Exploring Interface Confined Water Flow and Evaporation Enables Solar-Thermal-Electro Integration Towards Clean Water and Electricity Harvest via Asymmetric Functionalization Strategy

Peng Xiao1,2, Jiang He1,2, Feng Ni1,2, Chang Zhang1, Yun Liang1,2, Wei Zhou1,2, Jincui Gu1 , Junyuan Xia1, Shiao-Wei Kuo3 and Tao Chen1,2*

1 Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Zhongguan West Road 1219, 315201, Ningbo, China. E-mail: (tao.chen@nimte.ac.cn)

2 School of Chemical Sciences, University of Chinese Academy of Science, Beijing 100049, China.

3 Department of Material and Optoelectronic Science, Center of Crystal Research, National Sun Yat-Sen University, 804, Kaohsiung, Taiwan.

Fig. S1 Schematic of the edge of CPPH that was tightly and fully encapsulated by hydrophobic PDMS for a self-floating behavior.

Fig. S2 Schematic of light path of CNTs/paper and CNTs/paper/PDMS hybrid.

Fig. S3 Sketch of formation of close-packed CNTs film at air/water interface through Maragoni effect spread and capillary force driven compression strategy. a-b) Spray-coating for homogenous preassembled CNTs layers. c) A sponge was employed to drive the controllable compression. d) A close-packed CNTs film achieved at air/water interface.

Fig. S4 a) Photo of large-scale CNTs film formed at air/water interface. b-c) SEM images of the assembled CNTs film. d) Cross-sectional SEM image of the CNTs film.

Fig. S5 Schematic of the capillarity driven transfer process, in which the air side of self-assembled CNTs film at air/water interface was further transferred onto the cellulose paper surface in a non-destructive way.

Fig. S6 Photo of cellulose paper that transferred onto the CNTs film surface at air/water interface. b) The transferred CNTs/paper was further washed with water, demonstrating favorable stability. c) The achieved CNTs/paper with uniform CNTs coating.

Fig. S7 Amplified SEM images of the CNTs/paper with 3, 4 and 5 layers, demonstrating a gradual decrease of pores among the CNTs films.

Fig. S8 Light absorption and evaporation rate versus CNTs layers curves, demonstrating a negative correlation between light absorption and evaporation rate.

Fig. S9 a) Sketch of the designed distilled water collection apparatus. b) Photo of the apparatus with large-scale CNTs/paper film. c) Photographs of Water distillation experiment under 10 mins solar irradiation. d) Optical concentration versus time curves of different days at certain temperature and humidity. e) Average evaporation rates of the two days. Inset: the acquired distilled water.

Fig. S10 a) Water flow-induced voltage by partially inserting the carbon nanomaterial films/glass into water with extremely low evaporation area, resulting in low evaporation rate. b) Water flow and evaporation induced evaporation and power generation via a well-designed in-plane structure for an efficient clean water and electricity harvest.

Fig. S11 The schematic illustration of experimental physical map. a) Paper with fibrous structure. b) CNTs film with appropriate layers was alternatively transferred onto one side of the paper surface. c) Hydrophobic PDMS coating was partially applied on the paper side. d) The CNTs film was treated with oxygen plasma to realize good hydrophility. e) Electrode was applied on the CNTs film and further packaged using PDMS, which was located at the opposite PDMS-coated paper. f) A conductive and corrosion-resistant carbon fiber was partially inserted into water to form a circuit to achieve electricity generation. G-h) The electricity generator worked with and without sunlight irradiation. i) The sketch of water-flow-induced ions migration through the porous CNTs network.

Fig. S12 Current versus time curves of single electrode system under different NaCl concentrations.

Fig. S13 PDMS weight content in the PDMS/paper system.

Fig. S14 a) Sketch of the area ratios of PDMS on paper surface ranging from 0.25 to 0.75. b) Generated voltage versus time curves of samples with a series of PDMS area ratios.

Fig. S15 The output voltage a) and current b) versus time curves of single and double electrodes system.

Fig. S16 Induced saturated voltage versus evaporation rate of different multifunctional systems of clean water and electricity harvest.