Barium titanate photocatalysts with silver-manganese dual cocatalyst for carbon dioxide reduction with water.

Titanate photocatalysts with suitable cocatalysts are promising candidates for photocatalytic CO 2 reduction, with the use of water as an electron donor. Here, several barium titanates with various compositions were examined, and BaTi 4 O 9 (BT4) was found to be the best photocatalyst with the assistance of an Ag cocatalyst for photocatalytic CO 2 reduction to form CO. The photocatalytic activity was further enhanced by the use of MnO x as an additional cocatalyst to construct an Ag-MnO x /BT4 photocatalyst, where Ag and MnO x were selectively deposited at different facets on BT4 crystal and functioned as active sites for CO 2 reduction and water oxidation, respectively. As for the oxidative products from water, molecular oxygen (O 2 ) and hydrogen peroxide (H 2 O 2 ) were obtained.