Chapter 5
The Reactivity with Hydrogen
and Nitrogen
In this chapter,
1 we present the reactivity of metal clusters with hydrogen and nitrogen
[1–14]. Hydrogen is known as a highly combustible diatomic gas, and the lightest
element on the periodic table. Hydrogen readily forms covalent compounds with
many non-metallic elements and it is an important reducing agent of metallic ores.
The H 2 chemisorption and hydrogen evolution reactions upon metal clusters have
been extensively studied in the past decades in view of the broad interest of hydrogen
storage and green energy sources [15–35].
Nitrogen is the lightest pnictogen and it is the most abundant uncombined element
having an electronegativity of 3.04. An N atom consists of five electrons in its outer
shell allowing a triple bond in molecular nitrogen (N 2 ). The strong N ≡ N triple bond
results in difficulty of converting N 2 into other compounds. Nitrogen is usually unreactive at standard temperature and pressure; however, metal lithium (or magnesium)
does burn in an N 2 atmosphere, giving rise to lithium nitride (or magnesium nitride).
5.1 The Reactivity with Hydrogen
Metal-hydrogen cluster reactivity has been extensively studied with a focus on iron
[19, 36], cobalt [15, 37–43], vanadium and niobium [44–48]. A typical example in
Fig. 5.1 illustrates the reactivity of cationic Fe n
+ and V n
+ clusters with hydrogen (D 2
was used in order to avoid mass degeneracy) [47, 48]. It was found that the presence
of positive charge had a substantial influence on the reaction rate for the majority
of iron and vanadium clusters [19, 49, 50], and the kinetics of D 2 chemisorption on
Fe n
+ /V n
+ clusters exhibited a non-monotonic dependence on n. It is interesting to
mention that, studies of hydrogen chemisorption onto cationic Fe n
+ (n = 4–22) found
a generally enhanced (although size-selective) reactivity compared to that for neutral
1 This chapter is reproduced from Chem. Rev. 2016.
© The Editor(s) (if applicable) and The Author(s), under exclusive license
to Springer Nature Singapore Pte Ltd. 2020
Z. Luo and S. N. Khanna, Metal Clusters and Their Reactivity,
https://doi.org/10.1007/978-981-15-9704-6_5
71
The Reactivity with Hydrogen
and Nitrogen
In this chapter,
1 we present the reactivity of metal clusters with hydrogen and nitrogen
[1–14]. Hydrogen is known as a highly combustible diatomic gas, and the lightest
element on the periodic table. Hydrogen readily forms covalent compounds with
many non-metallic elements and it is an important reducing agent of metallic ores.
The H 2 chemisorption and hydrogen evolution reactions upon metal clusters have
been extensively studied in the past decades in view of the broad interest of hydrogen
storage and green energy sources [15–35].
Nitrogen is the lightest pnictogen and it is the most abundant uncombined element
having an electronegativity of 3.04. An N atom consists of five electrons in its outer
shell allowing a triple bond in molecular nitrogen (N 2 ). The strong N ≡ N triple bond
results in difficulty of converting N 2 into other compounds. Nitrogen is usually unreactive at standard temperature and pressure; however, metal lithium (or magnesium)
does burn in an N 2 atmosphere, giving rise to lithium nitride (or magnesium nitride).
5.1 The Reactivity with Hydrogen
Metal-hydrogen cluster reactivity has been extensively studied with a focus on iron
[19, 36], cobalt [15, 37–43], vanadium and niobium [44–48]. A typical example in
Fig. 5.1 illustrates the reactivity of cationic Fe n
+ and V n
+ clusters with hydrogen (D 2
was used in order to avoid mass degeneracy) [47, 48]. It was found that the presence
of positive charge had a substantial influence on the reaction rate for the majority
of iron and vanadium clusters [19, 49, 50], and the kinetics of D 2 chemisorption on
Fe n
+ /V n
+ clusters exhibited a non-monotonic dependence on n. It is interesting to
mention that, studies of hydrogen chemisorption onto cationic Fe n
+ (n = 4–22) found
a generally enhanced (although size-selective) reactivity compared to that for neutral
1 This chapter is reproduced from Chem. Rev. 2016.
© The Editor(s) (if applicable) and The Author(s), under exclusive license
to Springer Nature Singapore Pte Ltd. 2020
Z. Luo and S. N. Khanna, Metal Clusters and Their Reactivity,
https://doi.org/10.1007/978-981-15-9704-6_5
71