Performance Study of Methane Dry Reforming on Ni/ZrO2 Catalyst

Abstract

Dry reforming of methane (DRM) has important and positive environmental and industrial impacts, as it consumes two of the top greenhouse gases in order to produce syngas (H2 and CO) and thus hydrogen (H2). The performance of DRM of conversions of CH4 and CO2 was investigated over Ni/ZrO2 catalysts. The catalytic performance of all prepared catalysts for DRM was assessed in a micro-tubular fixed bed reactor under similar reaction conditions (i.e., activation and reaction temperatures at 700 °C, a feed flow rate of 70 mL/min, reaction temperature, and a 440 min reaction time). Various characterization techniques, such as BET, CO2-TPD, TGA, XRD, EDX, and TEM, were employed. The zirconia support was modified with MgO or Y2O3. The yttria-stabilized zirconia catalyst (5Ni15YZr) provided the optimum activity performance of CH4 and CO2 conversions of 56.1 and 64.3%, respectively, at 700 °C and a 70 mL/min flow rate; this catalyst also had the highest basicity. The Ni-based catalyst was promoted with Cs, Ga, and Sr. The Sr-promoted catalyst produced the highest enhancement of activity. The influence of the reaction temperature and the feed flow rate on 5Ni15YZr and 5NiSr15YZr indicated that the activity increased with the increase in the reaction temperature and lower feed flow rate. For 5Ni3Sr15YZr, at a reaction temperature of 800 °C, the CH4 and CO2 conversions were 76.3 and 79.9%, respectively, whereas at 700 °C, the conversions of CH4 and CO2 were 66.6 and 79.6% respectively.

Strontium‐promoted Ni/ZrO2–Al2O3 catalysts for dry reforming of methane

“…The presence of very strong basic sites for 3 and 4 wt% Sr samples suggests that these two samples may not be the most optimized catalysts as excessive basicity of the catalyst is detrimental to catalytic activity since it promotes more CO 2 dissociation (CO 2 → C + O 2 ), triggering deactivation of the catalyst. Indeed, this unfavorable effect intensifies accordingly with the initiation of the Boudouard reaction (2CO → C + CO 2 ) at high temperatures, resulting in a greater amount of coke deposition on the catalyst's surface 34 . The performance of the work is compared with the literature (previously reported findings), as shown in Table of the support information.…”

“…Interestingly, such bands disappear for the highest loading at 4 wt%. It was possible that the addition of Sr at 2 and 3 wt% modified the structure of the basic catalyst (5Ni/10Zr + Al), which could result in the establishment of stable ZrO 2 phases and other mixed phases of zirconium promoter oxide 34 …”

“…33 There is a marked absence of peaks at temperatures lower than 400°C, implying the lack of free NiO. 34 The inverted peaks at around 200°C imply the occurrence of intensely interacting metal-support species-the interaction between the metal species and the support material could potentially lead to a more complex reduction behavior, resulting in the observed inverted peaks. All the catalysts exhibit distinct bimodal profiles, though such profiles are evident at temperatures higher than 500°C with reduction peaks clearly observable at around 550°C and 850°C for catalysts with infused Sr.…”

“…Indeed, this unfavorable effect intensifies accordingly with the initiation of the Boudouard reaction (2CO → C + CO 2 ) at high temperatures, resulting in a greater amount of coke deposition on the catalyst's surface. 34 The performance of the work is compared with the literature (previously reported findings), as shown in Table S1 of the support information. The result confirms the suitability of the present work.…”

Role of promoters over yttria‐zirconia supported Ni catalyst for dry reforming of methane

“…The catalytic activity results with detailed reaction conditions are also mentioned in Supporting Information: Table S2. Metal-promoted "yttria-zirconia supported Ni" is found superior to metal-promoted "tungsten-zirconia supported Ni" catalyst system and quite competitive to metal-promoted "lanthana-zirconia supported Ni" catalyst system 25,26,28,46,51,52 (Figure 9). The promotional effect over 5Ni/YZr catalyst was studied extensively studied where Hopromoted catalyst were found be the best whereas in rest case (5Ni/LaZr, 5Ni/WZr) ceria promoted catalyst showed excellency.…”