Wood-polypyrrole composite as photothermal conversion device for solar evaporation enhancement
Wood is gaining more and more concerns for the applications in solar steam generation due to its porous structure with microchannels, low heat conduction property, high hydrophilic property and renewability. The wood surface modification is required for improving the steam generation performance due to its low optical absorptivity. Unfortunately, the high energy consumption fabrication process and high cost of current photothermal conversion coatings on wood impede its large-scale application. Herein, a facile pyrrole polymerization method is developed to acquire polypyrrole decorated wood (PPy-wood) for solar evaporation enhancement. The decoration of black PPy makes the wood light absorption be greatly improved, which leads to a high absorbance (>90%) of PPy-wood within a broad wavelength range from ultraviolet region to near infrared region (300-2500nm). The combination of advantages involving wood (microchanneled porous structure, high hydrophilicity and thermal insulation) and PPy (broadband and high solar absorption capacity) for easy-to-fast steam generation makes the PPy-wood be an ideal solar steam generator, which achieves rapid evaporation ability (1.025 kg m-2 h-1) and high evaporation efficiency (73.2%) under simulated one sun irradiation. Moreover, the obtained clean water using PPy-wood as steam generator shows low ion concentrations and high transmittance, which demonstrates that the PPy-wood possesses excellent ability in seawater desalination and sewage treatment. This kind of PPy-wood is a potential candidate for water desalination and purification to address the water scarcity issue through the effective utilization of clean energy.