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The surfactant-assisted synthesis of tantalum oxide nanoparticles (Ta 2 O 5 ), its subsequent nitridation to form tantalum nitride (Ta 3 N 5 ), and the evaluation of the photoactivity of these nanoparticles, are presented. The surface, optical, and compositional characterization of the in-house synthesized photocatalysts indicate spherical nanoparticles with φ = 30 nm Ta 2 O 5 and φ = 30 nm Ta 3 N 5 with the latter photocatalysts showing absorbance onset at ∼ 630 nm. Photoelectrochemical analysis of the various photocatalyst films using chronoamperometry, linear sweep voltammetry, and impedance measurements attribute an improved photoactivity with the in-house catalysts to better charge generation, transport, and utilization. Initial results using Ta 2 O 5 and Ta 3 N 5 demonstrate photocatalytic activity toward conversion of colored pollutants.

A simplified ammonolysis method for synthesizing single phase TaON nanoparticles is presented and the resulting photoelectrochemical properties are compared and contrasted with as-synthesized Ta2O5 and Ta3N5. The protocol for partial nitridation of Ta2O5 (synthesis of TaON) offers a straightforward simplification over existing methods. Moreover, the present protocol offers extreme reproducibility and enhanced chemical safety. The morphological characterization of the as-synthesized photocatalysts indicate spherical nanoparticles with sizes 30, 40, and 30 nm Ta2O5, TaON, and Ta3N5 with the absorbance onset at ~320 nm, 580 nm, and 630 nm respectively. The photoactivity of the catalysts has been examined for the degradation of a representative cationic dye methylene blue (MB) using xenon light. Subsequent nitridation of Ta2O5 yields significant increment in the conversion (ζ: Ta2O5 < TaON < Ta3N5) mainly attributable to the defect-facilitated adsorption of MB on the catalyst surface and bandgap lowering of catalysts with Ta3N5 showing > 95% ζ for a lower (0.1 g) loading and with a lamp with lower Ultraviolet (UV) content. Improved Photoelectrochemical performance is noted after a series of chronoamperometry (J/t), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) measurements. Finally, stability experiments performed using recovered and treated photocatalyst show no loss of photoactivity, suggesting the photocatalysts can be successfully recycled.