A Z-scheme Fe2O3/g-C3N4 heterojunction for carbon dioxide to hydrocarbon fuel under visible illuminance.

Graphitic carbon nitride (g-C3N4) is a well-known semiconductor in the photocatalyst which absorbs in the visible region. Ferric oxide (Fe2O3) provides the necessary electron to the valence band of g-C3N4 to refill the deficiency. This system shows the Z-scheme mechanism of the transfer of electrons from the conduction band of Fe2O3 to the valence band of g-C3N4 to reduce the molecular CO2 into the hydrocarbon fuel. The methanol yield obtained was 1768 μmol/g cat. within 24 h in the presence of visible light. The yield of methanol obtained by 15%Fe2O3/g-C3N4 was high than that obtained with g-C3N4 and Fe2O3 under a similar reaction condition. The photocatalysts were characterized by HR-TEM, BET, XPS, XRD, FTIR, TGA-DTA, ICP-AES, UV-vis, Photoluminescence spectroscopy, and Raman spectroscopy. The photocatalyst was highly stable with no leaching and showed nearly constant activity up to five recycling runs.