Continuous Tuning of Au-Cu O Janus Nanostructures for Efficient Charge Separation.

In photocatalysis, the Schottky barrier in metal-semiconductor hybrids is known to promote charge separation, but a core-shell structure always leads to a charge build-up and eventually shuts off the photocurrent. Here, we show that Au-Cu O hybrid nanostructures can be continuously tuned, particularly when the Cu O domains are single-crystalline. This is in contrast to the conventional systems, where the hybrid configuration is mainly determined by the choice of materials. The distal separation of the Au-Cu O domains in Janus nanostructures leads to enhanced charge separation and a large improvement of the photocurrent. The activity of the Au-Cu O Janus structures is 5 times higher than that of the core-shell structure, and 10 times higher than that of the neat Cu O nanocubes. The continuous structural tuning allows to study the structure-property relationship and an optimization of the photocatalytic performance.