This idea is not new, but until now scientists have focused on trying to mimic or modify the molecules directly involved in splitting hydrogen. “We’d like to adopt an entirely different concept, to mimic photosynthesis by copying the elaborate architectures of green leaves,” says Tongxiang Fan of The State Key Laboratory of Metal Matrix Composites at Shanghai Jiao Tong University, China.
In the experiment, Fan and his team used several types of leaves as a template, including the grape-leaved anemone (Anemone vitifolia). For the beginning, they treated the leaves with diluted hydrochloric acid, allowing them to replace magnesium atoms.
Then, they burned the remaining plant material at a temperature of 500 °C and ultimately the scientists were able to retain a crystallised titanium dioxide framework plus many of the leaves’ natural structures.
Finally, the researchers found that leaves possess lens-like cells on the surface, being capable of capturing light from almost any angle. Besides this, they have found that structures like thykaloids measure only 10 nanometres in thickness. Unlike the present titanium dioxide, artificial leaves are more efficient, absorbing more than twice as much light, and gave off more than three times as much hydrogen.