Single-Step Production of a TiO2@MoS2 Heterostructure and Its Applications as a Supercapacitor Electrode and Photocatalyst for Reduction of Cr(VI) to Cr(III).

In this study, we have reported a one-step synthesis of a TiO2@MoS2 heterostructure. TiO2@MoS2 was synthesized using a facile and cost-effective method. The as-synthesized TiO2@MoS2 heterostructure was characterized by suitable spectroscopic techniques. The obtained TiO2@MoS2 was utilized as a supercapacitor electrode material. Electrochemical studies show that the TiO2@MoS2 heterostructure possesses a specific capacitance of 337 F/g at a current density of 1 A/g in an aqueous solution. Furthermore, an application as a photocatalyst for the photoreduction of toxic hexavalent chromium was reported for the first time. This heterostructure showed the photoreduction of Cr6+ to Cr3+ in 120 min with formic acid as a scavenger under direct sunlight. A plausible mechanism of photoreduction of Cr6+ to Cr3+ under natural sunlight irradiation using TiO2@MoS2 is proposed.

Preparation of CdS-TiO2-Based Palladium Heterogeneous Nanocatalyst by Solvothermal Route and Its Catalytic Activity for Reduction of Nitroaromatic Compounds.

In this study, bare CdS nanoparticles (NPs) were prepared by solvothermal method using CdCl2(3-methylbenzaldehyde thiosemicarbazone)2 as a single-source molecular precursor in the presence of ethylene glycol. Further, these CdS NPs were used for the preparation of binary (CdS-TiO2) and ternary (CdS-TiO2/Pd) heterogeneous nanocatalysts. Characterization of the as-prepared nanocatalysts has been carried out using different techniques such as powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy, and photoluminescence studies. The peak observed at 2θ = 39.5° in XRD confirms the successful doping of noble metal (Pd) on the surface of CdS-TiO2 nanocatalyst, which is well supported by Raman analysis. From FESEM and TEM analyses, mixed morphology has been observed and elemental composition was confirmed by energy-dispersive X-ray spectroscopy elemental mapping. Furthermore, the as-prepared bare CdS NPs, binary CdS-TiO2, and ternary CdS-TiO2/Pd heterogeneous nanocatalysts were used for the reductive transformation of various nitroaromatic compounds to their corresponding aromatic amines at room temperature. It has been observed that among all of the catalysts, ternary CdS-TiO2/Pd heterogeneous nanocatalyst has excellent catalytic property to reduce all nitroaromatic compounds in very short time span.

One-Pot Synthesis of Pd-Based Ternary Pd@CdS@TiO2 Nanoclusters via a Solvothermal Route and Their Catalytic Reduction Efficiency toward Toxic Hexavalent Chromium.

In this work, we report the synthesis of Pd-based ternary Pd@CdS@TiO2 nanocomposites using molecular precursors. This method is facile, less time-consuming, and cost-effective. This catalyst is prepared within 2 h by a solvothermal route using molecular precursors. Information about the phase, morphologies, elemental mapping, and composition of the nanocomposites was obtained using various characterization techniques. The catalytic activity of the as-prepared Pd-based ternary Pd@CdS@TiO2 nanocomposites exhibits effective reduction efficiency for the conversion of toxic Cr(VI) to Cr(III) using formic acid as a reducing agent within 5-7 min. To the best of our knowledge, this is the first report on Pd-based ternary Pd@CdS@TiO2 nanocomposites prepared by a solvothermal route and used as catalysts toward the reduction of hexavalent chromium at room temperature.