Classical strong metal-support interaction (SMSI) describes that reducible oxide migrates to the surface metal nanoparticles (NPs) to obtain metal@oxide encapsulation structure during high-temperature H 2 thermal treatment, resulting in high selectivity and stability.
However, the encapsulation structure inhibits the adsorption and dissociation of reactant molecular (e.g., H 2 ) over metal, leading to low activity, especially for the hydrogenation reaction.
Recently, a research group led by Prof. LIU Yuefeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has proposed a new migration strategy, in which the TiO 2 selectively migrates to second oxide support rather than the surface of metal NPs in Ru/(TiO x )MnO catalysts, boosting the CO 2 reduction to CO via reverse water-gas shift reaction.
This study was published in Nature Catalysis on Oct. 9.
The researchers achieved controlled migration by utilizing the strong interaction between TiO 2 and MnO in Ru/(TiO x )MnO catalysts during H 2 thermal treatment, and TiO 2 spontaneously re-dispersed on the MnO surface, avoiding the formation of TiO x shell on Ru NPs for the ternary catalyst (Ru/TiO x /MnO).
Meanwhile, high-density TiO x /MnO interfaces generated during the process, acting as a highly efficient H transportation channel with low barrier, and resulting in enhanced H-spillover for the migration of activated H species from metal Ru to support for consequent reaction.
The Ru/TiO x /MnO catalyst showed 3.3-fold catalytic activity for CO 2 reduction to CO compared with Ru/MnO catalyst. In addition, the Ti/Mn support preparation was not sensitive to the crystalline structure and grain size of TiO 2 NPs. Even the mechanical mixing of Ru/TiO 2 and Ru/MnO x enhanced the activity.
Moreover, they verified that the synergistic effect of TiO 2 and MnO didn't alter the catalytic intrinsic performance, and efficient H transport provided a large number of active sites (hydroxyl groups) for the reaction process.
"Our study provides references for the design of novel selective hydrogenation catalysts via the in-situ creation of oxide-oxide interfaces acting as hydrogen species transport channels," said Prof. LIU.
Nature Catalysis
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Generation of oxide surface patches promoting H-spillover in Ru/(TiOx)MnO catalysts enables CO2 reduction to CO
9-Oct-2023