Facile microwave-assisted synthesis and effective photocatalytic hydrogen generation of Zn2GeO4 with different morphology

Abstract

Single-crystalline hexagonal prism Zn₂GeO₄ nanorods and hierarchical Zn₂GeO₄ microspheres have been successfully synthesized via a facile microwave-assisted solution-phase approach. The as-prepared samples were characterized by XRD, SEM, TEM, HRTEM and UV-vis diffuse reflectance spectroscopy. The hierarchical Zn₂GeO₄ microspheres were found to be constructed of randomly aggregated nanorods which have dimensions of about 50 nm in length and 20 nm in width. Such rhombohedral phase Zn₂GeO₄ nanorods were found to be 10–20 nm in diameter and ∼200 nm in length. Some influencing factors such as the reaction time, temperature, and the urea were revealed to play crucial roles in the formation of Zn₂GeO₄ photocatalysts. A possible growth mechanism was proposed based on the experimental results. The rhombohedral phase Zn₂GeO₄ nanorods exhibited superior photocatalytic activities for the photocatalytic decomposition of water–methanol solution to hydrogen under UV irradiation.