# Highly Efficient Solar Steam Generation by W18O49@PVA Gels

## TL;DR

This paper introduces a new material for solar steam generation using oxygen-deficient tungsten oxide in a PVA gel, achieving high efficiency.

## Contribution

The novel use of W18O49 in a PVA gel for enhanced solar steam generation is presented.

## Key findings

- W18O49 was synthesized under high temperature and N2 atmosphere with lattice oxygen escaping.
- The W18O49-PVA gel achieved a steam generation rate of 2.65 kg m−2 h−1, outperforming pure PVA gel.

## Abstract

Oxygen-deficient tungsten oxide W18O49 was synthesized through lattice oxygen escaping at high temperature in N2 atmosphere. The temperature and inert atmosphere were critical conditions to initiate the lattice oxygen escaping to obtain W18O49. The large amount of oxygen vacancies supports its performance in photothermal conversion. The synthesized tungsten oxides were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible absorption spectroscopy (UV-Vis). The composite gel was fabricated by the insertion of oxygen-deficient tungsten oxide into PVA-based gel, which was cross-linked by glutaraldehyde. The PVA-based gel ensures a matched water supply speed with that of the evaporation rate due to its hydrophilic nature. The result of the solar steam generation shows that the W18O49-PVA gel (steam generation rate 2.65 kg m−2 h−1) was faster than that of the pure PVA gel.