Advanced-architecture amorphous Co@PAT electrocatalyst: flexible and sustainable tri-functional water oxidation and solar-to-hydrogen conversion for the energy future†

Developing high-performance electrocatalysts based on transition metals for water oxidation (OER, UOR and seawater splitting) is essential for H₂ production. Herein, we present a solvent-free amorphous cobalt-embedded S,N-enriched carbon (Co@PAT) electrocatalyst prepared by polymerization followed by an auto-combustion method. On an inert surface, the active electrocatalyst 4R Co@PAT/GC presents a low overpotential of 290 mV at 10 mA cm⁻² with small kinetics (96 mV dec⁻¹) and stability over 25 h with minimum loss of potential (∼2%) in 1.0 M KOH. Typically, 4R Co@PAT coated on an active NF surface (4R Co@PAT/NF) exhibits an overpotential of 250 mV at 10 mA cm⁻² with smaller kinetics (40 mV dec⁻¹) and ultra-durability over 180 h with minimum a potential loss of ∼1.4% in 1.0 M KOH. These ideal performances are superior to those of precious-metal catalysts. A full cell with 4R Co@PAT as the anode exhibited 1.54 V at 10 mA cm⁻² and high stability for more than 240 h with a potential loss of ∼2.53%. Surprisingly, the efficiency of 4R Co@PAT/NF is retained in the UOR (1.40 V; 25 h) and seawater (1.54 V; 25 h) splitting. In solar-to-hydrogen production, 1.53 V solar radiation effectively splits water. Overall, the 4R Co@PAT exhibits superior electrocatalytic activity, with the amorphous nature of the catalyst greatly enhancing the flexibility and the integration of heteroatoms significantly boosting the electrocatalytic activity, which affords new prospects for the expansion of the high potential of multi-functional electrocatalysts for H₂ generation.