Ultrafast synthesis of surface defect-modified Bi/BiOCl nanosheets via the deflagration of NaN3 for solar water evaporation

BiOCl nanosheets modified with Bi nanoparticles and surface oxygen vacancies (BVB) were synthesized in one step within milliseconds via a NaN3 deflagration treatment, in which Na clusters generated from NaN3 deflagration were utilized to capture partial oxygen from BiOCl to generate oxygen vacancies and profuse Bi nanoparticles. Additionally, the concentration of the surface defects and Bi nanoparticles could be tuned by controlling the NaN3 addition. Due to the surface defect and Bi nanoparticle modification, the BVB samples showed enhanced light absorption ability over the whole solar spectrum and improved water evaporation efficiency by 73.9%. Moreover, the deflagration method can also be readily utilized for the preparation of other photothermal materials, providing new insights into the future design of materials.