Multi-Scale Modeling of Copper Electrochemical Catalyst
Engineering a cost effective catalyst for electrochemical reduction of CO2 has gain interests due to its ability in sustainable energy economy and chemical industry.1 The carbon dioxide can be reduced to hydrocarbon fuel under ambient environment which would both provides an ideal storage medium for intermittent renewable energy sources and results in carbon-neutral fuel. 2
Copper is unique in reducing CO2 to a wide range of hydrocarbon compound including Carbon Monoxide, Methane, Methanol, ethylene, propane, etc.1 The main drawbacks of using copper as the catalysts are the high overpotential and low selectivity toward desired products. However, nature has the ability to use nanocluster to pin point the reduction of CO2 to desired product. Multi-scaled modeling of the catalyst will help us in better understanding the selective reduction mechanism and engineering the desired catalyst.
ICME Multiscale Approach
At the smallest length scale (~Å), electronic structure methods such as DFT will be used to determine the energetics of reduction process at metal atom surface. The potential dependence of the thermodynamic parameters for the reaction from this scale can be passed to the macroscale ISV continuum. The link to the next scale modeling will be the potential dependence of free energy. At the next length scale (>2nm), electronic structure methods such as computational hydrogen electrode model will be used to study the kinetic mechanism of the reduction process on the stabilized copper nanocluster. The potential dependent kinetic parameter can be passed up to the macroscale and describe the selectivity. The link to the next scale will be the kinetic rate determining energy.3 At the third length scale (<100nm), molecular dynamics will be used to study the thermodynamics and kinetics of CO2 binding to big molecule metal catalytic sites. The link to the macroscale ISV continuum is the selective potential. The binding energy of gas molecule on the metal atom in the electrolyte can be pass up to the next scale simulation. To the forth length scale (~ μm), molecular dynamics will be used to study the thermodynamic and kinetic behavior of CO2 reduction on big molecules. The link to the macroscale FEA continuum is the size effect on reduction reaction. The computed product yield can be passed on to next scale. At the fifth length scale (10mm), the grain morphology and crystal properties will be studied with Micro-3D. The gas dislocation motion will be linked to the macroscale ISV continuum. The properties will be passed upscale is the surface molecular interaction. At the end, with the computed result from previous scale, bulk engineered metal surface should be built with targeted selective CO2 reduction ability. The optimal result should be test with experimental method such as Gas chromatogram for gas product analysis; NMR for liquid product analysis. Justification for ICME In designing this cost effective catalyst for CO2 reduction, ICME method will save large amount of trial- and Error lab work. Instead of try thousands of size scale and surface condition, ICME determine the key effect for selective reduction. If we are able to make this engineered metal catalyst, the entire energy and chemical industry will be shifted to a sustainable and environmental friendly direction.