Physicochemical changes caused by the use of pulsed laser activation technique in the metals and alloys of the Ti-V-Nb-Cr system for hydrogen storage

• Grant number: 24/03659-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2024
• End date: February 28, 2026
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Guilherme Zepon
• Grantee: Ana Rodrigues Cameirão
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Hydrogen is a viable alternative to fossil fuels because it is an energy vector of clean and renewable sources. However, its use is still dependent on the development of safe and efficient storage and transportation systems. An efficient way to store H2 is in the solid state through metal hydrides. Multicomponent alloys of the Ti-V-Nb-Cr system, for example, are capable of reversibly reacting with H2 to form hydrides capable of storing about 3 wt.%. of H. However, when these alloys are exposed to air for long periods, it is necessary to perform activation procedures so that the alloy is able to absorb hydrogen. The most widely used activation procedure for multi-component alloys consists of heating the sample at temperatures above 300 ºC under dynamic vacuum for a few hours. In this context, our group was the pioneer in reporting a new method that uses pulsed laser to activate alloys for hydrogen storage, called PLA (Pulsed Laser Activation). However, the mechanisms involved in laser-matter interaction during the PLA method are not completely understood. Thus, this master's project has as its main objective the study of the surface physicochemical alterations arising from the PLA method in samples of the pure elements Ti, V, Nb and Cr and an alloy of this system. The hydrogenation properties of these materials after exposure to air, after thermal activation and after PLA activation will be investigated. The samples under different conditions will be characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy. The structural characterization data will be analyzed and compared with the hydrogenation properties of the materials, in order to understand the mechanisms involved in the PLA process.