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[Display omitted] • CO 2 hydrogenation over inverse supported Zr 9 O 18 /Ni(1 1 1) nanocatalyst was computed. • Charge transfer from Ni(1 1 1) to supported Zr 9 O 18 nanoparticle has been found. • Supported Zr 9 O 18 nanoparticle has coordinatively unsaturated Zr sites at interface. • H 2 prefers dissociative adsorption on Ni(1 1 1) and CO 2 activation prefers interface Zr sites. • Surface HCOO is the most important intermediate and methanol is the selective product. To tune the activity and selectivity of CO 2 hydrogenation, inverse supported Zr 9 O 18 /Ni(1 1 1) catalysts are designed based on ab initio molecular dynamics simulation and density functional theory calculation under the consideration of the number of interfacial O and Zr atoms as well as the interaction between O and Zr atoms. For the most stable catalyst with coordinatively unsaturated interface Zr sites, charge transfer from surface to oxide has been found. The Ni(1 1 1) surface is pre-covered by H atoms and the interface Zr sites can activate CO 2 to a large extent, and their interaction results in the spontaneous formation of surface formate. Further hydrogenation of surface formate leads to the selective formation of methanol with an apparent Gibbs free energy barrier of 0.62 eV, lower than that of methane formation (1.09 eV). On the contrary to metallic nickel and supported nickel catalysts, the most favoured methanol formation route [HCOO → CHO → CH 2 O → CH 3 O → CH 3 OH] does not involve CO as intermediate, revealing the mediated interface effect. [ABSTRACT FROM AUTHOR]

[Display omitted] • CO 2 Conversion to CH 4 and CH 3 OH on ZrO 2 support Ni catalysis was computed. • Metal-Metal and Metal-support Interaction was analysed. • Reaction Mechanisms, differently from metallic Ni, were identified. • Metal interaction determines structure of support Ni and reaction mechanisms. To better understand the metal-support interaction and structure–activity relationship, we computed the mechanisms of CO 2 hydrogenation to CH 4 and CH 3 OH on ZrO 2 supported Ni catalyst. On a supported irregular Ni 13 cluster, which exhibits a balanced metal–metal and metal-support interaction with surface Zr and O atoms covered, two preferred routes [CO 2 → CO → CHO → CH/CH 3 O → CH 3 → CH 4 /CH 3 OH] are found, and the rate-determining step is the CO 2 direct dissociation. Such mechanisms differ very strongly from those reported on flat metallic Ni(1 1 1) surface and Ni clusters supported on different metal oxides, demonstrating that different supports generate different metal-support interaction that simultaneously changes the metal structures and the reaction mechanisms. [ABSTRACT FROM AUTHOR]

The CO 2 formation mechanism on Fe x C y and its structure–reactivity relationship during sintering process were systemically elucidated using the ReaxFF. [Display omitted] • Investigate the structure-activity relationship of different Fe-based nanoparticles in the sintering process. • Formation of low-coordination-number atoms may be the real reason for promoted TOF of the sintering structures. • The increased amplitude of surface area of sintered Fe x C y varies with its content of carbon. • The main CO 2 formation varies with the Fe x C y : Eley-Rideal VS. Langmuir-Hinshelwood mechanism. The sintering of nanostructured catalysts poses a grand challenge in understanding the complex mechanism in the experimental phenomena, as well as the structure-activity relationship. Here, we systematically investigate the structure-activity relationship of sintered Fe-based catalysts, including Fe 2 C, Fe 5 C 2 , Fe 3 C and pure Fe, in the CO activation by reactive molecular dynamics simulations. The results show that the sintering structures can promote the turn-over frequency of Fe 3 C compared with its un-sintered near-size structures, which might be attributed to the formation of low-coordination-number atoms. The change of surface area shows a similar trend for Fe x C y and pure Fe, and its increased magnitude varies with the content of carbon in the Fe x C y bulk. For size effect, the Fe 2 C displays the largest turn-over frequency for the 4.34 nm particle. The CO 2 formation mechanism has also been compared for different Fe x C y , which may provide critical theoretical insights for industrial reduction of CO 2 emission. [ABSTRACT FROM AUTHOR]