Reduced graphene oxide (rGO)-copper oxide nanocomposites were prepared by covalent grafting of CuO nanorods on the rGO skeleton. The chemical and structural features of rGO-CuO nanocomposites were studied by FTIR, XPS, XRD and HRTEM analyses. Photocatalytic potential of rGO-CuO nanocomposites was explored for reduction of CO2 into the methanol under visible light irradiation. The breadth of CuO nanorods and the oxidation state of Cu in rGO-CuO/Cu2O nanocomposites were systematically varied to investigate their porosity and photocatalytic activities. The pristine CuO nanorods exhibited very low activity because of fast recombination of charge carriers and yielded methanol only 175 µmol g-1, whereas rGO-Cu2O and rGO-CuO exhibited significantly improved photocatalytic activities and yielded five (862 µmol g-1) and seven (1228 µmol g-1) times more methanol, respectively. The superior photocatalytic activities of CuO in rGO-CuO nanocomposites were attributed to the slow recombination of charge carriers and efficient transfer of photo-generated electrons through the rGO skeleton. This study further excludes the use of scavenging donor.
Quick Coarse-grained kinetic Monte Carlo overviewStuart Collins
Overviews the motivation and underworkings of kinetic Monte Carlo, a computer simulation method used to study subjects from biological cell membranes to reactions on platinum surfaces. Then expands kMC to CGMC - a method for speeding up the simulation by averaging out details deemed unimportant to the overall outcome of the simulation.
Reduced graphene oxide (rGO)-copper oxide nanocomposites were prepared by covalent grafting of CuO nanorods on the rGO skeleton. The chemical and structural features of rGO-CuO nanocomposites were studied by FTIR, XPS, XRD and HRTEM analyses. Photocatalytic potential of rGO-CuO nanocomposites was explored for reduction of CO2 into the methanol under visible light irradiation. The breadth of CuO nanorods and the oxidation state of Cu in rGO-CuO/Cu2O nanocomposites were systematically varied to investigate their porosity and photocatalytic activities. The pristine CuO nanorods exhibited very low activity because of fast recombination of charge carriers and yielded methanol only 175 µmol g-1, whereas rGO-Cu2O and rGO-CuO exhibited significantly improved photocatalytic activities and yielded five (862 µmol g-1) and seven (1228 µmol g-1) times more methanol, respectively. The superior photocatalytic activities of CuO in rGO-CuO nanocomposites were attributed to the slow recombination of charge carriers and efficient transfer of photo-generated electrons through the rGO skeleton. This study further excludes the use of scavenging donor.
Quick Coarse-grained kinetic Monte Carlo overviewStuart Collins
Overviews the motivation and underworkings of kinetic Monte Carlo, a computer simulation method used to study subjects from biological cell membranes to reactions on platinum surfaces. Then expands kMC to CGMC - a method for speeding up the simulation by averaging out details deemed unimportant to the overall outcome of the simulation.
Nano Technology & Nano Materials
by Ray Fernando, PHD
California Polytechnic State University
Polymers and Coatings Program
Department of Chemistry and Biochemistry
San Luis Obispo, CA
www.polymerscoatings.calpoly.edu
Delivered 22 June 2009 @ SLINTEC
Nano Technology & Nano Materials
by Ray Fernando, PHD
California Polytechnic State University
Polymers and Coatings Program
Department of Chemistry and Biochemistry
San Luis Obispo, CA
www.polymerscoatings.calpoly.edu
Delivered 22 June 2009 @ SLINTEC
First Principles Thermodynamics and Kinetic Monte Carlo Simulations: A case study of LaMnO3 (001) surface
1. First Principles Kinetic Monte Carlo
Simulations of Oxygen Interaction with
LaMnO3 Perovskite Surface
Ghanshyam Pilania and R. Ramprasad
Institute of Materials Science,
University of Connecticut
MRS Fall Meeting 2011
SESSION B10/C6: Joint Session: SOFC Materials Characterization II
2. Oxygen Interactions with Perovskites:
Applications
Solid oxide fuel cells NO oxidation Photocatalytic H2O
splitting
O2 H2
Catalytic H2O H2O
Converter
O2
Sr doped Triple-phase
LaMnO3 boundary
O-2
YSZ
J. Fleig, Annu. Rev. Mater. Res. 33, 361 (2003). Chang Hwan Kim, et al. Science 327, 1624 (2010) Kudo et al. Chem. Soc. Rev., 2009, 38, 253–278
7. Limitations of the FPT approach
•Configurational entropy is not taken into
account
•Treatment of “large” systems may not
be practical
•Metastability can not be captured
•Kinetic aspects
8. Kinetic Monte Carlo Simulations
Method Highlights
•DFT fitted 2-D lattice gas Hamiltonian
•Lateral interactions between the
adsorbates
•Activation barriers within DFT nudged
elastic band Method
•Local environment dependent activation
barriers
10. Kinetic Monte Carlo Simulations
“Metastable” Phase diagrams
O+O2 partial'coverage'- partial'coverage'-
O2#Condensation## covered of'atomic'O O2#Condensation## of'atomic'O
100#%#O# 100#%#O#
100%O2
O+O2
Clean surface Clean surface
Starting from a clean surface at 100 K and
Starting from a clean surface at any given
ramping up the temperature at a given
temperature and pressure.
pressure.
R. Spinicci et al. Journal of Molecular Catalysis A: Chemical 197 (2003) 147–155