In:
Green Chemistry, Royal Society of Chemistry (RSC), Vol. 25, No. 19 ( 2023), p. 7582-7597
Abstract:
Investigation of catalytic hydrogenation of CO 2 to CO via the reverse water–gas shift (RWGS) was undertaken using Ni/SiO 2 -based catalysts. Among the array of catalysts tested, the Ni/SiO 2 catalyst derived from the reduction of silicalite-1-encapsulated, ligand-protected Ni 2+ (Ni 0.2 @S-1-red) exhibited promising performance. This catalyst demonstrated a CO 2 conversion rate approaching the equilibrium conversion of RWGS, a selectivity for CO exceeding 99%, and a high space time yield of CO (9.7 mol g Ni −1 h −1 ). The outcomes observed can be attributed to several factors, such as the highly dispersed Ni 0 and Ni δ + species, as well as the presence of bridging oxygen of the Ni–O–Si structure, on which CO 2 can be adsorbed moderately. The moderately bonded CO 2 on Ni 0.2 @S-1-red allows for the efficient desorption of its reduced intermediate, i.e. *CO, resulting in the generation of gaseous CO at a rapid rate, consequently preventing its deep hydrogenation to CH 4 . Complementary Density Functional Theory (DFT) calculations were performed and revealed that CO molecules have poor adsorption and higher adsorption energy on the Ni@S-1 surface compared to the S-1 surface. This supports the rapid desorption of *CO and the observed high selectivity of CO. Moreover, the structure–activity correlation analysis further supports the claim of Ni 0.2 @S-1-red as a promising RWGS catalyst.
Type of Medium:
Online Resource
ISSN:
1463-9262
,
1463-9270
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2023
detail.hit.zdb_id:
1485110-6
detail.hit.zdb_id:
2006274-6
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