Triple-Shelled Co-VSex Hollow Nanocages as Superior Bifunctional Electrode Materials for Efficient Pt-Free Dye-Sensitized Solar Cells and Hydrogen Evolution Reactions

摘要： Complex nanostructures with distinct spatial architectures and more active sites hold broad prospects in new energy conversion fields. Herein, a facile strategy was carried out to construct triple-shelled Co-VSex nanocages, starting via an ion-exchange process about Co-based zeolitic imidazolate framework-67 (ZIF-67) nanopolyhedrons and VO3?, followed by the formation of triple-shelled Co-VSex hollow nanocages during the process of rising the solvothermal temperature under the assistance of SeO32?. Meanwhile, triple-shelled Co-VSx and yolk-double shell Co-VOx nanocages were fabricated as references by a similar process. Benefiting from the larger surface areas and more electrolyte adsorption sites, the triple-shelled Co-VSex nanocages exhibited excellent electrocatalytic performances when applied as the electrochemical catalysts for dye-sensitized solar cell (DSSC) and hydrogen evolution reaction (HER). More concretely, the DSSC based on Co-VSex counter electrode (CE) showed outstanding power conversion efficiency of 9.68% when Pt counterpart was 8.46%. Moreover, Co-VSex electrocatalyst exhibited prominent HER performance with a low onset overpotential of 40 mV and a small Tafel slope of 39.1 mV dec?1 in acid solution.