Visible Light Driven Photocatalytic Hydrogen Evolution by Lanthanum and Carbon-co-Doped NaTaO₃ Photocatalyst

Abstract

Lanthanum and carbon co-doped sodium tantalum oxide, La-C-NaTaO3, are prepared by incorporating lanthanum and carbon into NaTaO3 cluster via a sol-gel technique using a sucrose as carbon source. The La-C-NaTaO3 prepared sample is calcined at a temperature of 700 °C. Effects of carbon contents on the crystal, shape, optical absorption response and activity of hydrogen production of the sample are evaluated. The crystal of La-C-NaTaO3 is characterized by XRD analysis. The results show that the XRD pattern of the La C co-doped NaTaO3 is found to be crystalline phase with monoclinic structure. From the analysis of SEM images, the particle size of the prepared powder is about 40-200 nm. The optical response is examined by diffuse reflectance spectra (DRS). It is depicted that the absorption edge of La-C-NaTaO3 crystalline shift to higher wavelength. The extension to the visible light absorption edge became drastic with increasing carbon content in the sample. The photocatalytic activity of La-C-NaTaO3 is examined from water-methanol aqueous solution under visible light irradiation. It is found that the photocatalytic activity of La-C-NaTaO3 depend strongly on the doping content of C, and sample La-C-NaTaO3 shows the highest photocatalytic activity for the water reduction. The optimum amounts of carbon to maximize the hydrogen evolution rate is to be 2.5 mol %. The La-C-NaTaO3 catalyst has high activity of H2 evolution of 40.0 [μmol h-1] and long time stability under visible-light irradiation, suggesting a promising utilization of such photocatalyst. La C co-doped NaTaO3 photocatalyst can be developed further in order to produce hydrogen as a green energy.

Coconut husk ash as heterogenous catalyst for biodiesel production from cerbera manghas seed oil

“…Energy and environmental problems elevated by the usage and potential depletion of fossil fuels stimulate research on the new energy sources [1][2][3][4][5][6]. The increase in population and industrial development has accelerated the exploration of renewable clean energy resources such as hydrogen energy [7][8], solar energy [9][10], and biodiesel [11].…”

Pt nanoparticle on La0.02Na0.98TaO3 catalyst for hydrogen evolution from glycerol aqueous solution

“…The La0.02Na0.98TaO3 nanocatalyst was prepared according to the procedure that we reported previously [7]. The starting materials for the sol-gel synthesis were TaCl5 (Acros Organics; 99.9%), NaOH (Acros Organics; 99.9%), and 2.0 mol % of La(NO3)2.3H2O (Acros Organics; 99.9%).…”

“…The photocatalytic activity of La-doped NaTaO3 is significantly enhanced in the presence of a co-catalyst deposited on its surface [4][5][6]. Some researchers have collected such metals as Pd, NiO, Rh, loaded on the photocatalyst surfaces to serve as the co-catalyst [7]. Among the noble metals, Pt has found to be more effective, and they act as co-catalyst for the hydrogen evolution, by reducing the activation energy of water reduction.…”

Hydrogen production from water-glucose solution over NiO/La-NaTaO3 photocatalyst

“…The addition of doping or strange substance into NaTaO3 crystal structure can narrow band gab, increase crystallinity and smaller particle sizes, thus increasing the production level of hydrogen. Furthermore, the structure of the crystal photocatalyst also affecting photocatalysts band gap [8][9][10][11]. However, the efficiency of photocatalytic hydrogen evolution is in general very low due to the recombination of the photoinduced electron and hole, and the back reaction of H2 and O2.…”