# Effect of Pressure-Assisted Heat Treatment on the Crystalline Phase of Titanium Dioxide, Niobium Pentoxide, and Ruthenium-Modified Oxides

## TL;DR

This study shows how pressure-assisted heat treatment changes the structure and properties of titanium dioxide, niobium pentoxide, and ruthenium-modified oxides, making them better for solar-driven reactions.

## Contribution

The study demonstrates that PAHT stabilizes crystalline phases at lower temperatures and enhances solar absorption in modified oxides.

## Key findings

- PAHT significantly reduces the band gap and increases visible light absorption in 100Ti:1Ru oxide.
- Crystalline phases of titanium dioxide and niobium pentoxide are stabilized at lower temperatures with PAHT.
- Sol–gel-derived oxides show improved structural and optical properties after PAHT treatment.

## Abstract

Titanium dioxide,
niobium pentoxide, and ruthenium-modified
tungsten
were synthesized using sol–gel methodology. The effect of pressure-assisted
heat treatment (PAHT) on their structural, morphological, and optical
properties was investigated. The X-ray diffraction, scanning electron
microscopy, energy-dispersive X-ray, UV–vis diffuse reflectance
spectroscopy, and Raman spectroscopy analyses highlighted significant
changes in structural, morphological, and optical properties, especially
in the phase, band gap energy, and visible light absorption after
PAHT. The results indicated that the 100Ti:1Ru oxide, obtained by
the sol–gel method, calcined at 800 °C, and subjected
to PAHT, presented promising characteristics for chemical reactions
activated by solar radiation, with a notable reduction in band gap
and visible absorption. Furthermore, PAHT promoted more stable crystalline
phases at temperatures much lower than those indicated in the literature
related to synthesizing titanium dioxide and niobium pentoxide. These
discoveries contribute significantly to the advancement of knowledge,
providing valuable guidance for developing and optimizing materials
with specific properties for technological applications.