Advanced Architectural Amorphous Co@PAT Electrocatalyst: Flexible and Sustainable Tri-functional Water Oxidation and Solar to Hydrogen Conversion for Energy Future

Abstract

Developing efficient transition metal-based electrocatalysts for water oxidation (OER, UOR, and seawater splitting) is important for hydrogen production. Here, we report a solvent-free method to prepare an amorphous cobalt-based catalyst (Co@PAT), enriched with sulfur and nitrogen, using polymerization followed by auto-combustion. On a glassy carbon electrode, the catalyst (4R Co@PAT/GC) shows a low overpotential of 290 mV at 10 mA cm⁻², a small Tafel slope of 96 mV dec⁻¹, and excellent stability for 25 hours with only ~2% potential loss in 1.0 M KOH. When coated on nickel foam (4R Co@PAT/NF), it performs even better, requiring just 250 mV at 10 mA cm⁻², with a Tafel slope of 40 mV dec⁻¹ and ultra-stable operation over 180 hours (~1.4% loss). These results outperform many precious metal catalysts. In a full water-splitting cell, 4R Co@PAT reaches 1.54 V at 10 mA cm⁻² and remains stable for over 240 hours (~2.53% loss). Impressively, 4R Co@PAT/NF also shows high efficiency in urea oxidation (1.40 V; 25h) and seawater splitting (1.54 V; 25h). Under solar radiation, 1.53 V is enough to split water effectively. The amorphous structure and the integration of heteroatoms greatly enhance its performance, offering new insights for designing multifunctional electrocatalysts for hydrogen production