Targeted design of organic Janus particles for improved photocatalytic hydrogen evolution.

Organic bulk heterojunction particles are decorated in a well-controlled way with metals by using light-assisted bipolar electrodeposition to yield Janus particles. Their asymmetric character leads to significantly enhanced photocatalytic hydrogen evolution reaction. The organic particles are first synthesized miniemulsion, tuning their size by carefully controlling various preparation parameters. Subsequently, the synergistic effect of an electric field and light is explored for the site-selective bipolar electrochemical deposition of different metals (Pt, Au or Pd). Photocatalytic tests reveal that in the case of platinum, the resulting Janus particles significantly outperform particles randomly covered with metal, as well as unmodified particles, showing an increase in hydrogen evolution efficiency by up to 500%. This superior performance is attributed to an enhanced charge carrier separation in the Janus structure, where Pt, confined at one side, facilitates more efficient electron shuttling and transfer. This work constitutes the first study reporting a promising approach for designing novel metal-organic Janus particles to boost photocatalytic hydrogen evolution and opens up new perspectives for optimizing the design of various other hybrid systems for sustainable energy conversion.