Deuteride Materials

Deuterium is the basis of deuterated compounds. The studies on deuterium element (atom) and elemental deuterium have nearly a hundred years of history. In the past studies, deuterium atom has played an important role in the development of quantum mechanics. As an isotope of hydrogen, deuterium exhibits a significant isotope effect without any radioactive characteristic, which has attracted considerable attention in scientific communities with an emphasis on the nuclear applications. Historically, the demand of war promoted and developed nuclear weapons, which in turn promoted the rapid development of deuterium research. Until the 1990s, the global trend of dearmation changed the world’s theme from the Cold War to peace and started the era of peaceful economic development. Under these global circumstances, the applied research of deuterium shifted to a large extent in the fields of engineering and natural sciences such as energy, materials, and medicine, and showed a huge potential application.

Because deuterium is an isotope of hydrogen that has most of the properties of hydrogen, deuterium can react with nearly every element in the periodic table to generate the corresponding deuterium-containing compounds. In nature, there are many forms of deuterium, such as elementary deuterium, organic compounds, polymers, inorganic compounds, metal compounds, coordinative compounds, etc. Elemental deuterium has always been an important area of ​​research. For example, deuterated polymers, inorganic deuterides, metal deuterides and alloy deuterides have been the hot topics studied in military and energy recently. The potential value of deuteride, as a special isotope compound, has not yet been really explored.

Similar to hydrides, deuterides have been involved in a variety of fields. They can be prepared by the preparation methods of hydrides, but with unique characteristics due to the lack of deuterated raw materials. Their preparation methods can be classified into two types, direct synthesis with perdeuterated reactants via the routes to the corresponding hydrides and the deuteration of corresponding hydrides. The former has been well-established and can afford highly pure deuterides, but requires perdeuterated solvents, reagents, catalyst, and atmosphere, which increases the production cost for cluster-type, systematic, and large-scale production of deuterides.

Since structural characterization is an important means to determine the structural properties of materials, it is an important part of the study of deuterides. The structure of deuterides plays a critical role in its properties. From the point of view of the material, it is necessary to be familiar with the structure and properties of deuterides to understand, utilize, and even design the deuterides correctly.

This chapter will focus on the deuterium absorption and desorption characteristics of metal deuterides and alloy deuterides. Among all deuterides, metal deuterides have the most types with the longest and most in-depth study history, and the widest and most mature applications. Because metal deuterides have excellent deuterium adsorption and desorption characteristics, they have many functions, and can be used as deuterium storage carriers, deuterium sources, thermonuclear reaction materials, etc. In order to study and evaluate the deuterium adsorption and desorption of metal deuterides or alloy deuterides, their chemical thermodynamic and kinetic properties, such as the desorption pressure–composition–temperature profile (p-c-T curve), plateau pressure, hysteresis, hydrogen adsorption and desorption amount, reaction heat, activation performance, expansion rate, hydrogenation reaction rate, cycle life, thermal conductivity, alloy toxicity, stability, and many other indicators, must be tested. Meanwhile, deuterium, as an isotope of hydrogen, has completely different thermodynamic and kinetic performance from hydrogen and tritium in the process of hydrogen absorption and desorption. Therefore, the isotope effect of deuterium absorption and desorption will be included in this chapter.

Deuterium compounds were initially used in the military and energy fields, primarily in nuclear weapons, nuclear energy industry, deuterium fluoride-based chemical laser weapons, and so on. Indeed, nuclear fusion research has led to the development of high-power lasers, high-power microwaves, intense beam technology, and cryogenic superconductivity. Later, as a special functional material, deuterated compounds are stable in nature without radioactivity, which play an important role and become more and more widely used in the fields of civil materials, agriculture, fishery, biomedical research, pharmaceutical research, chemical theory research, earth science, analytical testing, new material research and development.