(6hs) Rational Design of High-Performance Catalysts for Sustainable Energy Conversion and Storage

Authors: 
García-Melchor, M., Stanford University

It is widely known that in the not-too-distant future the world’s energy dependence on fossil fuels resources will have to be replaced by a more sustainable energy source. However, the energy supply from these sources is intermittent. Moreover, the fact that the usage of electricity fluctuates independently leads to an unavoidable continuous mismatch between supply and demand. One solution would be the use of sunlight to make solar fuels by artificial photosynthesis, such as the water splitting into gaseous hydrogen and oxygen, or the water reduction of CO2to methanol or hydrocarbons (Eqs. 1-3).

2H2O − 4e- ↔ O2 + 4H+                        (Eq. 1)

CO2 + 6 H+ + 6 e- ↔ CH3OH + H2O       (Eq. 2)

CO2 + 8 H+ + 8 e- ↔ CH4 + 2H2O          (Eq. 3)

A key half reaction in all the above processes is the oxidation of water to molecular oxygen, also known as oxygen evolution reaction (OER). This reaction is particularly difficult as it involves the removal of four electrons and protons from two water molecules and the formation of an O−O bond. Hence, there is an urgent need for finding a material that can catalyze this reaction in a very efficient way. This is precisely the main focus of my research, that is, the development of economic and highly efficient catalysts for the OER. To tackle this challenge, I use state-of-the-art theoretical calculations in order to get a fundamental understanding of the overall process, e.g. reaction mechanism, electronic structure of different catalysts, etc. This allows me to identify what are the main requirements that a potential high-performance OER catalyst needs to fulfill. The idea of this rational catalyst design is to be able to propose some candidates that can be tested by my experimental collaborators and that eventually will lead to a promising OER catalyst that can be scaled up for its industrial application.