Structurally Ordered AgNPs@C3N4/GO Membranes toward Solar-Driven Freshwater Generation

Currently, the development of membranes with efficient absorption of solar light has enabled the evaporation and purification of water using solar energy. However, the resolution of the dilemma between the water evaporation rate and the ultradeep removal of contaminants remains a challenge. Here, we report a structurally ordered AgNPs@C3N4/GO (SCG) membrane with both vertical channels and layer nanostructures, which enhance the water evaporation rate and facilitate the removal efficiency of contaminants simultaneously. The water evaporation rate increases by ∼3.5 times in the presence of the SCG membrane, leading to an optothermal conversion efficiency of 77% under a low solar intensity (1 sun) and high humidity (∼65%). More importantly, the as-prepared SCG membrane is capable of clearing diverse contaminants and salts, including dyes, pathogens (e.g., bacteria, viruses, parasites), and metal ions (e.g., Cd2+, Pb2+, Cr2+, Na+, K+, Mg2+, Ca2+), with an extremely high removing efficiency. We envisage that the ordered structure in both vertical and horizontal directions can achieve a large mass flux and highly efficient decontamination. Therefore, it can be expected that the scale-up fabrication of solar absorbers with tailorable nanostructures for thorough wastewater purification and seawater desalination can help people who live in regions with a scarcity of clean water.