Ni/La₂O₃ Catalysts for Dry Reforming of Methane: Insights into the Factors Improving the Catalytic Performance

Abstract

To understand the structure‐reactivity relationship of Ni/La2O3, and eventually get more applicable catalysts for DRM, glycine nitrate combustion (GNC), precipitation (PP) and thermal decomposition (TD) methods have been used to prepare La2O3 supports. Although all the supports possess a hexagonal La2O3 phase, their bulk and surface properties are significantly changed. By using them as supports, the interactions between NiO/Ni and La2O3 are varied, thus achieving Ni/La2O3 catalysts with different activity, stability and anti‐coking ability, which follow the order of 5Ni/La2O3‐GNC>5Ni/La2O3‐PP>5Ni/La2O3‐TD. On La2O3 having a higher surface area, a catalyst with a higher active metallic Ni surface area can be achieved. Therefore, the interfaces between Ni and La2O2CO3 can be enlarged, which effectively facilitates the reaction between carbon deposits and the La2O2CO3 formed during the DRM, thus preventing the accumulation of both and keeping the catalyst surface clean, active and stable. In addition, the amount of surface alkaline and active oxygen sites of the reduced catalysts obey the order of 5Ni/La2O3‐GNC>5Ni/La2O3‐PP>5Ni/La2O3‐TD, which is well consistent with the reaction performance. Therefore, these two factors are also believed to be critical to decide the reaction performance. It is concluded that Ni/La2O3 catalysts with high activity, stability and potent anti‐coking ability for DRM can be achieved by preparing catalysts with high Ni dispersion.

Solution combustion synthesis of Ni/La2O3 for dry reforming of methane: tuning the basicity via alkali and alkaline earth metal oxide promoters

“…The desorption peaks below 400 C can be attributed to weakly basic sites, the peaks 400-600 C are assigned to basic sites of moderate strength, and the at temperatures higher than 600 C corresponds to strong basic sites. 42,43 The total amount of desorbed CO 2 is larger in Mg-Ni-La 2 O 3 compared to other catalysts, especially CO 2 desorbed from strong basic sites. This implies greater amount and enhanced strength of basic sites which can facilitate the adsorption and activation of CO 2 and enhance the DRM activity.…”

Encapsulated Ni@La2O3/SiO2 Catalyst with a One-Pot Method for the Dry Reforming of Methane

“…As La 2 O 3 can promote CO 2 adsorption and activation [33]; Ni/La 2 O 3 [34,35] and La 2 O 3 promoted Ni-based catalysts [36][37][38][39] have shown excellent activity in the DRM reaction. However, due to the low specific surface area of La 2 O 3 , the main problem with Ni/La 2 O 3 catalysts is the poor dispersion of Ni [40,41], leading to carbon deposition on Ni/La 2 O 3 catalysts [40,41]. Li et al [42] reported ordered mesoporous Ni/La 2 O 3 catalysts with large specific surface area for DRM, and the experimental result indicated that the increased interface between Ni and La 2 O 3 is beneficial for suppressing carbon deposition.…”

Effects of Promoters on the Structure, Performance, and Carbon Deposition of Ni-Al2O3 Catalysts for CO2–CH4 Reforming

“…It is speculated that strong acid sites showed strong decomposition effects for C–C, C–H, and C–O. 34 A higher amount of strong acid sites on Ca-Ni-Al 2 O 3 and Co-Ni-Al 2 O 3 may lead to better catalytic performance. Additionally, medium acid sites were present on Ca-Ni-Al 2 O 3 and Co-Ni-Al 2 O 3 in the temperature range of 400–650 °C.…”