Green fabrication of La-doped NaTaO3 via H2O2 assisted sol-gel route for photocatalytic hydrogen production

摘要

Crystalline NaTaO3 nanoparticles doped with different concentrations of La~(3+) have been synthesized via a H2O2-assisted sol-gel route, in this reaction, TaCl5 is dissolved in aqueous H2O2 solution to form a stable transparent Ta-peroxo complex solution. The formation of tantalum-peroxo complexes and their chelation by citric acid enables a better control of crystal growth. X-ray diffraction and scanning/transmission electron microscopy provide useful information about crystallinity and morphology of the samples. The substitution of La~(3+) ions in the NaTaO3 lattice is verified by crystallographic simulation (CaRIne Crystallography version 3.1). These results indicate La~(3+) ions occupy the Na~+ ions sites, which agrees very well with the experimental data. The optimal content of La~(3+) ions effectively increases crystallinity without agglomeration, contributing to efficient charge separation and preventing recombination between pho-togenerated electrons and holes. The highest photocatalytic H2 production of 1.43 mmol h~(-1) is obtained for a 2.0mol% La-doped NaTaO3 sample. The NaTaO3 nanoparticles produced using this facile, environmentally friendly 'green process' have better crystallinity, smaller size and higher photocatalytic activity.