Dry Reforming of Methane O[sub.x] Catalysts: Tailoring Ga Content for Improved Stability

• Published in: Catalysts 2024-10, Vol.14 (10)
• Main Authors: Elnour, Ahmed Y, Abasaeed, Ahmed E, Fakeeha, Anis H, Ibrahim, Ahmed A, Alreshaidan, Salwa B, Al-Fatesh, Ahmed S
• Format: Article
• Language: English
• Subjects: Adsorption; Air pollution; Analysis; Carbon dioxide; Catalysts; Digital rights (Intellectual property); Greenhouse gases; Methane
• ISSN: 2073-4344; 2073-4344
• DOI: 10.3390/catal14100721

Dry reforming of methane (DRM) is a promising way to convert methane and carbon dioxide into syngas, which can be further utilized to synthesize value-added chemicals. One of the main challenges for the DRM process is finding catalysts that are highly active and stable. This study explores the potential use of Ni-based catalysts modified by Ga. Different Ni-Ga/(Mg, Al)O[sub.x] catalysts, with various Ga/Ni molar ratios (0, 0.1, 0.3, 0.5, and 1), were synthesized by the co-precipitation method. The catalysts were tested for the DRM reaction to evaluate their activity and stability. The Ni/(Mg, Al)O[sub.x] and its Ga-modified Ni-Ga/(Mg, Al)O[sub.x] were characterized by N[sub.2] adsorption–desorption, Fourier Transform Infrared Spectroscopy (FTIR), H[sub.2]-temperature-programmed reduction (TPR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Raman techniques. The test of catalytic activity, at 700 °C, 1 atm, GHSV of 42,000 mL/h/g, and a CH[sub.4]: CO[sub.2] ratio of 1, revealed that Ga incorporation effectively enhanced the catalyst stability. Particularly, the Ni-Ga/(Mg, Al)O[sub.x] catalyst with Ga/Ni ratio of 0.3 exhibited the best catalytic performance, with CH[sub.4] and CO[sub.2] conversions of 66% and 74%, respectively, and an H[sub.2]/CO ratio of 0.92. Furthermore, the CH[sub.4] and CO[sub.2] conversions increased from 34% and 46%, respectively, when testing at 600 °C, to 94% and 96% when the catalytic activity was operated at 850 °C. The best catalyst’s 20 h stream performance demonstrated its great stability. DFT analysis revealed an alteration in the electronic properties of nickel upon Ga incorporation, the d-band center of the Ga modified catalyst (Ga/Ni ratio of 0.3) shifted closer to the Fermi level, and a charge transfer from Ga to Ni atoms was observed. This research provides valuable insights into the development of Ga-modified catalysts and emphasizes their potential for efficient conversion of greenhouse gases into syngas.