A multifunctional PANI-wrapped Bi2WO6 2D-nanoplates with in-situ grown BiOCl nanocomposite for electrochemical seawater splitting, supercapacitor, and photocatalytic applications

Hydrogen has the potential to play a critical role in the energy transition by decarbonizing hard-to-electrify areas and facilitating storage. Sea water electrolysis is an approach with the greatest potential for this transition to large-scale green hydrogen production using renewable energy owing to the availability of seawater instead of requiring chemical electrolytes. In this study, a novel nanocomposite comprising Bi₂WO₆, PANI, and in-situ grown BiOCl (BW-BIC-PANI) was synthesized via a hydrothermal route followed by a chemical oxidative polymerization route. The BW-BIC-PANI nanocomposite is intended for multifunctional use as a high-performance electrocatalyst for hydrogen evolution reactions in various electrolyte mediums, supercapacitors, and photocatalysis. The electrocatalytic performance of BW-BIC-PANI₂₀₀ electrode in the HER was accompanied by a high catalytic current density of −101.7, −104.7, and −98.4 mA cm⁻² and also lower Tafel slope values of 58.48, 123, and 188 mV dec^-1 under acidic, alkaline, and seawater mediums, respectively. The seawater water splitting for HER utilizing BW-BIC-PANI₂₀₀ composites electrode, at a current density of 10 and 40 mA cm⁻² at the fixed applied potential, depicted a durability of 12 and 24 h, respectively. The BW-BIC-PANI₂₀₀ composite has a specific GCD capacitance of 156F g⁻¹ at 1 Ag⁻¹. Also, GCD stability was achieved after 4000 cycles with minimal capacitance loss. Furthermore, the BW-BIC-PANI200 composite shows high photocatalytic activity, degrading MO aqueous dye up to 71.75 % after 80 min of illumination. The findings clearly show that the BW-BIC-PANI₂₀₀ nanocomposite might serve as a potential multifunctional electrocatalyst for efficient water electrolysis, supercapacitors, and photocatalysis.