| Facing the formidable challenges caused by global water and energy crises to human existence and progress,the quest for viable solutions has become increasingly critical.Interfacial solar evaporation technology,characterized by its eco-friendly,sustainable,accessible,and cost-effective attributes,emerges as a potent strategy for addressing these crises.Recent advances have been achieved through meticulous selection and tuning of photothermal materials coupled with the design of water and thermal management structures,thereby enhancing the performance of interfacial solar evaporation substantially.However,despite these advances,the evaporation rates of interfacial solar evaporators lag behind those of conventional desalination methods.Three-dimensional（3D）solar interface evaporators,noted for their superior evaporation rates,are a pivotal breakthrough in surmounting existing limitations.The progression of this technology is currently burdened by several challenges:（1）The prevalent focus on macroscopic 3D structure neglects the integration of multi-scale 3D structures,thus restraining potential enhancements in performance;（2）3D evaporators encounter logistical obstacles such as voluminous size,intricate assembly,elevated storage/transportation costs and diminished portability,all of which impede their practical application.Appropriate portability solutions should be designed according to the structural characteristics of different 3D evaporators.To address the above challenges,this thesis harnesses the exceptional solar light absorption capabilities of one-dimensional（1D）tubular carbon nanotubes（CNT）and two-dimensional（2D）planar MXene nanomaterials.These materials are incorporated within jagged and cavity structures to enhance solar light absorption.Benefiting from the vertical channel and top-down 1D water transport structures,water and thermal management are optimized.Consequently,we have developed three novel,highly efficient 3D interfacial solar evaporators.Additionally,by integrating compressible and origami-lantern structures,shape-memory and reversible structural transformation capabilities are introduced to the evaporators,significantly minimizing the space required for storage and transportation.This innovation renders portable3D interfacial solar evaporators a promising solution for satisfying acute water demands in scenarios where storage and transportation pose difficulties,such as small maritime vessels,remote water-scarce islands and underdeveloped arid regions.The research herein details the following aspects:（1）To address the challenges of the limited evaporation rates of 2D evaporators and the proliferation of solid waste due to disposable wooden chopsticks,this thesis employs disposable wooden chopsticks as substrate material and CNT as photothermal material to rapidly and cost-effectively fabricate high-performance 3D interfacial solar evaporators.The inherent material defects in disposable wooden chopsticks lead to a 3D jagged fracture surface upon breakage,resulting in an enlarged effective evaporation area that significantly enhances the absorption of solar light through multiple reflections and absorption.Additionally,the internal vertical channel structure of wooden chopsticks facilitates water transport via capillary action while providing insulation effects.Furthermore,the macroscopic 3D assembly of these chopsticks harnesses the evaporative cooling effect to harvest environmental energy during the evaporation process,thereby enhancing energy efficiency and water evaporation performance.Owing to the synergistic effects of jagged surface structure,internal vertical channel structure and macroscopic 3D structure,the CNT-modified disposable wooden chopsticks evaporator achieves an impressive evaporation rate of 3.70 kg m-2 h-1 and an energy efficiency of122.2%under 1 k W m-2（1 sun）irradiation.This study advances a sustainable and innovative approach for fabricating high-performance 3D interfacial solar evaporators utilizing waste disposable wooden chopsticks,showing the potential of repurposing waste materials to mitigate the global water crisis.（2）To address the challenges of the voluminous dimensions,inferior mechanical properties and compromised portability of porous structure 3D interfacial solar evaporators,this thesis introduces a novel dehydration-compression-swelling strategy to realize high-density storage and transportation.The approach entails the sequential spaying of MXene and polyvinyl alcohol onto the surface of a lignocellulosic sponge（designated as PMLS）to obtain a portable 3D interfacial solar evaporator with shape-memory function.The effectiveness of this strategy is validated through experimental investigation.Specifically,in an inactive state,PMLS can be compressed to merely～9%of its original thickness,thereby substantially diminishing the requisites for storage and transportation space with a remarkable space-saving rate of 89.3%.Upon activation,PMLS can swiftly resume its pre-compression dimensions through water absorption and expansion while maintaining the integrity of the photothermal layer and porous structure.Under 1 sun irradiation intensity,PMLS evaporator demonstrates an exceptional evaporation rate of 2.48 kg m-2h-1 and an energy efficiency of 95.5%.Moreover,the performance of PMLS stably endures across long-term continuous evaporation,14 evaporation cycles,8 evaporation cycles without water supply and 8 dehydration-compression-expansion-evaporation cycles.The capabilities of PMLS extend to efficient desalination and the purification of various wastewaters.Remarkably,high-density storage and transportation can be realized through diverse compression techniques.These features demonstrate the stability and applicability of PMLS evaporator across a spectrum of application scenarios.This work advances the portable design of porous structural 3D interfacial solar evaporators,offering novel considerations for simultaneously enhancing performance and portability.（3）To address the challenges of the voluminous footprint,intricate assembly and limited portability of geometrical structure 3D interfacial solar evaporators,this thesis introduces an innovative origami-lantern shaped 3D evaporator（designated as OLCE）endowed with reversible structure transformation function.Leveraging the inherent predictability of origami deformability,OLCE realizes smooth transformations between 2D and 3D structures through the straightforward process of folding and expanding,achieving a remarkable space-saving rate of 92.5%.The design incorporates quadrilateral cavity units that induce a light-trapping effect,thereby enhancing light absorption,and the total spherical shape ensures the capacity to harness sunlight from any direction.Additionally,the incorporation of the top-down water transport structure guarantees continuous water supply,essential for sustained evaporation.Evaporation experiments of OLCE under 1 sun reveal an exceptional evaporation rate of 2.15 kg m-2 h-1 and an energy efficiency of95.7%.Related experiments demonstrate the robust structural integrity and operational stability of OLCE,alongside its effectiveness for seawater desalination and wastewater purification.Furthermore,the incorporation of convective flow into the system substantially enhances the evaporation rate of OLCE,exhibiting a markedly pronounced convective flow-evaporation response compared to 2D evaporators.Notably,under 1 sun and a convective flow intensity of 3 m s-1,OLCE achieves a high evaporation rate of 8.62 kg m-2 h-1.This research delineates a pathway toward designing and realizing geometrical structure 3D interfacial solar evaporators with outstanding evaporation performance and high portability,offering significant implications for future advancements in the field. |
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