The effects of stoichiometry on the properties of exsolved <scp>Ni‐Fe</scp> alloy nanoparticles for dry methane reforming
Soham Shah, Samuel Sayono, Jenna Ynzunza, Ryan Pan, Mingjie Xu, Xiaoqing Pan, Kandis Leslie Gilliard‐AbdulAziz
Abstract
Abstract The dry reforming of methane has received notable attention as a chemical process to convert natural gas into value‐added chemicals and fuels. Ni‐based exsolution catalysts using perovskite oxides supports have been used for their attractive sinter‐resistance and coke‐resistance properties. The perovskite oxide in itself has unique defect chemistry that can be used to manipulate and control the properties of the catalyst nanoparticles exsolved on the surface, therefore influencing both the nanoparticle and support characteristics. In this study, the La:Fe ratio of Ni‐doped LaFeO 3 was used to manipulate and control the properties of exsolved Ni‐Fe alloy nanoparticles. The Ni‐Fe nanoparticles consisted of different sizes ranging from 10 to 380 nm. Temperature programmed surface reaction studies along with materials characterization with SEM, STEM‐HAADF, XRD, and BET showed that the Ni‐Fe nanoparticles from different solid precursors have the same active sites for methane activation but differ in performance and stability because of size effects, metal‐support strength, composition and support basicity. A mechanism is proposed to decipher the merits of the Ni‐Fe nanoparticles with the best activity, selectivity, and stability in this study.