Novel Cu and Leaf Nanostructure‐Based Photothermal Biomaterial for Efficient Solar Steam Generation

Abstract

Solar steam generation (SSG) is promising for clean water production owing to low cost, simple operation, and green technology. This work investigates the fabrication of bioinspired photothermal (BIPT) material by sputtering a copper layer on Phanera purpurea (PP) leaf for application in SSG systems. It is observed that the light absorbance of the BIPT material exceeds 92% in the wavelength region of 300–2500 nm. This is due to the light trapping effect caused by multi‐internal reflection inside the Cu‐coated leaf nanostructure. The BIPT material exhibits a low thermal conductivity and easy cleaning properties as a result of PP leaf surface features. A novel strategy in this work is the design of the BIPT material‐based SSG system to recycle the radiative heat loss for evaporation. The developed SSG system results in a solar steam efficiency of 83.7% and a water evaporation rate of 1.45 kg m−2 h−1 under 1 sun. It is also applied in seawater desalination and the produced water satisfies the WHO standards for ion concentrations in clean water. Because of the simple procedure and low cost, the sputtering Cu on the PP leaf can be potentially used in the mass production of BIPT material for seawater desalination.

Recent Advances and Challenges of Metal‐Based Materials for Solar Steam Generation

“…For instance, Chen et al [58] demonstrated a Cu-based photothermal material by a simple chemical oxidation treatment on Cu foam, which showed superior ability on SSG as well as salt-resistance. Tien Thanh Pham et al [59] fabricated bioinspired photothermal material by sputtering a Cu layer on the leaf for the SSG system and it exhibited a high light absorbance of over 92%, resulting in a high solar steam efficiency and water evaporation rate.…”

Solar-driven interfacial evaporation for water treatment: advanced research progress and challenges

“…The evaporation test was carried out using seawater from Bohai Sea in China, and the content of Cl − and Br − measured after evaporation met the standard of seawater desalination. Pham et al 149 fabricated a bioinspired PM by sputtering copper layers on plant leaves, finding that its EE was 83.7% and ER was 1.45 kg m −2 h −1 . Then, desalination experiments were carried out on seawater from the Vietnam Sea, and it was determined that the concentration of anions (Cl − , SO 4 2− , and NO 3− ) was reduced by more than 99.99% after purification.…”

Engineering Materials to Enhance Light-to-Heat Conversion for Efficient Solar Water Purification

“…Several strategies have been proposed to improve the efficiency of SSG by engineering photothermal materials to have strong light absorption over a wide-frequency band (0.2–3 μm) and high photothermal conversion efficiency, as well as designing a substrate to have good thermal insulation to avoid excessive heat loss and capability to supply water to hot regions. They include chemical regulation ,,− and structural engineering ,− of the photothermal materials as well as solar evaporator design. ,− Chemical regulation of photothermal materials is carried out by introducing different elements or functional groups into the primary photothermal material or compositing two or more photothermal materials. Structural engineering includes assembling photothermal materials to specific architecture for the efficient use of the materials in the solar steam generation system.…”