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. The distal arrangement of Au–Cu2O domains in the Janus structure promotes charge separation, leading to a five‐ and tenfold enhancement of the photocurrent of the Au@Cu2O core–shell structure and the neat Cu2O nanocubes, respectively.