Integrated synthesis and comprehensive characterization of TiO2/AgBi2S3 ternary thin films via SILAR method.

AgBi2S3, a copious and innocuous ternary metal chalcogenide affiliated with the I-V-IV group of semiconductors, was synthesized. With an energy gap of 1.2eV, it closely matches the optimal 1.39eV for solar cell absorbers. Importantly, this chalcogenide exhibits a high absorption coefficient of 105 cm-1 at 600 nm. Using the successive ionic layer adsorption and reaction (SILAR) method; we deposited an AgBi2S3 thin film onto a titanium dioxide (TiO2) thin film. Characterization techniques encompassed XRD, SEM, EDXS, UV-Vis, EIS, and PEC performance analyses. The resulting TiO2/AgBi2S3 composite film ranged in thickness from 8 µm to 13 µm, with particle sizes spanning 20 nm-265 nm. Notably, the deposition of AgBi2S3 onto the TiO2 film caused depreciation in the TiO2 energy gap from 3.1eV to 1.7eV. Furthermore, it significantly enhanced the TiO2 film's absorbance across the visible and near-infrared regions. Intriguingly, the TiO2/AgBi2S3 composite film also exhibited discernible photoelectrochemical behavior.

One-Pot Synthesis of Ruthenium-Based Nanocatalyst Using Reduced Graphene Oxide as Matrix for Electrochemical Synthesis of Ammonia.

Conventional ammonia production consumes significant energy and causes enormous carbon dioxide (CO2) emissions globally. To lower energy consumption and mitigate CO2 emissions, a facile, environmentally friendly, and cost-effective one-pot method for the synthesis of a ruthenium-based nitrogen reduction nanocatalyst has been developed using reduced graphene oxide (rGO) as a matrix. The nanocatalyst synthesis was based on a single-step simultaneous reduction of RuCl3 into ruthenium-based nanoparticles (Ru-based NPs) and graphene oxide (GO) into rGO using glucose as the reducing agent and stabilizer. The obtained ruthenium-based nanocatalyst with rGO as a matrix (Runano-based/rGO) has shown much higher catalytic activity at lower temperatures and pressures for ammonia synthesis than conventional iron catalysts. The rGO worked as a promising promoter for the electrochemical synthesis of ammonia due to its excellent electrical and thermal conductivity. The developed Runano-based/rGO nanocatalyst was characterized using transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), inductively coupled plasma mass spectrometry (ICP-MS), and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the size of the Ru-based NPs on the surface of rGO was 1.9 ± 0.2 nm and the ruthenium content was 25.03 wt %. Bulk electrolysis measurements were conducted on thin-layer electrodes at various cathodic potentials in a N2-saturated 0.1 M H2SO4 electrolyte at room temperature. From the chronoamperometric measurements, the maximum faradic efficiency (F.E.) of 2.1% for ammonia production on the nanostructured Runano-based/rGO electrocatalyst was achieved at a potential of -0.20 V vs reversible hydrogen electrode (RHE). This electrocatalyst has attained a superior ammonia production rate of 9.14 µg·h-1·mgcat.-1. The results demonstrate the feasibility of reducing N2 into ammonia under ambient conditions and warrant further exploration of the nanostructured Runano-based/rGO for electrochemical ammonia synthesis.