Atomically Thin Zn2GeO4 Nanoribbons: Facile Synthesis and Selective Photocatalytic CO2 Reduction toward CO

Atomically thin Zn2GeO4 (ZGO) nanoribbons exclusively exposing the {100} facet of similar to 1 nm in thickness were successfully prepared via convenient photo-oxidation exfolia-tion of the ZGO-ethylenediamine hybrid at room temperature. The ultrathin ZGO nanoribbons [abbreviated as ZGO(100)] exhibit efficient and dominantly selective CO2 photoreduction performance into CO with the evolution yield of up to 20.81 /mol g-1 h-1 in the presence of water vapor, in much contrast to only CH4 production of 0.67 /mol g-1 h-1 for (010), exposing the thick ZGO nanobelts reported previously. The atomically thin structure of ZGO(100) shortens the migration distance of charge carriers onto the surface from the interior and allows more electrons to survive and accumulate on the surface, thus benefiting the activation and reduction of CO2. The density function theory calculation reveals that the formed CO* is inclined to escape from the exclusively exposed {100} facet of the ultrathin ZGO nanoribbon rather than be further protonated to derive CHO*, a vital intermediate for CH4 formation, leading ZGO(100) to be an ideal platform for catalytically selective CO production. This work would not only enrich atomically thin catalyst materials but also render a new platform for the development of ternary semiconductors with outstanding performance in CO2 photoconversion.