Shape- and size-controlled nanomaterials for artificial photosynthesis

Nanomaterials with various shapes and sizes have been developed to mimic functions of photosynthesis in which solar energy conversion is achieved by using nanosized proteins with controlled shapes and sizes. Artificial photosynthesis consists of light-harvesting and charge-separation processes together with catalytic units of water oxidation and reduction. Nanosized mesoporous silica-alumina was utilized to encapsulate organic charge-separation molecules inside the nanospace to elongate the lifetimes of the charge-separated states, as observed in the photosynthetic reaction centers. Metal nanoparticles with controlled shapes and sizes have also been utilized as efficient catalysts for photocatalytic hydrogen evolution from water with reductants by using electron donor-acceptor organic molecules as photocatalysts. The control of the shape and size of metal nanoparticles plays a very important role in achieving high catalytic performance in catalytic hydrogen evolution in water reduction and also in catalytic oxygen evolution in water oxidation. Taking control: The focus is on the control of shape and size of nanomaterials utilized in the development of light-harvesting and charge-separation nanomaterials as well as nanosized catalysts for water oxidation and reduction in artificial photosynthesis. The efficiency of metal and metal-oxide nanoparticle catalysts can be improved by controlling the shapes and sizes of the nanoparticles. Shape- and size-controlled nanoparticles aimed to be utilized in artificial photosynthesis are reviewed.