Peer Review #1 of "Hydrothermal synthesis of carbon and sulfur mono-doped sodium tantalates (v0.1)"

Abstract

A set of experiments was conducted to synthesize doped and undoped sodium tantalates with carbon and sulfur in energy efficient single-step hydrothermal process. Undoped sodium tantalate nanocubes were synthesized at 140 o C and doped one at 180 o C for 12 hours in rich alkaline atmosphere. The sizes of undoped, carbon-doped, and sulfur-doped sodium tantalate nanocubes were 38 nm, 45 nm, and 40 nm, respectively. The morphological, elemental, compositional, structural, thermal, and photophysical properties of as-synthesized doped and undoped sodium tantalate (NaTaO 3 ) were characterized using scanning electron microscope (SEM), energy dispersive x-ray spectroscope (EDS), Raman spectroscopy, X-ray powder diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared spectrophotometer (FTIR), and UV-vis spectrophotometer. The sulfur doped NaTaO 3 shows a higher photocatalytic activity in degradation of methylene blue than carbon doped and the undoped NaTaO 3 . The band gaps of undoped NaTaO 3 , carbon doped c-NaTaO 3 , and sulfur doped s-NaTaO 3 were calculated to be 3.94 eV, 3.8 eV, and 3.52 eV, respectively using Tauc plot.