Effect of Gd Promoter on the Structure and Catalytic Performance of Mesoporous Ni/Al2O3–CeO2 in Dry Reforming of Methane

UV- and visible-light photocatalysis using Ni-Co bimetallic and monometallic hydrotalcite-like materials for enhanced CO2 methanation in sabatier reaction

The CO2 catalytic reduction activities of four different Co-modified Ni-based catalysts derived from hydrotalcite-like materials (HTCs) prepared by co-precipitation method were investigated under thermal and photocatalytic conditions. All catalysts were tested from 473 to 723 K at 10 bar (abs). The light intensity for photocatalytic reactions was 2.4 W cm-2. The samples were characterized to determine the effect of morphological and physicochemical properties of mono-bimetallic active phases on their methanation activity. The activity toward CO2 methanation followed the next order: Ni > Co-Ni > Co. For the monometallic Ni catalyst an increase of a 72% was achieved in the photo-catalytic activity under UV and vis light irradiation at temperatures lower by > 100 K than those in a conventional reaction. Co-modified Ni based hydrotalcite catalysts performed with stability and no deactivation for the 16 h studied under visible light for methanation at 523 K due to the presence of basic sites.

Hydrogen Production from Gadolinium-Promoted Yttrium-Zirconium-Supported Ni Catalysts through Dry Methane Reforming

Hydrogen production from dry reforming of methane (DRM) not only concerns with green energy but also involves the consumption of two greenhouse gases CH₄ and CO₂. The lattice oxygen endowing capacity, thermostability, and efficient anchoring of Ni has brought the attention of the DRM community over the yttria-zirconia-supported Ni system (Ni/Y + Zr). Herein, Gd-promoted Ni/Y + Zr is characterized and investigated for hydrogen production through DRM. The H₂-TPR → CO₂-TPD → H₂-TPR cyclic experiment indicates that most of the catalytic active site (Ni) remains present during the DRM reaction over all catalyst systems. Upon Y addition, the tetragonal zirconia-yttrium oxide phase stabilizes the support. Gadolinium promotional addition up to 4 wt % modifies the surface by formation of the cubic zirconium gadolinium oxide phase, limits the size of NiO, and makes reducible NiO moderately interacted species available over the catalyst surface and resists coke deposition. The 5Ni4Gd/Y + Zr catalyst shows about ∼80% yield of hydrogen constantly up to 24 h at 800 °C.