Continuous Tuning of Au–Cu₂O 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–Cu₂O hybrid nanostructures can be continuously tuned, particularly when the Cu₂O 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–Cu₂O domains in Janus nanostructures leads to enhanced charge separation and a large improvement of the photocurrent. The activity of the Au–Cu₂O Janus structures is 5 times higher than that of the core–shell structure, and 10 times higher than that of the neat Cu₂O nanocubes. The continuous structural tuning allows to study the structure–property relationship and an optimization of the photocatalytic performance.