Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 84: Focus Session: Semiconductor Materials and Nanostructure for Photocatalysis

O 84.7: Hauptvortrag

Donnerstag, 23. März 2017, 12:00–12:30, POT 51

Photo-electrochemistry modelling beyond idealised surfaces and the computational hydrogen electrode — •Harald Oberhofer — Technical University Munich Garching, Germany

The role computer modelling plays today in understanding and optimising catalysts for photo-electrochemical reactions is undisputed. Yet, state of the art simulation approaches tend to rely on a number of assumptions and simplifications which---according to newest results---may not be fully justified. For example, simulation of the all-important electro-catalytic water oxidation reaction is mainly based on idealised surfaces and the computational hydrogen electrode (CHE) approach, which evaluates the thermodynamic feasibility of a catalyst looking at pathway where each hydrogen abstraction is coupled to the removal of one electron (PCET). The precise reactive site of the catalyst is thereby viewed as irrelevant, based on the premise of idealised surfaces. Yet, especially on semi-conducting catalysts both the assumption of PCET and of pristine, defect-free catalyst surfaces are not necessarily fulfilled.

The great success of the CHE approach is in part due to its low computational cost allowing a computational screening of suitable catalyst materials. Any other scheme going beyond PCET and pristine surfaces should therefore match this advantage, ideally avoiding costly numerical sampling of solvent degrees of freedom. Yet, recent developments in thermodynamic modelling as well as embedding techniques, both liquid and solid-state, especially considering the interface between catalyst and solvent, point the way towards photo-electrochemistry modelling beyond the computational hydrogen electrode.