Paulino Monroy Castillero

Date:  October 20th, 2022.  At 5:00 pm (Mexico time).

Title :  Parallel water photo-oxidation reaction pathways in hematite photoanodes: implications for solar fuel production

Abstract : 

Water photo-oxidation on stable metal-oxide photoanodes presents a critical challenge for solar fuel production. This reaction is widely considered to proceed in a sequential pathway with four stepwise hydroxide-coupled hole transfer steps. We studied experimentally the potentiodynamic discharge characteristics of hematite photoanodes under water photo-oxidation conditions. From an unexpected observation was deduced that the discharge proceeds in a parallel pathway, instead of a sequential one, suggesting the same for the reverse reaction that leads to water photo-oxidation. We derived a theoretical criterion with a kinetic model, which is able to explain the unexpected observation. The prevalence of parallel pathways fundamentally broadens the current paradigm of the water photo-oxidation reaction mechanism, and it may inspire new strategies to reduce the high overpotential of this reaction so as to enhance the efficiency of solar fuel production

Youtube link :  https://youtu.be/uE_gBMekI_Q