Tunable Interlayer‐Spacing Graphene Oxide Membrane: Efficient Osmotic Energy Conversion Toward Metal Recovery

under a 500-fold NaCl gradient. Besides, PDA@GO membranes show excellent anti-swelling stability in aqueous solution up to 60 days. Furthermore, integrating green chemistry principles, PDA@GO enables dual energy-resource utilization, successfully recovering copper ions from wastewater via OE. This work highlights the potential of 2D membrane systems in high-efficiency energy conversion and sustainable wastewater treatment.