This work reports the electrochemical performance of PANI coated RuO ₂ /TiO ₂ (RTO) macroporous structures. The PANI-RTO nanocomposites were binder-free deposited on FTO glass substrates by electrostatic spray deposition (ESD). According to physical characterizations, the content of RTO has a strong influence on the morphology of nanocomposites, and hence, on their specific surface area and hydrophilicity. Electrochemical studies performed in a 0.1 M aqueous solution of H ₂ SO ₄ demonstrate that PANI-10RTO electrode exhibit the best transport properties, with an energy density of 18.1 Wh kg ⁻¹ at a power density 150 W kg ⁻¹ within a potential window of 0‒0.6 V vs Ag/AgCl. Furthermore, it shows a coulombic efficiency of 99.8% and capacitance retention above 81.6% after 10,000 charge/discharge cycles. Based on these results, symmetric supercapacitor devices (SSDs) of PANI-10RTO//PANI-10RTO were assembled. When the SSD was operated in a potential window of 0‒0.6 V, it provides a capacitance of 67.4 F g ⁻¹ at 0.2 A g ⁻¹ alongside a specific energy of 3.37 Wh kg ⁻¹ at 60 W kg ⁻¹ .

Composite materials based on polyaniline and graphite were prepared using in situ polymerization of an aniline monomer without any previous treatment. Three monomer/graphite weight ratios during polymerization were studied, which were 1:1, 1:2, and 1:3. The composite materials showed a nanochain-like structure whose dimensions vary with the graphite content. Materials were deposited over a fluorine-doped tin oxide (FTO) substrate to evaluate its capacitive performance. The electrochemical measurements carried out in a 0.1 M aqueous solution of H₂SO₄ showed that PANI-Gr1 composite electrode exhibits a capacitance of 238 F·g⁻¹ at 0.5 A·g⁻¹ within a potential window of 0–0.6 V vs. Ag/AgCl. At a current density of 4.0 A·g⁻¹, the PANI-Gr1 composite shows an energy density of 3.0 Wh·kg⁻¹ that is 30% higher than pure PANI, results due to an increase in electrical conductivity concomitant with the morphology change and surface area increase. Composite materials showed promising properties as easily processable and scalable electrodes for supercapacitors.

Enhanced Performance of Sn@Pt Core-Shell Nanocatalysts Supported on Two Different Carbon Structures for the Hydrogen Oxidation Reaction in Acid Media: Sn@Pt core-shell nanocatalysts, supported on Vulcan XC-72 and home-developed nitrogen-doped graphene (Sn@Pt/C and Sn@Pt/NG, respectively), were evaluated for the hydrogen oxidation reaction (HOR) in acid electrolyte. The nanocatalysts were synthesized by the bromide anion exchange (BAE) method. TEM characterization confirmed the nanosize nature of Sn@Pt/C and Sn@Pt/NG, with an average particle size of 2.1 and 2.3nm, respectively. Sn@Pt/C delivered a similar mass limiting current density (j_{l, m}) of the HOR compared to Sn@Pt/NG, which was higher than those of Pt/C and Pt/NG (ca. 2 and 2.3-fold increase, respectively). Moreover, the Sn@Pt/C and Sn@Pt/NG core-shell nanocatalysts demonstrated a higher specific activity related to Pt/C and Pt/NG. Mass and specific Tafel slopes further demonstrated the improved catalytic activity of Sn@Pt/C for the HOR, followed by Sn@Pt/NG. The application of the nanocatalysts was proposed for polymer electrolyte membrane fuel cells (PEMFC).