Effect of SiO₂ on the CO Selective Methanation over SiO₂/Ni‐ZrO₂ Catalysts

Abstract

CO selective methanation is a reliable and efficient method for deep CO removal from H 2 -rich reformate gases in proton exchange membrane fuel cell (PEMFC). In this study, a series of SiO 2 /Ni-ZrO 2 catalysts with different mass fractions of SiO 2 was prepared for CO selective methanation, and the structures and surface chemical properties of Ni-ZrO 2 could be controlled by SiO 2 . It was found that SiO 2 greatly increased the specific surface areas of the catalyst and the dispersion of supported metallic Ni, which endowed the catalyst with higher active Ni surface area and then increased the adsorption quantity of CO, which improved the conversion of CO at low temperature. More importantly, the SiO 2 weakened the surface basicity over the Ni-ZrO 2 catalyst, and thus decreased the strength and quantity of CO 2 adsorption, which greatly inhibited the methanation of CO 2 , leading to the higher selectivity for CO methanation. However, the strength of CO adsorption was found to be more related to the methanation of CO, which would be weakened by SiO 2 in the catalysts. Meanwhile, the SiO 2 increased the strength of H 2 adsorption over Ni surface. Therefore, excess SiO 2 added into Ni-ZrO 2 enhanced the competitive adsorption between CO and H 2 molecules over Ni surface, which weakened CO adsorption, resulting in the increase of CO outlet concentration.

RuNi/MMO Catalysts Derived from a NiAl-NO3-LDH Precursor for CO Selective Methanation in H2-Rich Gases

“…The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/catal13091245/s1. Table S1: Structural characteristics of the prepared LDHs; Table S2: C and N chemical compositions of LDHs; Table S3: The physicochemical properties of the RuNi/MMO-C and RuNi/MMO-N catalysts; Table S4: The peak areas of CO 2 -TPD for the RuNi/MMO-C and RuNi/MMO-N catalysts; Table S5 [15,20,57,[60][61][62][63][64][65][66][67] are cited in the Supplementary Materials.…”