Chemical CO2 recycling via dry and bi reforming of methane using Ni-Sn/Al2O3 and Ni-Sn/CeO2-Al2O3 catalysts

Abstract

Carbon formation and sintering remain the main culprits regarding catalyst deactivation in the dry and bi-reforming of methane reactions (DRM and BRM, respectively). Nickel based catalysts (10 wt.%) supported on alumina (Al2O3) have shown no exception in this study, but can be improved by the addition of tin and ceria. The effect of two different Sn loadings on this base have been examined for the DRM reaction over 20 h, before selecting the most appropriate Sn/Ni ratio and promoting the alumina base with 20 wt.% of CeO2. This catalyst then underwent activity measurements over a range of temperatures and space velocities, before undergoing experimentation in BRM. It not only showed good levels of conversions for DRM, but exhibited stable conversions towards BRM, reaching an equilibrium H2/CO product ratio in the process. In fact, this work reveals how multicomponent Ni catalysts can be effectively utilised to produce flexible syngas streams from CO2/CH4 mixtures as an efficient route for CO2 utilisation

Highly efficient Ni/CeO2-Al2O3 catalysts for CO2 upgrading via reverse water-gas shift: Effect of selected transition metal promoters

“…For the Ce-containing catalyst, the addition of CeO 2 gives a broad reduction peak around 250°C due to the Ni-Ce interaction. As previously reported elsewhere, the presence of ceria improves Ni reducibility at lower temperatures and the overall redox properties of all the studied catalysts due to its excellent oxygen mobility [34]. Furthermore, a distinctive peak at a higher temperature (875°C) can be observed on the profiles of Ni/CeAl, NiCr/CeAl and NiFe/CeAl, which is associated to the reduction of bulk ceria [34].…”

Advances in catalytic conversion of methane and carbon dioxide to highly valuable products

“…The surface of nickel catalyst incorporating basic metal oxide is favored by CO 2 adsorption, leading to the increase in CO 2 adsorption that can enhance its reaction with carbon and thus inhibits carbon deposition. The addition of a second metal, such as Co, Cu, and Sn, can form less C‐sensitive alloys . Choi et al.…”

“…demonstrated that a partial coverage of the nickel surface of Ni/Al 2 O 3 by MnO X promoted the adsorption of CO 2 , leading to the decrease in the carbon deposition . Ni/Al 2 O 3 catalyst can also be improved by tin and ceria, leading to enhanced conversion and stability . Noble metals (such as Pt, Ru, and Pd) can remarkably enhance both activity and stability due to their excellent ability to maintain Ni reduced .…”

“…The addition of a second metal, such as Co, Cu, and Sn, can form less C-sensitive alloys. 133,[135][136][137][138][139][140][141] Choi et al examined the effect of Co, Cu, Zr, and Mn as promoters for the Ni/Al 2 O 3 catalyst. 135 They found that, in comparison with unmodified Ni/Al 2 O 3 catalyst, those modified with Co, Cu, and Zr exhibited slightly improved activities, whereas the Mn-promoted catalyst provided a remarkable reduction in coke deposition with only a small decrease in catalytic activity.…”

Controlling the Reduction Extent for Metal Catalysts

“…These processes are usually conducted by exposing the catalysts to certain atmosphere for some time at some prescribed temperatures. Ni catalysts are probably among the most commonly used due to their effectiveness and low costs, they are versatile and have been used in numerous reactions . One of the reactions is dry reforming of methane (DRM), in which two greenhouse gases (CH 4 and CO 2 ) are converted to valuable syngas (H 2 and CO) .…”