Unveiling Dynamic Structure and Bond Evolutions in BiOIO3 Photocatalysts during CO2 Reduction.

We have established a correlation between photocatalytic activity and dynamic structure/bond evolutions of BiOIO3-based photocatalysts during CO2 reduction by combining operando X-ray diffraction with photoelectron spectroscopy. More specifically, the selective photo-deposition of PtOx species on BiOIO3 (010) facets could effectively promote the electron enrichment on Bi active sites of (100) facets for facilitating the adsorption/activation of CO2 molecules, leading to the formation of Bi sites with high oxidation state and the shrink of crystalline structures. With introducing light irradiation to drive CO2 reduction, the Bi active sites with high oxidation states transformed into normal Bi3+ 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 PtOx-BiOIO3 (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 BiOIO3 (70.3 μmol g-1•h-1) samples. This work provides new insights to correlate the intrinsically dynamic structure/bond evolutions with CO2 reduction activity, which may help to guide future photocatalyst design.