The Synergy Between Metal Facet And Oxide Support Facet For Enhanced Photocatalytic Performance

Designing new photocatalytic materials with improved photo-conversion efficiencies is a promising route to alleviate the environmental issues and energy crisis.As a type of promising nanomaterials,metal-oxide hybrid nanostructures are considered as favorable photocatalysts as they can efficiently promote the separation of electron-hole pairs.It has been demonstrated that the photocatalytic properties of hybrid nanomaterials can be improved by empolying different metals or semiconductors,and tuning the particle size,nanostructure and loading amount.Despite the success in the improvement of photocatalytic performance,the efficiency of photocatalysts is too low to be applied practically.Hence,it is of essential importance to find some new mechanisms or new tuning parameters that can significantly improve the catalytic performance of photocatalysts from both fundamental and practical perspectives.In this dissertation,we investigated the relationship between photocatalytic performance and crystal facet,a significant parameter that has been ignored in composite nanostructures.The specific research work including:1.The facet-selective deposition of metal nanoparticles on Co₃O₄ crystals was demonstrated.Through a photo-assisted method,metal nanoparticles were selectively deposited on the{111}facets of Co₃O₄ crystals.Further exploration indicated that the driving force for the selective deposition is the intrinsic charge separation between different facets.The Schottky barrier formed near the interface of Au and Co₃O₄promoted the spatial separation of electron-hole pairs,remarkably improving photocatalytic performance in the water oxidation reaction.2.On the basis of first-principle calculations,we expect that when Pd nanoparticles with exposed?001?facets were supported on the TiO₂?001?facets,the photocatalytic performance of Pd nanoparticles can be dramatically promoted.Such theoretical prediction has then been further verified by the experimental observations in which the Pd?100?-TiO₂?001?composites exhibit the highest catalytic performance toward the activation of oxygen among all the other shaped hybrid nanostructures.Our work suggests that there is a synergetic effect between the metal facet and oxide support facet,which may act as a new tuning parameter and play an important role in improving the photocatalytic performance.