Quantum Chemical Approach to Redox Reactions Including Potential Dependence: Application to a Model for Hydrogen Evolution from Diamond

摘要: The evolution of H2 from diamond cathodes according to the proposed mechanism H + (aq) mC-H e f mC ¥ is treated with ab initio quantum mechanics. solvated proton and surface C-H bond are modeled molecular clusters, electron introduced at selected potentials by using a remote donor molecule. reduction occurs when affinity, EA, complex increases ionization potential, IP, as traverses its reaction coordinate. When they equal, equilibrium assumed transfer occurs. electrochemical U, given U ) (IP/eV - 4.6) V. For generation studied, coincides transitionstate structure, activation energy found decrease potential becomes more negative. It shown that bonds will re-form discharge on carbon radicals. potentialdependent examined, too. Comparison made gas-phase hydrogen present model employs hydronium ion for (aq), methane isobutane C-H, self-consistent HF/STO-3G method. In general, use an not required. This approach should find application many other reactions.