Despite the enormous attention paid to cobalt oxide materials as efficient water splitting electrocatalysts, a deep understanding of their activity discrepancy is still elusive. In this work, we showed that stabilization of the internally generated oxygen evolution reaction (OER) active phase (oxyhydroxide) is crucial for ZnCoO electrocatalysts. A systematic evaluation of the bulk and nanostructured ZnCoO system concomitant with nanostructured CoO showed that leaching of Zn is the driving force behind the near-surface transformation to the oxyhydroxide phase.
View Article and Find Full Text PDFA thermal reaction route that induces grain fracture instead of grain growth is devised and developed as a top-down approach to prepare nanostructured oxides from bulk solids. This novel synthesis approach, referred to as the sequential oxygen-nitrogen exchange (SONE) reaction, exploits the reversible anion exchange between oxygen and nitrogen in oxides that is driven by a simple two-step thermal treatment in ammonia and air. Internal stress developed by significant structural rearrangement via the formation of (oxy)nitride and the creation of oxygen vacancies and their subsequent combination into nanopores transforms bulk solid oxides into nanostructured oxides.
View Article and Find Full Text PDFA recent surge of interest in metal (oxy)nitride materials for energy storage devices has given rise to the rapid development of various nanostructuring strategies for these materials. In supercapacitor applications, early transition metal (oxy)nitrides have been extensively explored, among which titanium oxynitride stands out due to its great potential for charge storage. Despite recent advances in supercapacitors based on titanium oxynitride, many underlying factors governing their capacitive performance remain elusive.
View Article and Find Full Text PDFWhile zinc oxide (ZnO) with a mesoporous network has long been explored for adsorption of dyes and as an electron-transporting medium in dye-sensitized solar cells (DSSCs), the performance of ZnO-based DSSCs remains unsatisfactory. Despite the importance of understanding the surface characteristics of ZnO in DSSC applications, most of the studies relevant to ZnO-based DSSCs are focused on the synthesis of unique nanostructures of ZnO. In this study, we not only introduce a novel disk-shaped ZnO nanostructure, but also provide insight into the distinctive surface properties of ZnO and its influence on DSSC performance.
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