Ammonia Reduction-Induced V₂O₃ Nanomaterial for Solar Steam Generation

Vanadium oxides with multiple oxidation states have shown various potential applications in energy conversion and storage due to their unique chemical and electrical properties. However, solar energy harvesting and conversion based on V 2 O 3 (V 3+ ) can rarely be witnessed in the literature. Herein, we demonstrated an effective method to prepare a V 2 O 3 nanomaterial by annealing a V 2 O 5 precursor in an ammonia-rich atmosphere, and the resulting V 2 O 3 nanomaterial showed strong solar energy absorption and photothermal conversion capability. Evaporators of V 2 O 3 /PVA/melamine foam (MF) exhibited high evaporation rates of up to 2.75 kg m –2 h –1 under 1 sun irradiation, which was 2.0 and 1.7 times higher than those of PVA/MF and V 2 O 5 /PVA/MF evaporators, respectively. Moreover, the V 2 O 3 -based evaporator also displayed high desalination capacity in salty water and retained excellent multicycle stability. In addition, it was also worth mentioning that our V 2 O 3 evaporators displayed high evaporation rates over 2.50 kg m –2 h –1 for natural sources of water from local rivers and lakes under 1 sun irradiation, demonstrating promising applications for clean water production. Our work broadens the material family for solar energy harvesting and conversion, offering insights into the design of highly effective evaporators for solar steam generation.