Influence of Nb2O5 crystal structure on photocatalytic efficiency

[Display omitted] •Microwave-assisted method is suitable for obtaining Nb2O5 at low temperatures.•The increase in temperature changes the crystalline phase of the material.•Controlling the growth of the structure influences the photocatalytic response.•Nb2O5 without heat treatment is more effective than Nb2O5 submitted a heat treatment. This work demonstrates the application of crystalline Nb2O5 powders with different phases as photocatalysts in the degradation of Rhodamine B (RhB). The crystalline structure and the corresponding surface area of Nb2O5 changed with an increase in the heat-treatment temperature, leading to different photocatalytic activities. Thus, for Nb2O5 with low crystallinity, the total degradation of RhB on pseudohexagonal Nb2O5 is 97%, whereas that on orthorhombic Nb2O5 is 57%. The degradation products of RhB were identified from the results of high-performance liquid chromatography, mass spectrometry, and total organic content analysis, and the possible photocatalytic degradation pathways are proposed.