Ch4n2s

In this study, Ag-doped TiO₂ nanoparticles were prepared using several reagents, including titanium tetra isopropoxide (C₁₂H₂₈O₄Ti, 97%, Sigma-Aldrich, St. Louis, MO, USA), silver nitrate (AgNO₃, 99%, Merck, Boston, MA, USA), glacial acetic acid (CH₃COOH, 99%, Merck), nitric acid (HNO₃, 69%, Merck), and absolute ethanol (C₂H₅OH, Sigma-Aldrich). Moreover, analytical-grade urea (CH₄N₂O, 99.5%, Merck) and thiourea (CH₄N₂S, 99%, Merck) were used to synthesize g-C₃N₄ nanosheets. Fabricated Ag–TiO₂ nanoparticles and g-C₃N₄ nanosheets were used to synthesize heterostructured g-C₃N₄/Ag–TiO₂ nanocomposites. All the chemicals and reagents were used as received without further purification. Distilled water was used in all experiments.

Pristine g-C₃N₄ was synthesized by a thermal polycondensation method. The precursor, thiourea (30 g) (CH₄N₂S, ≥99%, supplied by Sigma-Aldrich Korea, South Korea), was placed in a crucible covered with aluminum foil and heated to 550 °C for 4 h (ramping rate = 5 °C/min) in a muffle furnace, using air as the atmosphere. The as-synthesized bulk g-C₃N₄ sample was named CN.
One gram of CN powder was dissolved in 100 mL of DI water and then sonicated for 2 h at room temperature. The 150 mL Teflon^™ autoclave containing the CN-180-x samples (x = 3, 6, or 9 h where x was the hydrothermal period) was heated in an oven to 180 °C (ramping rate = 5 °C/min). In comparison with the CN-180-6, the CN-200-6 was synthesized in 6 h at 200 °C. The resulting materials were repeatedly rinsed with DI water after cooling to room temperature before being freeze-dried for the photocatalytic activity test and further characterization. The schematic procedure for CN and catalysts synthesis was illustrated Figure 1.

Reagent grade chemicals of CoCl₂.6H₂O and CH₄N₂S were purchased from Sigma Aldrich-India for the preparation of nanostructured CoS. For the fabrication of asymmetric supercapacitor activated carbon (AC), carbon felt and KOH were purchased from Alfa Aesar, India. TiO₂ paste (P25-Degussa), N719 dye [Di-tetrabutylammonium cis-bis (isothiocyanato) bis(2,2′-bipyridyl-4,4′-dicarboxylato) ruthenium(II)] and FTO substrate (~7 Ω/cm²) of Sigma Aldrich were purchased for the construction of dye-sensitized solar cells. Standard platinum counter electrode and LiI electrolyte were procured from Dyesol, Australia for the fabrication of DSSC.

The MoS₂@rGO composite nanostructures were synthesized
by using the hydrothermal technique. Initially, the reduced graphene
oxide (rGO) nanosheets were synthesized via the microwave-assisted
reduction procedure as previously reported.^{28 (link)} Typically, graphene oxide powder was irradiated with 1 kW inside
argon (Ar) plasma for 3 min at a pressure of 10 mbar in a quartz flask
(1 L volume) connected to a vacuum pump and an argon mass flow meter
(200 mL/min), followed by cooling to room temperature under Ar gas,
washing the rGO samples with a solvent, and finally drying overnight
at 80 °C. For the anchoring of MoS₂ nanostructures,
∼140 mg of rGO nanosheets was dispersed in 35 mL of deionized
water through ultrasonication for 1 h. Subsequently, 540 mg of ammonium
molybdate tetrahydrate ((NH₄)₆Mo₇O₂₄·4H₄O, 99.99% Sigma) and 1.14 g of
thiourea (CH₄N₂S, 99.8%, Sigma), as molybdenum
(Mo) and sulfur (S) precursors,^{29 (link)} were
stirred into the rGO dispersion for 45 min, following which the dispersion
was transferred to a 100 mL Teflon-lined autoclave and then heated
at 220 °C for 24 h (Figure S1). Likewise,
the free-standing MoS₂ nanostructures were synthesized
by using the same hydrothermal procedure. After cooling to room temperature,
the black precipitate was thoroughly washed with ethanol and distilled
water via centrifugation and then dried overnight at 70 °C.

Iron chloride hexahydrate (1.35 g, FeCl₃⋅6 H₂O, Alfa Aesar, 99 %), polyacrylamide (0.2 g, (C₃H₅NO)_n, Sigma–Aldrich), and thiourea (0.9 g, CH₄N₂S, Sigma–Aldrich, 99 %) were dissolved in deionized (DI) water (80 mL). The mixture was kept under continuous stirring for 60 min at room temperature. Then, the solution was transferred into a 100 mL Teflon‐lined autoclave and heated at 180 °C for 12 h. After washing with DI water several times, the collected black power was finally annealed in Ar/H₂ (Ar/H₂=95:5) at 600 °C for 5 h with a heating rate of 10 °C min⁻¹.