Surfactant-mediated prepared VO2 (M) nanoparticles for efficient solar steam generation

Abstract

Herein, for the first time, we demonstrated the potential practicability of VO2 (M) as a low cost and stable photoabsorber coated on a piece of poplar wood (W/S8-M) in solar steam generation of Caspian Sea water. The evaporation rate of 3.63 kg m−2 h−1 and the solar steam generation efficiency of 75.60% for W/S8-M were obtained under 3 sun (3 kW m−2) irradiation within 40 min. The concentration of sodium ions in the seawater decreased from 3138.19 to 6.61 mg L−1 for W/S8-M which is far below the drinking water standards. The pH and electrical conductivity of seawater was decreased after desalination by W/S8-M to a large extent. A surfactant-mediated method using different amounts of cetyltrimethylammonium bromide (CTAB) was used to prepare VO2 (M). It was revealed that the sample prepared by addition of 0.08 g CTAB using hydrothermal method has the smallest particle size of 230 nm, the largest specific surface area of 14.542 m2 g-1, the greatest mean pore size of 43.53 nm, narrow thermal hysteresis width of 4.12 °C, and the lowest semiconductor–metal phase transition temperature of 65.23 °C. For the first time, the ATR-FTIR spectroscopy was used to monitor the SMT of VO2 (M) at different temperatures. We found that the samples have the same unique ATR-FTIR spectra below Tc with the characteristic band at 835 and a shoulder at 1020 cm−1 while at T > Tc, the fairly linear curves without any meaningful band are appeared.