Sustained CO2-photoreduction activity and high selectivity over Mn, C-codoped ZnO core-triple shell hollow spheres

Solar conversion of CO2 into energy-rich products is one of the sustainable solutions to lessen the global energy shortage and environmental crisis. Pitifully, it is still challenging to attain reliable and affordable CO2 conversion. Herein, we demonstrate a facile one-pot approach to design core-triple shell Mn, C-codoped ZnO hollow spheres as efficient photocatalysts for CO2 reduction. The Mn ions, with switchable valence states, function as “ionized cocatalyst” to promote the CO2 adsorption and light harvesting of the system. Besides, they can capture photogenerated electrons from the conduction band of ZnO and provide the electrons for CO2 reduction. This process is continuous due to the switchable valence states of Mn ions. Benefiting from such unique features, the prepared photocatalysts demonstrated fairly good CO2 conversion performance. This work is endeavoured to shed light on the role of ionized cocatalyst towards sustainable energy production.

Fabrication of Ag/ZnO hollow nanospheres and cubic TiO2/ZnO heterojunction photocatalysts for RhB degradation

ZnO nanomaterials with the stereochemical structure were becoming a research focus in the scope of photocatalytic materials, but the ZnO was sensitive to UV light rather than the solar light source, which considerably prohibited its extended application. ZnO nanomaterials coupled with other nanomaterials could generate the alternative composite heterojunction nanomaterials to promote the photocatalytic activity. Herein, we reported two facile and feasible synthesis methods to fabricate TiO2/ZnO cube nanocomposites and Ag/ZnO hollow spheres by hydrothermal reaction and chemical deposition, respectively. In this regard, these composited nanomaterials have been successfully fabricated with high purities, good morphology, and crystal structure. Noticeably, in contrast with TiO2/ZnO and Ag/ZnO bulk nanocomposites, the Ag/ZnO hollow spheres could offer the higher activity for RhB degradation under the visible light. Moreover, the photocatalytic performance of Ag/ZnO for RhB degradation could be improved synergistically, and the effect of RhB degradation was highest when the Ag mass ratio was modulated at 10% in the sample. Furthermore, it remained a high photocatalytic efficiency even after four cycles. This protocol provided an approvable approach to fabricate efficient photocatalysts with persistent photostability in the wastewater treatment process.

Sustained CO2-photoreduction activity and high selectivity over C, Mn-codoped ZnO core-triple shell hollow spheres

Solar conversion of CO2 into energy-rich products is one of the sustainable solutions to lessen the global energy shortage and environmental crisis. Pitifully, it is still challenging to attain reliable and affordable CO2 conversion. Herein, we demonstrate a facile one-pot approach to design core-triple shell Mn, C-codoped ZnO hollow spheres as efficient photocatalysts for CO2 reduction. The Mn ions, with switchable valance states, function as “ionized cocatalyst” to promote the CO2 adsorption and light harvesting of the system. Besides, they can capture photogenerated electrons from the conduction band of ZnO and provide the electrons for CO2 reduction. This process is continuous due to the switchable valence states of Mn ions. Benefiting from such unique features, the prepared photocatalysts demonstrated remarkably selective CO2 conversion into CH3OH (yielding ten times higher than that of commercial ZnO). This work is endeavoured to shed light on the role of ionized cocatalyst towards sustainable energy production.