多层级纳米通道实现高效离子选择性输运及盐差能发电

Multilevel nanochannels for high-efficient ion selectivity and salinity gradient power generation

盐差能广泛存在于江河入海口处,蕴藏量巨大.通过反向电渗析法可将盐差能直接转化为电能,因其利用过程简单无污染,近年来受到广泛关注.二维材料的出现为盐差能发电带来新的契机,规则的纳米孔道与丰富的官能团使得其对外输出功率超过了可商业化功率5 W m^(-2);但目前大多研究中盐差能性能测试膜面积仅为3×10^(4)μm^(2),且当测试面积增加时,功率会大幅下降.本文通过简单的真空抽滤法构筑氧化石墨烯与二硫化钼(GOMoS_(2))的2D-2D多层级结构,该结构使得离子选择性膜在较大的面积下仍能保持有序的层状结构,实现高通量高选择性的离子输运,最终输出较高的发电功率.同时,2D-2D结构有效地控制了二维材料膜入水溶胀的问题,提供丰富的表面孔洞与多级层间距,有利于离子的快速选择性运输.大面积膜(面积为3.14 mm^(2),为传统研究的100倍)渗透能测试结果表明,GO-MoS_(2)复合膜的渗透电压与渗透电流都表现优异,在100倍浓度梯度下可获得0.57 W m^(-2)的功率,相较于纯GO薄膜提高了92.7%.2D-2D多层级结构为构筑大面积且制备简单的高效离子选择性薄膜提供了新思路,可为二维材料在盐差能发电乃至海水淡化、气体分离、生物医学等领域的工业化应用提供参考.

Salinity gradient energy is widely present in river estuaries and has a huge reserve.Salinity gradient energy can be directly transformed into electrical energy via reverse electrodialysis,which has recently garnered widespread attention due to its simple and pollution-free utilization process.The emergence of two-dimensional(2D)materials has brought new opportunities because regular nanochannels and abundant functional groups enable their output power density to exceed the commercial standard of 5 W m^(-2).However,the membrane testing area for salinity gradient power generation is generally 3×10^(4)μm^(2),and the power decreases considerably with increasing testing area.In this paper,a 2D-2D multilevel layered structure of graphene oxide and molybdenum disulfide(GO-MoS_(2))is prepared using a simple vacuum filtration method.This structure enables the ion-selective membrane to maintain an ordered structure even over a large area,achieving high ion selectivity and transport and eventually reaching high output power density.Meanwhile,the prepared 2D-2D structure effectively controls swelling in 2D material membranes and offers abundant surface holes and multilevel interlayer spacing,thereby realizing fast ion-selective transport.The osmotic power generation test results over a large area(3.14 mm^(2),100 times larger than those of other studies)showed that the osmotic voltage and current of the GO-MoS_(2) membranes perform satisfactorily,with a power density of 0.57 W m^(-2) at a 100-fold gradient,which is 92.7%higher than those of the original GO membranes.The 2D-2D multilevel layered structure provides a new perspective for fabricating large-area and simple-to-prepare high-performance ion-selective membranes and guidance for the industrial application of 2D materials in the fields of salinity gradient power generation,seawater desalination,gas separation,biomedicine,and so on.