Unique Zinc Germanium Oxynitride Hyperbranched Nanostructures with Enhanced Visible‐Light Photocatalytic Activity for CO2 Reduction

Unique (Zn1+xGe)(N2Ox) hyperbranched nanostructures with rough surfaces were prepared by nitriding Zn2GeO4 bundles at 700 °C. In this process, the constituent smooth nanobelts of the Zn2GeO4 bundles are transformed into chains composed of nanoparticles; therefore, the (Zn1+xGe)(N2Ox) hyperbranched nanostructures have a lager specific surface area, which is twice that of the Zn2GeO4 precursor. Compared to reference (Zn1+xGe)(N2Ox) particles synthesized by a solid‐state reaction approach as well as (Zn1+xGe)(N2Ox) prepared by nitriding Zn2GeO4 nanorods at 700 °C for 6 h, the optimal hyperbranched (Zn1+xGe)(N2Ox) particles exhibit enhanced activity for the photoreduction of CO2 to CH4 under visible light due to their unique 3D hyperbranched nanostructure. A GaN–ZnO solid solution with a 3D microsphere structure can be obtained by a similar process. This work provides valuable information for the preparation of oxynitrides with high specific surface areas. Unique (Zn1+xGe)(N2Ox) hyperbranched nanostructures with rough surfaces, tailored by simply nitriding Zn2GeO4 bundles at 700 °C, exhibit enhanced activity toward the reduction of CO2 to CH4 under visible light due to their 3D hyperbranched nanostructure.