Unveiling Dynamic Structure and Bond Evolutions in BiOIO 3 Photocatalysts during CO 2 Reduction.

We have established a correlation between photocatalytic activity and dynamic structure/bond evolutions of BiOIO 3 -based photocatalysts during CO 2 reduction by combining operando X-ray diffraction with photoelectron spectroscopy. More specifically, the selective photo-deposition of PtO x species on BiOIO 3 (010) facets could effectively promote the electron enrichment on Bi active sites of (100) facets for facilitating the adsorption/activation of CO 2 molecules, leading to the formation of Bi sites with high oxidation state and the shrink of crystalline structures. With introducing light irradiation to drive CO 2 reduction, the Bi active sites with high oxidation states transformed into normal Bi 3+ state, accompanying with the expansion of crystalline structures. Owing to the dynamic structure, bond, and chemical-state evolutions, a significant improvement of photocatalytic activity for CO evolution has been achieved on PtO x -BiOIO 3 (195.0 μmol g -1  ⋅ h -1 ), much higher than the pristine (61.9 μmol g -1  ⋅ h -1 ) as well as metal-Pt decorated BiOIO 3 (70.3 μmol g -1  ⋅ h -1 ) samples. This work provides new insights to correlate the intrinsically dynamic structure/bond evolutions with CO 2 reduction activity, which may help to guide future photocatalyst design.