Interrelating platinum single atom-tuned cobalt phosphide-based 2D flake network via multi–layer carbon nanotube bridges for high-efficiency water splitting

Developing efficient and durable electrocatalysts for overall water splitting (OWS) under industrial conditions currently remains a critical challenge. This study introduces a rational method for developing high–performance functional catalysts of two-dimensional transition metal phosphide flake network interrelated by conductive carbon nanotube bridges (CoP/NC–CNT), which is further integrated with a small amount of atomically dispersed Pt (Pt–CoP/NC–CNT), thus resulting in rapid hetero-charge transport and abundantly exposed active sites. Interestingly, the CoP/NC–CNT material could serve as an effective OER catalyst with a low required overpotential (η) of 212 mV while Pt–CoP/NC–CNT delivers an outstanding HER activity exhibiting a remarkable η of 33 mV at 10 mA·cm⁻². Impressively, the fabricated anion exchange membrane water electrolyzer (AEMWE) stack based on Pt–CoP/NC–CNT₍₋₎||CoP/NC–CNT₍₊₎ could deliver a high current density of 500 and 2000 mA·cm⁻² at a stack voltage of only 1.85 and 2.19 V, respectively. In addition, its performance shows a slight decline with a degradation rate of just ∼50 μV·h⁻¹ after over 1000 h. This work demonstrates a scalable and durable approach to designing high-performance and low-cost electrocatalysts for efficient alkaline water electrolysis, offering strong potential for industrial hydrogen production.