Carbon-conductor-based photocatalyst sheets fabricated by a facile filtration process for efficient, stable, and scalable water splitting

The use of Z-scheme photocatalyst sheets is a promising approach to efficient renewable hydrogen production via sunlight-driven water splitting using immobilized particulate photocatalysts. However, most existing systems are not scalable because of the use of costly vacuum and harmful calcination processes and conductors that are unstable and prone to back reactions. Here, we show that carbon-based electron conductors, incorporated by a facile filtration process, can overcome these problems. Z-scheme photocatalyst sheets consisting of cocatalyst-loaded Sm₂Ti₂O₅S₂ and BiVO₄ (which serve as a hydrogen evolution photocatalyst and an oxygen evolution photocatalyst, respectively, under visible light), bridged with carbon-based electron conductors, provide a solar-to-hydrogen energy conversion efficiency of 0.4%, despite the simplicity of fabrication and operation, and can evolve hydrogen and oxygen under photoexcitation at atmospheric pressure. This study provides a practical approach to realizing commercial-scale solar hydrogen production via Z-scheme photocatalytic water splitting.