Ultrathin CuNi-rGO catalytic nanofiltration membranes via in-situ growth and slow deposition for enhanced catalysis-separation performance

The practical development of catalytic membranes is still hindered by two key challenges: limited catalytic-separation performance arising from insufficient control over active sites and excessively thick active layers, and weak interfacial coupling between catalytic nanoparticles and two-dimensional (2D) nanosheets. To address these issues, we propose an in-situ growth coupled with slow deposition strategy for constructing ultrathin graphene oxide (GO)-based catalytic nanofiltration membranes. This approach enables the formation of an interconnected porous architecture of reduced graphene oxide (rGO) nanosheets decorated with uniformly distributed bimetallic nanocrystals. Electronic interfacial interactions between Ni₂O₃ and Cu₂O nanocrystals promote electron transfer from Ni and Cu toward oxygen, thereby modulating the bonding strength and improving catalytic functionality. Through these synergistic effects, the rGO framework contributes to enhanced catalytic activity and structural stability. The resulting membrane, with a thickness of only 62 nm, delivers a high water permeance of 99.6 L m⁻² h⁻¹ bar⁻¹, while maintaining a rejection rate of 99.1% and achieving over 99% catalytic reduction efficiency for 4-NP. Moreover, Cu and Ni ions cross-link the rGO nanosheets into a robust nanostructure, enabling the CuNi-rGO membrane to sustain both catalytic activity and separation performance for at least 120 h. This mixed-dimensional self-assembly strategy provides a general design framework for constructing high-performance catalytic nanofiltration membranes based on other 2D nanomaterials.