Photocatalysis has been widely explored to alleviate the high atmospheric CO 2 content by converting CO 2 into energy-rich fuels. Bi 2 WO 6 shows great potential in photocatalysis due to its high chemical stability, non-toxicity and appropriate band position. However, the CH 4 yield from CO 2 photoreduction over bulk Bi 2 WO 6 is relatively low ascribed to its single-component structure. Inspired by natural photosynthesis, Z-scheme system with photosystem I (PS I)-photosystem II (PS II) coupling via an electron mediator can improve charge separation and at the same time, renders large overpotential, attributed to the vectorial electron transfer from PS II to PS I. In this contribution, an all-solid-state Z-scheme photocatalyst that is composed of 2D Bi 2 WO 6 nanosheets coupled with WO 3 along with the incorporation of copper foil sheet as the electron mediator is designed to improve the CO 2 reduction efficiency. The Bi 2 WO 6 / Cu/WO 3 composite demonstrated a remarkable CH 4 yield of 8.80 μmol g À 1 catalyst over 8 hours of visible light illumination, which is superior to the Bi 2 WO 6 standalone.[a] Y.