Enhanced CO₂ Methanation Activity of Ni/Anatase Catalyst by Tuning Strong Metal–Support Interactions

Abstract

Strong metal−support interaction (SMSI) has been widely recognized for platinum-group metals on reducible oxide supports. Herein we report that the catalytic activity of Ni catalyst in CO 2 methanation is significantly suppressed over conventional anatase (a-TiO 2 ) support due to the SMSI-induced formation of a titania overlayer around the Ni nanoparticles. Furthermore, CO is the only product . In contrast, the NH 3 -treatment and H 2 -treatment of the a-TiO 2 support enhance remarkably the activity of Ni, i.e., CO 2 conversion increases by 1 order of magnitude and CO 2 is hydrogenated almost exclusively to CH 4 . X-ray photoelectron spectroscopy (XPS), H 2 and CO chemisorption, and low temperature electron paramagnetic resonance (EPR) reveal that the enhanced CO 2 methanation activity may be related with the Ti 3+ species in the bulk that are generated by reduction treatment, which likely have altered the SMSI between Ni and a-TiO 2 support. This simple reduction treatment approach may be applicable to modulate the SMSI of other reducible oxide-supported metal catalysts.

Silica accelerates the selective hydrogenation of CO2 to methanol on cobalt catalysts

“…But cobalt is regarded as inappropriate for the selective methanol formation, because of the its high activity for C-O dissociation 34 , and CO and hydrocarbons usually form rather than methanol 35 . On the other hand, recent efforts on selectivity optimization in CO 2 hydrogenation have focused on engineering metal oxide supports with redox properties and electronic metal-support interactions 1,2,[36][37][38] , but the promotion role of inert supports, such as silica, has been largely overlooked.…”

Enhancing the CO2 methanation activity of Ni/CeO2 via activation treatment-determined metal-support interaction

“…There is evidence in the existing literature showing that appropriate interaction between Ni and TiO 2 can be generated with partial support reduction (Ti 4+ ? Ti 3+ ) and formation of surface oxygen vacancies at the interface region via hightemperature reduction [15]. The enhanced reactivity observed over Ni/TiO 2 can be linked to the activation treatment-determined metal-support interaction.…”

“…The product CH 4 , the primary component of natural gas, can be stored and transported in the existing natural gas network and used as needed [14]. In addition, the CO 2 methanation finds important applications in submarines, space crafts, and space stations as a crucial component of energy and life support system [15]. CO 2 methanation (Sabatier reaction) is an exothermic reaction, which is thermodynamically favored at lower temperatures [14].…”

Catalytic Reduction of CO2 to CO via Reverse Water Gas Shift Reaction: Recent Advances in the Design of Active and Selective Supported Metal Catalysts

“…Depending on metal properties, Pd-and Pt-based catalysts are selective for producing CO, whereas catalysts based on oxophilic metals, such as Ni, Rh, and Ru, are more selective for producing CH 4 [55][56][57][58][59]. CH 4 can be a minor or major product under a RWGS reaction condition in the presence of these catalysts [55][56][57][58][59]. Thus, in addition to improving activities, tuning the selectivity of catalysts toward the RWGS reaction is important.…”

“…Interestingly, the redispersed Ru/CeO 2 catalyst via a mild oxidizing treatment is stable in a RWGS reaction for 12-14 h, and CO selectivity increases further from 90% to 99%. Similarly, the high-temperature (500 °C) reduction of a Ni/TiO 2 catalyst results in a SMSI effect with a decreased activity, but this reaction shifts the selectivity from CH 4 to CO (Table 1) because Ni is covered, and more Ni-TiO 2 interface sites are produced [57]. However, for the supported Ni catalysts prepared from NH 3 or H 2 -pretreated TiO 2 support, reduction at 500 °C only induces a SMSI effect to a limited extent; thus, CH 4 is the dominant product on these catalysts ( Table 1).…”