Microkinetic model for WGS over ionic platinum substituted ceria under r-WGS conditions

Mandapaka, Ravikiran; Natarajan, Pradeep; Madras, Giridhar

doi:10.1016/j.ijhydene.2017.03.065

Cited by 3 publications

(2 citation statements)

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“…With the usage of reducible oxides, the interplay of lattice oxygen vacancies and active metal sites in the reaction mechanism is significant. Oxygen vacancies play a crucial role in the adsorption of water and/or CO molecule, active metal sites can enhance the activation of the molecules leading to the formation of intermediates such as carboxyl and formates [10]. CeO 2 is one of such metal oxides that can function as oxygen buffer under exhaust conditions by releasing/acquiring oxygen through redox processes involving the Ce 4+ /Ce 3+ couple [11].…”

Section: Introductionmentioning

confidence: 99%

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Feed Effects on Water–Gas Shift Activity of M/Co3O4-ZrO2 (M = Pt, Pd, and Ru) and Potassium Role in Methane Suppression

et al. 2023

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Water–gas shift (WGS) is an industrial process to tackle CO abatement and H2 upgradation. The syngas (CO and H2 mixture) obtained from steam or dry reformers often has unreacted (from dry reforming) or undesired (from steam reforming) CO2, which is subsequently sent to downstream WGS reactor for H2 upgradation. Thus, industrial processes must deal with CO2 and H2 in the reformate feed. Achieving high CO2 or H2 selectivities become challenging due to possible CO and CO2 methanation reactions, which further increases the separation costs to produce pure H2. In this study, M/Co3O4-ZrO2 (M = Ru, Pd and Pt) catalysts were prepared using sonochemical synthesis. The synthesized catalysts were tested for WGS activity under three feed conditions, namely, Feed A (CO and steam), Feed B (CO, H2 and steam) and Feed C (CO, H2, CO2 and steam). All the catalysts gave zero methane selectivity under Feed A conditions, whereas the methane selectivity was significant under Feed B and C conditions. Among all catalysts, PtCZ was found to be the best performing catalyst in terms of CO conversion and CO2 selectivity. However, it still suffered with low but significant methane selectivity. This best performing catalyst was further modified with an alkali component, potassium to suppress undesirable methane selectivity. All the catalysts were well characterized with BET, SEM, TEM to confirm the structural properties and effective doping of the noble metals. Additionally, the apparent activation energies were obtained to showcase the best catalyst.

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Section: Introductionmentioning

confidence: 99%

“…In this study, Pt facilitated partial reduction in ceria and promoted formate decomposition through enhanced C-H bond rupture rate, and ceria helped bridging the OH groups such that formates could be formed upon CO adsorption. Mandapaka et al [10] studied the WGS over Pt supported on ceria. An associative carboxyl mechanism was proposed.…”

Section: Introductionmentioning

confidence: 99%