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

Abstract

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.

Significant Acceleration of Photocatalytic CO2 Reduction to HCOOH at Gas-Liquid Interface

“…Numerous scientific efforts are devoted to fully take advantage of CO2 by developing highly efficient photocatalysts that show good CO2RR performance [33][34][35][36][37] . It is generally accepted that a nano-sized catalyst with good dispersion is highly desirable for the reaction that occurs in the aqueous media 15,16,38,39 . Following the above spirits, we picked three nano-sized catalysts with high photocatalytic CO2 reduction activity from the literature for further microdroplet experiments.…”

“…Over the last decades, while substantial attention and efforts have been focused on the tailored design of highly-efficient photocatalysts to improve the charge carrier separation dynamics for CO2RR 11,[14][15][16] , the low solubility of CO2 in water and its restricted diffusion coefficient, which greatly limited the catalytic performance and inevitably hinder its practical application. Recently, triphase photocatalysis is considered a potential candidate for addressing the mass-transfer limitation during CO2 photoreduction [11][12][13] mainly due to its efficient mass transfer, that is able to quickly delivered CO2 to the surface of the catalyst.…”

Anin situ-fabricated p-Co3O4@n-ZnO surface heterojunction photocatalyst for solar-to-fuel conversion of CO2

“…As a traditional photocatalyst with commercial prospects, the n-type semiconductor ZnO has the advantages of being cheap, earth-abundant and non-toxic. 10,11 Due to the suitable energy band position and high chemical stability, ZnO has always been used as a basic material to construct p-n heterojunction photocatalysts. [11][12][13][14][15] Although the separation of electron-hole pairs is promoted, the active site density and photo utilization are not improved due to the bulk-bulk phase of the muchreported ZnO based p-n heterojunction photocatalysts.…”

Recent advances in solar‐driven CO2 reduction over g‐C3N4‐based photocatalysts

“…Carbon cycle feedback is critical to maintaining global carbon balance 1,2 . However, owing to the anthropogenic emission, CO 2 level in the atmosphere significantly increases, which has exceeded the natural sequestration capacity and breaks the carbon cycle balance, thus leading to climate warming 3–6 . What's worse, the large‐scale utilization of fossil fuels causes energy shortage and environmental pollutant crisis 7–9 …”