Effect of Neodymium on the Physico‐chemical Properties and N₂O Decomposition Activity of Co(Cu)−Al Mixed Oxides

Abstract

Cu−Al and Co−Al (M/Al=0.8/0.2, molar ratio; M=Cu or Co) mixed metal oxides showed a moderate activity in N2O decomposition (deN2O) with full conversion at about 500–550 °C. Addition of Nd modified the physico‐chemical and catalytic properties of both Cu−Al and Co−Al materials, though an optimal Nd loading was required. The addition of Nd in Cu0.8Al0.2 and Co0.8Al0.2 with Nd/Co(Cu)/Al = 0.5/0.8/0.2 molar ratio, improved significantly their catalytic activity. In particular, the temperatures needed for full N2O conversion were 100 °C lower than those of the bare materials. Furthermore, the most active Nd0.5Co0.8Al0.2 catalyst exhibited a stable 60 % N2O conversion at 450 °C for 50 h in presence of NO (200 ppm), O2 (20,000 ppm) and H2O (2500 ppm). The enhancement in the activity of both Cu‐ and Co‐containing materials was related to the formation of CuNd2O4 for Nd0.5Cu0.8Al0.2 and NdCoO3 for Nd0.5Co0.8Al0.2. The presence of CuNd2O4 or NdCoO3 accounted for changes in redox properties, e. g., easier reduction or faster release of oxygen, and in turn an increased catalyst activity in deN2O. The investigation of rare earth‐based catalysts for deN2O is limited in the scientific literature, while a comprehensive understanding of the involved active species may facilitate a knowledge‐based catalyst optimization.

Strong Electronic Orbit Coupling between Cobalt and Single-Atom Praseodymium for Boosted Nitrous Oxide Decomposition on Co3O4 Catalyst

“…You et al attributed the excellent N 2 O decomposition performance of Ce–Co binary metal mixed oxide to the existence of Ce dopant, which alters the electron transfer pathway of Co 3 O 4 during the N 2 O decomposition and accelerates the O 2 desorption. What needs to be emphasized is that, large radius heteroatoms, such as the light-rare-earth elements Y, Pr, Nd, Sm, etc., can significantly improve the N 2 O catalytic decomposition activity by modifying on the structure and surface properties of the Co 3 O 4 catalyst. ,, However, it is difficult to effectively control its entry into the Co 3 O 4 lattice due to its larger atomic radius than Co. Especially when the catalyst is synthesized by the coprecipitation method, rare earth additives can only be dispersed on the catalyst surface in the form of oxides.…”

Nd6Ir2O13 as an Efficient Electrocatalyst Boosts the Oxygen Evolution Reaction in Acidic Media

“…The highresolution XPS spectra of Nd 3d are displayed in Figure 2a and show a characteristic of Nd multiplet with low binding energy satellites due to the 3d−4f coupling and screening effects. 36,37 Apparently, the Nd 3d spectra of samples before and after OER testing afford a similar spectra shape and can be fitted into two doublets, where the cyan-marked doublet that is located at lower binding energy is ascribed to the satellites. 38 For the second doublet (marked in origin), the Nd 3d 5/2 peak is located at 982.8 eV, indicating that the Nd element is present in the trivalent state, which is assigned to the lattice Nd in Nd 6 Ir 2 O 13 .…”

“…The XPS survey (Figure S4) indicates the presence of Nd, Ir, and O elements in the catalyst. The high-resolution XPS spectra of Nd 3d are displayed in Figure a and show a characteristic of Nd multiplet with low binding energy satellites due to the 3d–4f coupling and screening effects. , Apparently, the Nd 3d spectra of samples before and after OER testing afford a similar spectra shape and can be fitted into two doublets, where the cyan-marked doublet that is located at lower binding energy is ascribed to the satellites . For the second doublet (marked in origin), the Nd 3d 5/2 peak is located at 982.8 eV, indicating that the Nd element is present in the trivalent state, which is assigned to the lattice Nd in Nd 6 Ir 2 O 13 . , In addition, compared with that of the initial sample, the Nd 3d peak intensities of the catalyst after the OER test are dramatically reduced after the OER test, and the Nd signal is decreased to about 23% of its original value.…”

Hydrothermal microwave‐assisted synthesis of LaFeO3 catalyst for N2O decomposition

“…[42][43][44] Various chemical elements can be used as promoting agents. As a rule, in case of spinel-type oxides, alkali, transition metals, and lanthanides are used as promoters, [45][46][47][48][49][50][51][52][53][54][55][56][57][58] while for perovskite-like oxides and hexaaluminates, Ba, Sr, Bi, Sn are often suggested. [36][37][38][59][60][61] Also, in order to decrease the process temperature, the additional reducing agents in a gas mixture can be used, for example, carbon dioxide, methane, and ammonia.…”