Water pollution caused by domestic and industrial sewage exacerbates the shortage of freshwater, with major negative consequences for society and the environment. Solar-to-steam energy conversion systems, namely the extraction of steam using solar energy, are a promising eco-friendly and cost-effective approach for water purification. However, current technologies still exhibit low efficiency and high energy consumption. Here we report a polymer wastewater collector with a cross-scale hierarchical structure based on Defective polypyrrole-modified activated carbon paper substrate (DPAC), and its use for sporadic wastewater collection and efficient solar-driven sewage purification. Strong absorption of the solar spectrum at an arbitrary incident angle was achieved, which continuously provides heat for evaporation. Water molecules are prone to aggregate around the defective polypyrrole networks, where the generated heat is directly transferred to the water molecules, resulting in a low heat loss and high conversion efficiency for purifying seawater. In addition, DPAC exhibits superior domestic and industrial sewage evaporation rates of 1.37 and 1.28 kg m−2h−1 under one sun irradiation with corresponding solar-to-steam conversion efficiencies of 91.8% and 85.8%, respectively. The principle of this solar steam generator may provide useful insights towards the efficient and energy-saving treatment of domestic and industrial sewage.
