Formation and reactivity of nitrides I. Review and introduction

Abstract

Methods of nitride production are summarised and their thermodynamics surveyed. Crystal structures and types of bonding in binary and ternary nitride compounds are classified and discussed. Kinetics of nitride formation are related to structural changes in the materials, which control diffusion of metals and nitrogen and cause nitride scaling. Metal nitridation with ammonia and nitride formation during ammonia synthesis are discussed.Information so far available on the sintering of nitrides and its effect on their chemical reactivity is reviewed. This effect is influenced by additives or impurities such as oxides formed by partial nitride hydrolysis and oxidation. Sintering and hot pressing increase the resistance of nitrides to hydrolysis and oxidation, so that they become more suitable for use as refractories. Often, corrosion resistance of nitride layers on metal surfaces is impaired by poor scaling resistance in air or oxygen at comparatively low temperatures. The kinetics and products of oxidation of nitrides so far studied, notably AIN, TiN and UN, depend mainly on the intrinsic reactivity of the material and the available surface at which oxidation can occur.Subsequent work will be concerned with changes in phase composition, surface area and crystallite and aggregate sizes and their correlation with production, sintering, hydrolysis and oxidation conditions for single and mixed nitrides. Suitable experimental techniques are summarked in this paper.

The Role of Non‐Metallic and Metalloid Elements on the Electrocatalytic Activity of Cobalt and Nickel Catalysts for the Oxygen Evolution Reaction

“…Nitrides of Co and Ni have recently attracted attention as low‐cost electrocatalysts for the OER in alkaline electrolytes . Reports indicate that the Co and Ni nitrides are essentially interstitial compounds in which the N atoms occupy interstitial sites within the lattice of the host metal . Electron transfer is generally from interstitial nitrogen to the metal lattice .…”

Thermodynamics of metal reactants for ammonia synthesis from steam, nitrogen and biomass at atmospheric pressure

“…Nitridation computed at 1,000 K (except Co 3 N at 600 K, Zn 3 N 2 at 700 K, and AlN, Ca 3 N 2 , Cr 2 N, CrN, Mn 4 N, Mn 5 N 2 , and Mo 2 N at 800 K) is represented by a linear fit (dashed line, individual data points omitted for clarity, for details see Additional Supporting Materials online). Increasing the nitridation temperature to a kinetically reasonable value37, 38 positions some elements that are attractive due to their low metal‐oxygen bond energy, at a region with positive Δ nit G , i.e., nitride formation is not favored (Figure 2). Formation of these nitrides requires elevated N 2 pressure and/or nitrogen activation (e.g., plasma dissociation or other activated N sources)39 if the nitride is only stable at low temperatures.…”

“…A correlation similar to that in Figure 4 is observed: Elements forming an undesirably strong bond with oxygen tend to liberate NH 3 on nitride hydrolysis. Increasing the hydrolysis temperature37, 38 decreases the tendency for formation of NH 3 and favors undesirable N 2 formation (computed at 800 K, except Co 3 N at 600 K, and Zn 3 N 2 at 700 K).…”

“…These nitrides are composed mainly of metal cations and N 3− anions 20, 37. Hydrolysis of these materials forms NH 3 readily and rapidly37, 38 (criteria 2), but also highly stable oxides (violating criteria 3 and 6).…”

Freeze-dried precursor-based synthesis of new polymetallic oxynitrides, V1−u−zCruMoz(OxNy),V1−u−zCruWz(OxNy), Cr1−u−zMouWz(OxNy) (u, z=0.2, 0.33, 0.4, 0.6, u+z<1), and VzCrzMozWz(OxNy) (z=0.25)

“…Although monometallic nitrides have been widely investigated since the decade of the fifties of the last century [32], the chemistry of polymetallic nitrides remained for much 0925 time unexplored because of limitations imposed by the available preparative techniques. In practice, it was the application of the novel synthetic chemistry -developed from around the middle of the decade of 1980 (in some way, a legacy of high temperature superconductivity) -which opened new prospects in this seemingly residual area.…”