Development of Zinc Hydroxide as an Abundant and Universal Cocatalyst for the Selective Photocatalytic Conversion of CO2 by H2O. Issue 20 (28th July 2021) - Xu, Xuanwen
Abstract: Water splitting is always a strongly competitive reaction against the photocatalytic conversion of CO2 using H2 O as the electron donor over powder photocatalysts. At present, only Ag nanoparticles function as a universal cocatalyst for the activity and selectivity of CO2 conversion in this regard. Herein, abundant Zn(OH)2 is investigated over various typical powder photocatalysts and shows attractive universality in the enhancement of activity and selectivity toward CO evolution from CO2 . Taking ZnTa2 O6 as an example, the rate of formation of H2 was suppressed (from 32.8 to 5.8 μmol h −1 ), while the formation of CO was dramatically promoted (from 18.4 to 81.4 μmol h −1 ) with Zn(OH)2 as the cocatalyst. Zn ions dissolved in solution and an alkaline electrical double layer of the photocatalysts are proved to be important for the function of Zn(OH)2 . Abstract : A universal selectivity of CO evolution in photocatalytic conversion of CO2 by H2 O over powder photocatalysts can be achieved with Zn(OH)2 as the cocatalyst. Critical factors for the function of Zn(OH)2 are an alkaline electrical double layer surrounding the photocatalysts and dissolved Zn ions in the bulk reaction solution because an equilibrium between the Zn(OH)2 dot and dissolved Zn ions in the alkaline EDL needs to be established.