Simultaneously efficient light absorption and charge transport of phosphate and oxygen-vacancy confined in bismuth tungstate atomic layers triggering robust solar CO2 reduction

Abstract The fundamental catalytic limitations for the photoreduction of CO 2 still remain: low efficiency, poor charge transport and short lifetime of catalysts. To address the critical challenges, an efficient strategy based on spatial location engineering of phosphate (PO 4 ) and oxygen-vacancy (V o ) confined in Bi 2 WO 6 (BWO) atomic layers is employed to establish and explore an intimate functional link between the electronic structures and activities of V o -PO 4 -BWO layers. Both theoretical and experimental results reveal, the V o -PO 4 -BWO layers not only narrow the band gap from the UV to visible-light region but also reduce the resistance. The time-resolved photoluminescence decay spectra exhibit the increasing carrier lifetime for V o -PO 4 -BWO layers, indicating the improved charge separation and transfer efficiency. As expected, the V o -PO 4 -BWO layers with the simultaneously efficient light absorption and charge transport properties achieve much higher methanol formation rate of 157 μmol g -1 h -1 , over 2 and 262 times larger than that of BWO atomic layers and bulk BWO. This work may reveal that the light absorption and spatial charge transport over atomic layers could benefit CO 2 conversion and shed light on the design principles of efficient photocatalysts towards solar conversion applications.