Multi-Metal Phthalocyanine-Based Synergistic Bifunctional Electrocatalysts for Solar-Driven Seawater Splitting

High Resolution Image Download MS PowerPoint Slide Developing efficient electrocatalysts for seawater splitting that operate at high current densities with long-term durability remains a significant challenge for sustainable green hydrogen generation. In this study, we report a simple one-pot hydrothermal synthesis of multi-metal phthalocyanine (Pc) catalysts incorporating Fe, Co, Ni, and Cu (FeCoNiCu-Pc) directly grown on nickel foam, which serves as a bifunctional electrocatalyst for solar-driven seawater splitting. The integration of multiple transition metals within the Pc macrocycle induces synergistic electronic interactions and optimized charge distribution, thereby facilitating enhanced electrocatalytic activity. Among the synthesized catalysts, FeCoNiCu-Pc demonstrates nearly two-fold higher activity for both the oxygen evolution (OER) and hydrogen evolution reactions (HER) compared with the single-metal-Pc counterparts. It requires minimum overpotentials of 315, 322, and 380 mV for the OER and 239, 308, and 318 mV for the HER in alkaline KOH, alkaline simulated seawater, and alkaline real seawater, respectively, at a current density of 100 mA cm −2 . Furthermore, FeCoNiCu-Pc demonstrates remarkable durability, maintaining a maximum of its initial activity over 50 h at a current density of 100 mA cm −2 while maintaining its rod-like morphology. An electrolyzer fabricated using FeCoNiCu-Pc as both the anode and cathode reached 100 mA cm −2 at 1.69 V in alkaline real seawater electrolytes. As a proof of concept, the fabricated cell also exhibits stable performance under solar-driven conditions.