Catalysts Promoted with Niobium Oxide for Air Pollution Abatement

Abstract

Pt-containing catalysts are currently used commercially to catalyze the conversion of carbon monoxide (CO) and hydrocarbon (HC) pollutants from stationary chemical and petroleum plants. It is well known that Pt-containing catalysts are expensive and have limited availability. The goal of this research is to find alternative and less expensive catalysts to replace Pt for these applications. This study found that niobium oxide (Nb 2 O 5 ), as a carrier or support for certain transition metal oxides, promotes oxidation activity while maintaining stability, making them candidates as alternatives to Pt. The present work reports that the orthorhombic structure of niobium oxide (formed at 800 • C in air) promotes Co 3 O 4 toward the oxidation of both CO and propane, which are common pollutants in volatile organic compound (VOC) applications. This was a surprising result since this structure of Nb 2 O 5 has a very low surface area (about 2 m 2 /g) relative to the more traditional Al 2 O 3 support, with a surface area of 150 m 2 /g. The results reported demonstrate that 1% Co 3 O 4 /Nb 2 O 5 has comparable fresh and aged catalytic activity to 1% Pt/γ-Al 2 O 3 and 1% Pt/Nb 2 O 5 . Furthermore, 6% Co 3 O 4 /Nb 2 O 5 outperforms 1% Pt/Al 2 O 3 in both catalytic activity and thermal stability. These results suggest a strong interaction between niobium oxide and the active component-cobalt oxide-likely by inducing an oxygen defect structure with oxygen vacancies leading to enhanced activity toward the oxidation of CO and propane.

Commemorative Issue in Honor of Professor Calvin H. Bartholomew’s 75th Birthday

“…Türks et al's work on CO 2 methanation on nickel catalysts builds on these major themes of Dr. Bartholomew's research [18]. Finally, the contribution by Xiang et al [19], whose corresponding author is Dr. Bartholomew's long-time collaborator, Bob Farrauto [20], echoes some of his earliest work on environmental catalysts. In summary, this special issue covers much of the breadth and points to the depth of Professor Emeritus Calvin H. Bartholomew's illustrious career.…”

Green Magnetic Nanoparticles CoFe2O4@Nb5O2 Applied in Paracetamol Removal

“…Methodi Ordinatio classified 211 articles, and the InOrdinatio value ranged from −12.79 to 579.75, when we used 10, 8, and 8 for ∆, λ, and Ω values, respectively. The main keywords that appear in the articles were: ferrite (97); magnetic (80); cobalt (65); nanoparticle (37); degradation (35); catalyst (30); photocatalysis (28); oxide (27); dye (25); CoFeO (24); heterogeneous (22); and nanocomposites (22) (Figure 1). Another relevant bibliometric analysis is about the years of publication of the more significant InOrdinatio articles, 63% of the publications are concentrated between 2019 and 2023, Figure 2a.…”

“…Niobium pentoxide (Nb 2 O 5 ) and its combinations with other compounds have been studied as photocatalysts. Researchers report the efficiency of the photocatalytic activity of niobium oxide in the degradation of dyes in textile industries [28] and of herbicides such as methylviologen [29], as well as in the reduction of atmospheric pollution [30] and emerging pollutants [31,32].…”

Photocatalytic Activity of Cu2S/WO3 and Cu2S/SnO2 Heterostructures for Indoor Air Treatment

“…The development of urban areas and industrial activities has significantly decreased indoor and outdoor air quality. Volatile organic compounds (VOC) are commonly found in indoor spaces (home or office) and are often related to various illnesses, some of them with carcinogenic potential [1][2][3]. The origins of VOC release in the indoor environment are in office products, building materials, electronics, cleaning products, furniture and maintenance products.…”