Operando DRIFTS investigation of active intermediates in CO2 methanation over Ni–La/γ-Al2O3 under low H2/CO2 feed ratios

ÖZTEPE C., ORDULU O., Uzun A., EROPAK B. M., SELEN ÇAĞLAYAN B., AKSOYLU A. E.

International Journal of Hydrogen Energy, cilt.218, 2026 (SCI-Expanded, Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 218
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.ijhydene.2026.154023
  • Dergi Adı: International Journal of Hydrogen Energy
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Artic & Antarctic Regions, Chemical Abstracts Core, Chimica, Compendex, Environment Index, INSPEC
  • Anahtar Kelimeler: CO 2 utilization, CO 2 methanation at low H 2 /CO 2 ratio, Operando DRIFTS, Active intermediate, Ni-based catalysts
  • Boğaziçi Üniversitesi Adresli: Evet

Özet

Operando FTIR-DRIFTS-MS was employed to investigate the CO2 methanation mechanism over Ni–La/γ-Al2O3 under conditions representative of methane-to-hydrogen fuel processor systems, particularly at low H2 to CO2 feed ratios of 1 to 1. This study provides mechanistic insight into a largely unexplored operating regime, revealing that CO2 methanation proceeds predominantly via hydrogen-assisted CO2 dissociation. Weakly bridged CO species emerged as the most likely active intermediates associated with methane production. Through a combination of qualitative surface analysis and quantitative correlation between deconvoluted IR peak areas and methane production, a strong relationship was identified between weakly bridged CO and CH4 formation, while formate species exhibited spectator behavior. These findings enhance understanding of the reaction pathway over Ni–La/γ-Al2O3 under non-stoichiometric, low H2/CO2 feed conditions and support the rational design of improved CO2 utilization catalysts for FP-PEMFC systems, contributing to carbon capture and sustainable energy technologies.