2.2 Solar Vapour Generation under 1 Sun
Ultraviolet-visible near-infrared (UV-Vis-NIR) measurements (Figure 3a) display excellent solar absorption properties of MF@HPB-PPyn-OA. The MF@PPy10-OA has good light absorption in the spectral range of 200-2500 nm because of the PPy coverage on MF. The absorption of MF@HPB-PPy10 is visibly strengthened in the Vis-NIR region when the HPB component with excellent light absorption properties in Vis-NIR is introduced. Based on the advantages of the 3D porous structure of MF@HPB-PPy10-OA and the stability and homogeneity of the HPB-PPy10-OA coating, MF@HPB-PPy10-OA demonstrates nearly
complete light absorption (95.3%, weighted under AM 1.5G), presenting excellent photothermal conversion potential. In Figure 3b, the surface temperature of MF@HPB-PPy10-OA in the dry state rapidly increases to 89.5 oC and remains stable within 3 min under 1 sun. The photothermal conversion capacity of MF@HPB-PPy10-OA is obviously higher than that of MF, MF@PPy10-OA and MF@HPB-PPy10, which is attributed to the superiority of HPB composition (Figure S6) and the unique surface structure. When MF@HPB-PPy10-OA is in the wetted state, the temperature steady-state value of surface is slightly lower than that of MF@PPy10-OA and MF@HPB-PPy10 (Figure 3c). Specifically, the absorbed sunlight is applied to the photothermal water evaporation, thus the lower temperature steady-state value implies stronger evaporation efficiency. The photothermal water evaporation experiments further confirm the above results. Before executing the water evaporation, MF@HPB-PPyn-OA improves the evaporation area and the internal temperature of structure by tailoring the edges into an orthogonal prismatic table structure (Figure S7 and Figure S8c). As displayed in