PEDOT:PSS-modified NiFe layered double hydroxide enables efficient and durable seawater electrolysis at high current density

Abstract

Direct seawater electrolysis represents a compelling strategy for green hydrogen production by leveraging Earth’s most abundant water source, yet its practical implementation is critically constrained by the persistent challenge of chloride-induced corrosion. Herein, we report a NiFe layered double hydroxide electrocatalyst modified with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS; denoted as PP), uniformly integrated onto Ni foam (NiFe LDH@PP/NF), for robust alkaline seawater oxidation. Such catalyst needs only 390 mV to achieve 1000 mA cm−2, outperforming NiFe LDH/NF (421 mV). In addition, NiFe LDH@PP/NF can operate continuously for 800 h and 300 h at current densities of 1000 and 2000 mA cm−2, respectively, with negligible performance degradation and minimal active chlorine production. In situ Raman spectroscopy results demonstrate that PP modification promotes catalyst surface reconstruction, thereby enhancing oxygen evolution reaction activity. Importantly, the sulfonate groups (-SO3−) of the PSS component in PP establish an electrostatic repulsion layer during the alkaline seawater oxidation process, effectively mitigating chloride intrusion and thereby enabling stable and efficient catalytic performance. This work delivers a robust and efficient electrocatalyst that addresses the intrinsic challenges of seawater oxidation, marking a significant step toward practical seawater electrolysis.