Tuning the metal-support interaction of methane tri-reforming catalysts for industrial flue gas utilization

Review on the catalytic tri-reforming of methane - Part I: Impact of operating conditions, catalyst deactivation and regeneration

“…The higher degree of catalyst deactivation (64.9 %) for Ni/γ-Al 2 O 3 was reported through 80 h-on-stream of reaction, accredited to the phase transformation of alumina making the catalyst inactive at high temperature. A similar observation was described by Pant and the co-workers in their evaluation of Ni-based catalysts prepared at various supports and calcination temperatures for TRM but the discussion was controversial with the former reports [51,70]. For the Al 2 O 3 support, they observed that an increase in calcination temperature led to a higher extent of NiAl 2 O 4 crystallinity, which was responsible for a greater TRM activity due to the reduction of NiAl 2 O 4 produced monodispersed Ni atoms that highly related to Al 2 O 3 phase, which subsequently activated reaction intermediate species enhancing the rate of reforming reaction.…”

“…The degree of graphitization is highly relating to the location between carbon atom and metal nanoparticles. The carbon atoms located in close vicinity of metal nanoparticles have higher tendency to undergo graphitization forming graphitic carbon, which is difficult to be removed in comparison with carbolic and amorphous carbons [51]. In fact, graphitic carbon (γ-C) can exist in various forms such as coating carbon, carbon nanofiber and carbon nanotube.…”

“…However, it also tends to induce re-oxidation of hosting metallic phase on catalyst resulting in a reduction in catalytic performance. In the investigation of metal-support interaction of Ni-based catalysts for TRM (reaction conditions: tubular reactor, at 800 • C, 1 bar, GHSV = 17,220 mL h − 1 g − 1 , molar ratio of CH 4 :CO 2 :H 2 O:O 2 : N 2 = 1:0.23:0.46:0.07:0.28, TOS = 10 h), Kumar et al [51,52] reported that the Ni/SBA-15 possessed excellent resistance towards carbon deposition and great confinement governing the TRM performance with time-on-stream but re-oxidation of partial metallic Ni to NiO was unavoidable, as evidenced by XRD analyses. Such observation is in accordance with the findings of Kim et al in their study of TRM over NiCe@SiO 2 catalysts [77].…”

“…To restrain the mobility of small metal particles at elevated temperature, support with high surface area and great anchor effect towards loaded metal particles has been developed such as SBA-15. In the investigation of metal-support interaction among Ni-based catalysts for TRM in respect of catalytic activity and stability, Kumar et al [51] described that the micropore channels of SBA-15 not only created stronger interaction with NiO species benefiting catalytic activity but also resulted in a great Ni confinement from preventing sintering. In their evaluation of 10 h experimental TRM reaction runs over various Ni-loaded catalysts (Reaction conditions: 800 • C, GHSV = 17,220 mL h − 1 g -1 , molar ratio of CH 4 :CO 2 :H 2 O:O 2 :N 2 = 1:0.23:0.46:0.07:0.28), Ni/SBA-15 exhibited an excellent catalytic stability with insignificant reduction in conversion rates.…”

On the effect of yttrium promotion on Ni-layered double hydroxides-derived catalysts for hydrogenation of CO2 to methane

“…Besides, the TPR results show that MO-0.4Y has the highest intensity of metal-support interaction compared to that of other samples [78]. In conclude, the decreased nickel particle size, increased share of medium-strength basic sites and stronger metal-support interactions found for MO-0.4Y catalyst greatly contributed to the enhanced catalytic activity in CO 2 methanation.…”