Dimethyl Ether Oxidation over Copper Ferrite Catalysts

Abstract

The depletion of fossil energy sources and the legislation regarding emission control demand the use of alternative fuels and rapid progression of aftertreatment technologies. The study of dimethyl ether (DME) catalytic oxidation is important in this respect, as DME is a promising clean fuel and at the same time a VOC pollutant present in the tail gases of industrial processes. In the present work, copper ferrite catalysts synthesized via the citrate complexation method have been evaluated in DME oxidation. N2-physisorption, XRD, H2-TPR, and XPS were employed for the characterization of the mixed oxide catalysts. The copper ferrite spinel phase was detected in all samples accompanied by a gradual decrease in the bulk CuO phase upon increase in iron content, with the latter never vanishing completely. The Fe0.67Cu0.33 catalyst exhibited the highest catalytic activity in DME oxidation, attaining approximately a 4-fold higher oxidation rate compared to the respective pure copper and iron oxides. The enhanced catalytic performance was attributed to the higher specific surface area of the catalyst and its enhanced redox properties. Highly dispersed copper species were developed owing to the formation of the spinel phase. DME-TPD/TPSR experiments showed that the surface lattice oxygen of the Fe0.67Cu0.33 catalyst can oxidize preadsorbed DME at a lower temperature than all other catalysts which is in agreement with the H2-TPR findings.

Effects of Exchange Correlation Functional (Vwdf3) on the Structural, Elastic, and Electronic Properties of Transition Metal Dichalogenides

“…The calculated real and imaginary parts of frequency-dependent microscopic dielectric function in the energy range of 0 to 21 eV were plotted. The imaginary parts of the dielectric function of MoS 2 (Figure 4), MoSe 2 (Figure 5), and MoTe 2 (Figure 6) were obtained from interband transition for the parallel and perpendicular direction of the electric field as computed from equation (3) [5], however, the real part of the frequency-dependent dielectric function was obtained from Kramers-kroning relation as shown in equation ( 6) [2]:…”

“…Recent studies have revealed that LDA exhibits overestimations of the lattice constants for a and c of 0.4 % and 5.2 %, and GGA underestimates c by 4 % while overestimating a by 0.58 %, respectively. This problem persisted in TMDs, especially in terms of their mechanical, electronic, and optical characteristics [5]. In this research, a full demonstration of the effects of Van der Waals forces on the mechanical, electronic, and optical properties of TMDs was carried out with MoX 2 (X = S, Se, and Te).…”

Copper Ferrite Nanoparticles Synthesized Using Anion Exchange Resin: Influence of Synthesis Parameters on the Cubic Phase Stability

“…In addition, they have various technological applications such as energy storage devices [4], magnetic storage media [5], spintronic and electromagnetic devices [6; 7]. Besides, ferrites were used as catalysts for photocatalytic degradation of organic matter [8,9,10], oxidation of dimethyl ether [11] and mercury [12], and reduction of 4-nitrophenol [13]. The spinel structure of ferrites provides additional sites for the catalytic reaction, which leads to an increase in the efficiency of the photocatalytic decomposition [14,15].…”

Copper Ferrite Nanoparticles Synthesized Using Anion-Exchange Resin: Influence of Synthesis Parameters on the Cubic Phase Stability

“…They also have various technological applications such as energy storage devices [ 4 ], magnetic storage media [ 5 ], and spintronic and electromagnetic devices [ 6 , 7 ]. Furthermore, ferrites have been used as catalysts for the photocatalytic degradation of organic matter [ 8 , 9 , 10 ], oxidation of dimethyl ether [ 11 ] and mercury [ 12 ], and reduction of 4-nitrophenol [ 13 ]. The spinel structure of ferrites provides additional sites for the catalytic reaction, leading to an increase in the efficiency of photocatalytic decomposition [ 14 , 15 ].…”