Catalytic Combustion of Toluene over Cobalt Oxides Supported on Graphitic Carbon Nitride (CoOx/g-C₃N₄) Catalyst

Abstract

Graphitic carbon nitride (g-C3N4) supported CoOx catalysts were prepared by the impregnation method and comprehensively characterized by XRD, N2 physisorption, TEM, H2-TPR, and XPS. The catalytic performance tested by catalytic combustion of toluene indicates that 10% CoOx/g-C3N4 catalyst exhibits the highest activity, achieving a toluene conversion of 90% at a temperature of approximately 279 °C, compared with other CoOx catalysts supported on SBA-15, γ-Al2O3 and activated carbon (AC). The specific structure of g-C3N4 made it a N and electron-rich material, which might be the reason for the existence of Co3O4 active phase, high surface Co3+ content and high density of surface oxygen adsorption species, and facile reducibility of Co3+. Moreover, no significant decrease in catalytic efficiency is observed over different temperature stages on the 10% CoOx/g-C3N4 sample, which indicates that the catalyst’s stability is excellent under the conditions required for toluene combustion.

Efficient Aerobic Oxidation of Ethyl Lactate to Ethyl Pyruvate over V2O5/g-C3N4 Catalysts

“…It is worth noting that 13V 2 O 5 /g-C 3 N 4 has the highest surface O ads /O latt ratio among these catalysts. Previous studies have shown that the surface-adsorbed oxygen (O ads ), which is located at surface defects, is easier to reduce. − Other literature has also shown that the surface-adsorbed oxygen is the most active species in aerobic oxidation, which promotes the exchange of gaseous oxygen with the surface-adsorbed ones. − Since a high surface O ads /O lat ratio means the facile activation of oxygen molecules on the catalyst, the above results are quite consistent with the catalytic activities.…”

Catalytic Removal of Toluene from Air Streams by Cobalt Oxide Supported on Sepiolite

“…But further increase in the cobalt loading did not enhance the catalytic efficiency, so that Co15/Sep exhibited similar catalytic activity for toluene degradation with that of Co20/ Sep. This finding is in agreement with Luo et al 40 study which reported that increasing the cobalt loading from 5 to 10% will enhance the catalytic efficiency of the catalyst with no enhancement in higher than 10% cobalt loadings. Table 2 makes a comparison on the catalytic activity of Co20/Sep in T 50 and T 90 with cobalt catalysts on different supports for removal of toluene reported by other researchers.…”

Preparation of mesoporous CexCoO as highly effective catalysts for toluene combustion: The synergetic effects of structural template and Ce doping

“…[53] T A B L E 2 Summary of the reported data of toluene combustion over Co-based catalysts and cobalt oxide catalysts [42] Co/Sr CeO 2 Toluene 1,000 20,000 h −1 . 237 253 Luo et al [43] L-12 Toluene 1,000 10,000 h −1 263 272 Feng et al [44] Co 3 O 4 NC Toluene 1,000 20,000 h −1 264 267 Zhang et al [10] Co 3 O 4 Toluene 1,000 40,000 ml g −1 h −1 262 268 Mo et al [45] Spherical Co 3 O 4 Toluene 1,000 20,000 ml g −1 h −1 249 266 Wang et al [46] Co 1.5 Mn 1.5 O 4 Toluene 1,000 30,000 ml g −1 h −1 263 267 Jiang et al [25] 3D Co 3 O 4 C Toluene 1,000 48,000 ml g −1 h −1 240 248 Ren et al [9] La 0.95 Ag 0.05 CoO 3 Toluene 1,000 30,000 cm 3 g −1 h −1 238 268 Liu et al [47] CuCo 0.5 /C Toluene 1,000 40,000 ml g −1 h −1 237 243 Chen et al [48] Ce…”

“…In the midst of all the catalysts, the Ce 0.07 CoO shows the best catalytic activity when the temperature is lower than 220 C; however, Ce 0.05 CoO exhibits superior catalytic oxidation performance while temperature higher than 220 C and achieves the toluene conversion of 90% at 238 C that is 19 C lower than that of the Co 3 O 4 C. For the past few years, extensive researches have been carried out on the catalytic oxidation of toluene over Co-based catalysts, the catalytic activities (evaluated by T 50% and T 90% ) of some of them are listed in Table 2. A lot of data shows, the Ce 0.05 CoO sample exhibits a better catalytic activity than many of them, such as CoO x /g-C 3 N 4 (T 50% = 268.2 C, T 90% = 279.2 C), [43] Co/Sr CeO 2 (T 50% = 237 C, T 90% = 253 C), [44] L-12 (T 50% = 263 C, T 90% = 272 C), [45] Co 3 O 4 NC (T 50% = 264 C, T 90% = 267 C), [10] Co 3 O 4 (T 50% = 262 C, T 90% = 268 C), [46] spherical Co 3 O 4 (T 50% = 249 C, T 90% = 266 C), [47] Co 1.5 Mn 1.5 O 4 (T 50% = 263 C, T 90% = 267 C), [25] 3D Co 3 O 4 C (T 50% = 240 C, T 90% = 248 C), [9] La 0.95 Ag 0.05 CoO 3 (T 50% = 238 C, T 90% = 268 C), [48] CuCo 0.5 /C (T 50% = 237 C, T 90% = 243 C). [52] Figure 9b discloses the yields of CO 2 over different catalysts.…”