Enriching electrochemical and visible light photodegradation performance of nickel doped indium sulfide nanocrystals via hydrothermal route

Nanostructures of indium sulfide and nickel doped indium sulfide were analyzed using XRD, FTIR, FE-SEM, EDX, UV–Vis DRS, PL, and XPS. XRD reveals the crystallinity, orthorhombic structure of the sample and the average crystallite size has risen from 10 to 19 nm. The accumulation of nickel in varying proportions with In2S3 causes the absorption bands to shift gradually and the peaks to be sharpen in the FTIR spectrum, the irregularly shaped agglomeration and well-dispersed nanoparticles to be observed as spherical-shaped structure using FE-SEM and the elemental composition to be confirmed in EDX. In the wavelength range of 300 nm to 1400 nm, UV–Vis DRS reveals the reflectance edges of both pure and doped samples. The optical band gap energy of pure In2S3 is 2.80 eV and it declines as nickel dopants are added from 2.70 eV to 2.66 eV and to 2.56 eV. PL spectra show the emission peaks of Ni-In2S3 nanoparticles are at 449 nm, 505 nm and 568 nm, the elemental composition is evaluated in detail using XPS, and the degradation efficiency of methylene blue is 85 % for Ni-In2S3 photocatalyst, which performs better than undoped In2S3 (82 %) under natural sunlight irradiation. Compared to nanoparticles of undoped In2S3, Ni-In2S3 improved photocatalytic activities for wastewater treatment and electrochemical performance for supercapacitor.