ABSTRACT
We present a microkinetic model for CO(2) reduction (CO(2)R) on Cu(211) towards C2 products, based on energetics estimated from an explicit solvent model. We show that the differences in both Tafel slopes and pH dependence for C1 vs C2 activity arise from differences in their multi-step mechanisms. We find the depletion in C2 products observed at high overpotential and high pH to arise from the 2nd order dependence of C-C coupling on CO coverage, which decreases due to competition from the C1 pathway. We further demonstrate that CO(2) reduction at a fixed pH yield similar activities, due to the facile kinetics for CO2 reduction to CO on Cu, which suggests C2 products to be favored for CO2R under alkaline conditions. The mechanistic insights of this work elucidate how reaction conditions can lead to significant enhancements in selectivity and activity towards higher value C2 products.
ABSTRACT
We introduce an effective technique for the calculation of the binding free energy in drug-receptor systems using nonequilibrium molecular dynamics and application of the Jarzynski theorem. In essence, this novel methodology constitutes the nonequilibrium adaptation of an ancient free energy perturbation technique called Double Annihilation Method, invented more than 25 years ago [J. Chem. Phys. 1988, 89, 3742-3746] and upon which modern approaches of binding free energy computation in drug-receptor systems are heavily based. The proposed computational approach, termed Fast Switching Double Annihilation Methods (FS-DAM) in honor of its ancient ancestor, is applied to a prototypical example system with multiple binding sites, proving its computational potential and versatility in unraveling multiple site or allosteric binding processes.