Fabrication of novel Pd-WO3-PPD/GO/ACGS electrode for dual-function in high-performance supercapacitors and efficient water splitting

The development of clean and renewable energy sources as well as supercapacitors to replace fossil fuels is an important challenge to deal with environmental problems. In this study, for the first time, simultaneous electrochemical deposition of poly p-Phenylene diamine (PPD) polymer and tungsten metal oxide (WO₃) followed by electrodoping of palladium (Pd) nanoparticles was carried out on graphene oxide sheets formed on anodized commercial graphite sheet (GO/ACGS). The performance of Pd-WO₃-PPD/GO/ACGS photoelectrode for both hydrogen production and energy storage is investigated. Also, the surface morphology and chemical structure of Pd-WO₃-PPD/GO/ACGS photoelectrode are investigated by FE-SEM, EDX-EDX mapping, ATR-IR, Raman, and XRD tests. Electrochemical behavior investigation of the Pd-WO₃-PPD/GO/ACGS electrode showed excellent capacitance of 635.16 mF cm⁻² at 1 mA cm⁻² and a good hydrogen production ability of 31 mmol cm⁻² after 2 h in 1 M H₂SO₄ electrolyte solution. The results of the fabricated solid-state supercapacitor device show that the fabricated device had a good capacitance of 177 mF cm⁻²), maximum power density of 3500 mW cm⁻², an energy density of 25.02 mWh cm⁻² at 0.5 mA cm⁻² and excellent cyclic stability and coulombic efficiency of 91 % and 99.4 % after 7000 GCD cycles, respectively. The results of the dual application of the fabricated electrode for energy production and storage showed that this electrode has good potential for use in both fields.