Carbon dioxide reforming of methane over Ni–In/SiO2 catalyst without coke formation

Abstract

Keywords dry reforming of methane, silica supported nickel catalyst, nickel-indium bimetallic catalyst, coke formation, biogas conversion Highlights· Ni-In/SiO 2 catalysts were prepared by deposition-precipitation with urea. · Both metals were in metallic state after reduction at 700 °C. · Interaction of the two metals was evidenced by TPR, XPS. · The presence of indium in the close vicinity of nickel prevents coke formation. Graphical abstract AbstractThe development of a carbon tolerant nickel catalyst for carbon dioxide reforming of methane (dry reforming of methane, DRM) has been in the focus of catalysis research for several years.In the present study, 3wt%Ni/SiO 2 and bimetallic 3wt%Ni-2wt%In/SiO 2 catalysts (corresponding to 3:1 Ni:In ratio) were prepared by deposition precipitation with urea. Our intention was to modify the nickel surface with a second metal which is known from its ability to reduce surface coke formation. A methane rich reaction mixture (CH 4 :CO 2 :Ar = 2 69:30:1) was used for the catalytic tests at 600 °C and 675 °C. TPO measurements after the catalytic tests showed that there was no surface carbon formation on the indium containing catalyst.Temperature-programmed reduction measurements of the catalysts showed that both nickel and indium was completely reduced after one hour reduction at 700 °C suggesting interaction of the two metals. CO pulse chemisorption experiments revealed that the particle size was similar on the monometallic and bimetallic catalyst, and CO-TPD measurements showed completely different desorption behavior of CO, suggesting the presence of different active sites on the two catalysts. XPS experiments gave similar results, furthermore it was found that after reduction, the Ni/In ratio on the surface was 2.2 compared to the initial value (~3), which refers to the surface enrichment of indium in the bimetallic particles.The lack of coke formation on the indium containing catalyst might be explained by the interplay between a geometric and a chemical effect, that is, indium atoms are most likely situated on the edge and step sites of a nickel particle, influencing reactant adsorption and hindering the growth of carbon nanostructures and/or providing an oxygen rich indium suboxide surface through the reaction with CO 2 in the close vicinity of catalytically active nickel sites, which also inhibits the accumulation of carbon deposits during DRM.

Hindered methane decomposition on a coke-resistant Ni-In/SiO2 dry reforming catalyst

“…3wt%Ni/SiO 2 and 3wt%Ni-2wt%In/SiO 2 catalysts were prepared by deposition-precipitation with urea. The detailed description of the catalyst preparation and the results of their characterization can be found elsewhere [13].…”

“…Therefore, one of the strategies against coking is the modification of the active metal surface with other elements [8][9][10][11][12] to inhibit the formation of multiple bonded carbon species. Following this approach, we have recently shown that on a nickel-indium bimetallic catalyst carbon formation is inhibited during DRM [13].…”

“…The goal of the present study is to provide a deeper insight into the surface processes during methane chemisorption at working temperature (600°C) of the silica supported monometallic Ni and bimetallic Ni-In dry reforming catalysts used in our previous study [13]. Five methane pulses (0.16 μmol each) were added to the freshly reduced catalysts, and to catalysts after 1 min and after 1 h continuous flow of methane (1%CH 4 -He) (partially and extensively carburized samples, respectively).…”

Development of Highly Stable Low Ni Content Catalyst for Dry Reforming of CH4‐Rich Feedstocks

“…In terms of active metal price and loading, productivity and stability against coking, La.Ni(CA)/Mg 1.3 AlO x .1000 is one of the most promising candidates for DRM under CH 4 -rich conditions (Table S. 3). [47,[49][50][51] We conclude that catalysts supported on Mg 1.3 AlO x .1000 possess improved coking resistance without losing the DRM activity and are therefore suitable for the reaction with CH 4 -rich feed. Citric acid induces a high dispersion already during the catalyst preparation.…”

“…These factors are crucial for both carbon removal by CO 2 and stably high DRM performance with high H 2 yield of La.Ni(CA)/Mg 1.3 AlO x .1000. In terms of active metal price and loading, productivity and stability against coking, La.Ni(CA)/Mg 1.3 AlO x .1000 is one of the most promising candidates for DRM under CH 4 ‐rich conditions (Table S. 3) …”