Effect of Ce Doping of a Co/Al2O3 Catalyst on Hydrogen Production via Propane Steam Reforming

Abstract

We synthesized cerium-doped cobalt-alumina (CoxCey/Al2O3) catalysts for the propane steam reforming (PSR) reaction. Adding cerium introduces oxygen vacancies, and the oxygen transfer capacity of the Ce promoter favors CO to CO2 conversion during PSR, inhibiting coke deposition and promoting hydrogen production. The best PSR activity was achieved at 700 °C using the Co0.85Ce0.15/Al2O3 catalyst, which showed 100% propane (C3H8) conversion and about 75% H2 selectivity, and 6% CO, 5% CO2, and 4% CH4 were obtained. In contrast, the H2 selectivity of the base catalyst, Co/Al2O3, is 64%. The origin of the difference in activity was the lower C3H8 gas desorption temperature of the Co0.85Ce0.15/Al2O3 catalyst compared to that of the Co/Al2O3 catalyst; thus, the PSR occurred at low temperatures. Furthermore, more CO was adsorbed on the Co0.85Ce0.15/Al2O3 catalyst, and subsequently, desorbed as CO2. The activation energy for water desorption from the Co0.85Ce0.15/Al2O3 catalyst was 266.96 kJ/mol, higher than that from Co/Al2O3. Furthermore, the water introduced during the reaction probably reacted with CO on the Co0.85Ce0.15/Al2O3 catalyst, increasing CO2 generation. Finally, we propose a mechanism involving the Co0.85Ce0.15/Al2O3 catalyst, wherein propane is reformed on CoxCey sites, forming H2, and CO, followed by the conversion of CO to CO2 by water on CeO2 sites.

Influence of CeO2 Addition to Ni–Cu/HZSM-5 Catalysts on Hydrodeoxygenation of Bio-Oil

“…The addition of a small amount of rare earth oxides in the catalyst as a promoter has received considerable attention from different researchers [13,14]. CeO 2 , as an effective redoxagent, can convert between Ce 4+ and Ce 3+ to achieve the conversion between oxygen and oxygen vacancies, resulting in a good oxygen storage capacity [15]. Thus, this work explores the effect of dispersion, particle size, and the reduction ability of the active component of Ni with the addition of CeO 2 based on Ni-Cu/HZSM-5 (Ni:Cu = 8:1).…”

Optimizing CO2 methanation: effect of surface basicity and active phase reducibility on Ni-based catalysts

“…The XRD patterns of the Co-containing samples is comparable to those of the Co-free samples (Fig. 3), with an absence of clear peaks characteristic of either Co 3 O 4 or metallic Co. 62 This can be attributed to the low Co-content used in these samples or to a high dispersion of small Co particles that cannot be detected by XRD.…”

“…61 Cerium introduces oxygen vacancies that can lead to higher conversion of CO to CO 2 during propane steam reforming, for example, preventing carbon deposition and resulting in higher hydrogen production. 62 It has been reported that oxygen defects on the surface of the catalyst play an important role in enhancing CO 2 adsorption, activation, and conversion by hydrogenation into methane. 63 Liu et al 64 revealed an improvement in CO 2 conversion from 45 to 71% upon the addition of 2 wt% CeO 2 to Ni/Al 2 O 3 catalyst during CO 2 methanation at 300 °C and 15 000 ml h −1 g −1 .…”

Dynamic Modeling and Control of a Coupled Reforming/Combustor System for the Production of H2 via Hydrocarbon-Based Fuels

“…Nevertheless, the lack of a reliable distribution network and a safety management handling requires H 2 to be produced from suitable feedstock. The latter can comprise either water electrolysis or hydrocarbons steam reforming [8,9].…”

“…Numerous studies exist in literature and each one delves into a specific area of analysis. Experimental studies that deal with C1-C2 [10][11][12], C3-C4 [9,13], and higher hydrocarbons [14][15][16][17] have already postulated that modeling studies are necessary in order to properly comprehend the system dynamics that involve the interaction of several subsystems. As these subsystems operate continuously and sequentially, such modeling studies can serve as the basis for an advanced control and scaled-up design that will ensure an economically feasible H 2 production.…”