAR, grant number: 31S169 and Research-Center-based grant number: 31R068 ), and the KFUPM (research group projects: RG1502-1 and RG1502-2 ) in KSA. Last but not the least, we would like to thank Prof. Umesh V. Waghmare for providing us the access to the computational facilities at JNCASR. Appendix
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
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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 -