Multicomponent Nacre-Like Heterogeneous Nanochannels with Ion Sieving and Light-Sensitivity Properties for Improved Energy Conversion

Nanochannel membranes are currently being employed for selective ion transport and salinity gradient energy capture. However, the poor functionality of nanochannel membranes and the unfavorable influence of multivalent cations result in low energy conversion efficiency, limiting the energy conversion performance of nanochannel membranes. Herein, multicomponent nacre-like heterogeneous nanochannels composed of carboxymethyl chitosan (CMC)-intercalated composite two-dimensional (2D) GO, C₃N₄ nanosheets, and polyethylene terephthalate (PET) channels are developed using an interfacial assembly strategy. Benefiting from the asymmetric structure, the heterogeneous membrane achieves enhanced ion diffusion and unidirectional ion transport behaviors. Subsequently, a high power density of 8.46 W/m² is achieved in artificial seawater and river water by the heterogeneous membrane. Notably, the introduction of CMC into 2D lamellar channels endows the heterogeneous membrane with outstanding ion sieving performance, thereby mitigating the unfavorable influence of divalent cations on energy conversion, reducing it from 32.08% to 19.85%. Furthermore, the heterogeneous membrane exhibits sensitive and stable light-responsive ion transport behavior, profiting from the light sensitivity of GO and C₃N₄ nanosheets, and an improvement of 11.29% in energy conversion performance can be accomplished with light irradiation. This work proposes an idea to design multifunctional nanochannel membranes to achieve highly efficient salinity gradient energy conversion.