A photocatalyst sheet consisting of doped La₅Ti₂Cu_0.9Ag_0.1O₇S₅ as a hydrogen evolution photocatalyst (HEP), BiVO₄ as an oxygen evolution photocatalyst (OEP), and Au as a conductor layer exhibits a solar-to-hydrogen energy conversion efficiency (STH) of 0.67% at 4 kPa in Z-scheme overall water splitting (ZOWS). However, the photocatalyst sheet loses its activity at elevated pressure due to backward reactions. Here, we show that this loss of activity can be suppressed by coating the sheet with amorphous SiO₂ layer. In addition, the SiO₂ coating maintained its performance at elevated temperatures, unlike the widely used amorphous TiO₂ coating, and exhibited an STH of 0.41% at 90 kPa and 333 K. The results of the present study demonstrate the ability to functionalize photocatalyst sheets of narrow-band-gap materials prone to backward reactions, allowing their use in outdoor environments, and paves the way for practical solar hydrogen production.

由作为析氢光催化剂(HEP)的掺杂La ₅ Ti ₂ Cu _0.9 Ag _0.1 O ₇ S ₅、作为析氧光催化剂(OEP)的BiVO ₄和作为导体层的Au组成的光催化剂片表现出太阳能-到-在 Z 型整体水分解 (ZOWS) 中，4 kPa 下的氢能转换效率 (STH) 为 0.67%。然而，光催化剂片在高压下由于逆向反应而失去活性。_{在这里，我们表明，可以通过在片材上涂覆无定形 SiO 2}层来抑制这种活性损失。此外，SiO _{2与广泛使用的无定形 TiO 2}涂层不同，该涂层在高温下保持其性能，并且在 90 kPa 和 333 K 下表现出 0.41% 的 STH。本研究的结果表明能够对窄带隙光催化剂片进行功能化易于发生逆反应的材料，允许它们在室外环境中使用，并为实用的太阳能制氢铺平了道路。