Speaker
Description
In the 21st century, when we are facing an energy crisis as one of the major global problems, the idea developed in 1972 by Fujishima and Honda about the hydrogen production by solar-driven photoelectrochemical (PEC) water splitting using semiconductor (TiO2) as a photoanode is more popular than ever. It is known that crystalline defects can have a great impact on optical and electrical properties of a semiconductor used as a photoanode for PEC. Surface defects can improve absorption capacity while bulk defects, commonly oxygen vacancies, can act as recombination centers leading to the loss of photocatalytic efficiency. Thus, understanding the relationship between oxygen vacancies and (photo)electrocatalytic efficiency is important for successful application of semiconductor as a photoanode materials.
During the years, we have used different approaches to modify surface-to-bulk oxygen vacancies ratio in ZnO crystal structure. Amount and type of oxygen vacancies have been tailored employing different surfactants (PEO, CTAB, Pluronic F127, etc.) or graphene oxide as additive during microwave processing of Zn(OH)2 precipitate, as well as by additional annealing of prepared ZnO-based particles. To comprehend the influence of oxygen vacancies on (photo)electrocatalytic activity of ZnO-based particles, at first, their crystal structure, morphological, textural, and optical properties have been investigated in details, then (photo)electrocatalytic activity for both hydrogen and oxygen evolution reactions (HER and OER) have been tested in acidic and alkaline electrolytes using linear voltammetry. The influence of amount and type of oxygen vacancies on (photo)electrocatalytic activity have been discussed and correlated with charge separation and radiative recombination of photogenerated electron-hole pairs.
| Scientific Sections | Materials |
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