In recent years, solar-induced interfacial heating of water has proven to be an efficient technique to produce steam while harnessing solar energy. Herein, we report diesel soot coated on cotton as a novel photothermal membrane for highly efficient solar steam generation. A facile fabrication procedure was successfully followed to synthesize the photothermal membrane with hazardous diesel soot particles obtained from vehicular exhaust, and cotton cloth. In this photothermal membrane, the diesel soot particles embedded in the cotton cloth substrate help in the absorption of incident solar illumination, and the excellent hydrophilicity of cotton cloth assists in the rapid supply of water at the air-water interface to produce constant steam. As a result, the evaporation rate of water using the photothermal membrane was 3 times the bare water system with an excellent photothermal efficiency of 91.75% under 1 sun illumination. The photothermal membrane was also successful in water desalination using a simple laboratory setup. The results of this work should motivate further research of diesel soot and other waste products for high efficiency water evaporation and its applications.