Dan Wang1

1, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, , China

To find practical techniques for manufacturing clean and sustainable energy is a globally demanding challenge due to the shortage of fossil fuels as well as the global climate changes. Solar water splitting directly to hydrogen and oxygen has become one of the most desirable methods for harvesting and conversion of solar energy into chemical energy.
Among various water splitting materials, metal oxide semiconductors are particularly appealing candidates for practical applications. Recently, in order to replace the noble metal to enhance hydrogen evolution performance, a variety of transition metal oxides and hydroxides are widely used as effective co-catalyst. In this work, we successfully synthesized multi-shelled heterostructural metal oxide hollow spheres by the sequential templating method. The advantages of our designed multi-shelled hollow spheres are as follows: 1) the porous structures enlarges the specific surface area, 2) a void cavity enables the solvent to access the reactive sites and enhances the matter transfer, 3) hollow structures enhances the light harvesting capability and 4) thin shells shorten the diffusion paths for photoexicited electrons and holes. These unique features of our designed morphology make it a promising candidate in solar water splitting. When tested as hydrogen evolution reaction materials for water splitting, the multi-shelled heterostructural metal oxide hollow spheres exhibited a higher oxygen evolution reaction rate and good stability, which are competitive among the TiO2 based photocatalysts. This work opens up a new method to enhance hydrogen evolution performance by structural design.