ASSOCIATED CONTENT Supporting Information Gold Cluster-CeO 2 Nanostructured Hybrid Architectures as Catalysts for Selective Oxidation of Inert Hydrocarbons Yali Liu, Pengfei Zhang, Junmin Liu, Tao Wang, Qisheng Huo, Li Yang, Lei Sun,*, Zhen-An Qiao,*, and Sheng Dai *, Figure S1. UV-vis spectrum of a) Au 25 and b) Au 144 clusters in chloroform.
Figure S2. TEM a), aberration-corrected HAADF-STEM b)-c) images of Au 144 @mceo 2 nanospheres (0.2 wt % loading rate of Au 144 clusters) and the corresponding elemental mapping for Au, O, Ce of Au 144 @mceo 2 nanospheres (0.2 wt % loading rate of Au 144 clusters).
Figure S3. a) XRD patterns and b) N 2 adsorption/desorption isotherms of different Au 25 clusters loading amount on mesoporous CeO 2 nanospheres. The inset in b shows pore size distributions of samples. Figure S4. TEM images of a) Au 25 /mceo 2 b) Au 144 /mceo 2 and c) Au NPs/mCeO 2 nanospheres (the red circle areas are gold nanoparticles). d) N 2 adsorption/desorption isotherms and (inset) pore size distributions of Au NPs/mCeO 2 (black line) Au 25 /mceo 2 (blue line) and Au 144 /mceo 2 (red line). Isotherms of Au 25 /mceo 2 and Au 144 /mceo 2 have been offset by 10 and 20, respectively, along the vertical axis for clarity.
Figure S5. a) The FTIR spectra and b) TGA-MS analysis of the Au 25 @mceo 2, and Au 144 @mceo 2 nanospheres (0.2 wt % loading rate of gold clusters). Figure S6. TEM images of Au 25 @mceo 2 nanospheres (0.2 wt % loading rate of Au 25 clusters) after calcination at different temperatures a) 300 C, b) 500 C and c) 700 C, and d) the corresponding XRD patterns.
Figure S7. The reusing tests of Au 25 @mceo 2 nanospheres in the tetrahydronaphthalene oxidation. Figure S8. TEM images of a) Au 25 @mceo 2 and b) Au 144 @mceo 2 samples (0.1 wt % loading rate of gold clusters) after cyclic catalysis experiment. c) XRD patterns and d) N 2 adsorption/desorption isotherms for these samples.
Figure S9. Three-dimensional charge density difference with isosurface value of 0.00085 e/bohr3 of the Au 25 @CeO 2 system. Green and blue colors represent losing and gaining electrons, respectively. Figure S10. Optimized geometries for positive Au 25 cluster. Green color represents the middle atomic layer.
Figure S11. The reaction kinetics plots for the oxidation by 10 mg Au 25 @mceo 2 catalyst (0.1 wt % loading rate of Au 25 clusters). Reaction conditions: a) tetrahydronaphthalene 10 ml, 100 C. b) diphenylmethane 10 ml, 140 C. c) indane 10 ml, 110 C. d) ethylbenzene 10 ml, 120 C. C o : original concentration of substrate; C t : concentration of substrate at t. Table S1. C H N elemental analysis of gold clusters@mceo 2 (0.2 wt % loading rate of gold clusters) after calcination. Name N(%) C(%) H(%) S(%)
Au 25 @mceo 2 0.07 0.64 0.312 0.059 Au 144 @mceo 2 0.08 0.59 0.312 0.054 Table S2. Comparison of ethylbenzene oxidation activity of the Au 25 @mceo 2 catalysts with other reported catalytic systems. Catalyst T/P Solvent Oxidant Conversion (%) Acetophenone Selectivity (%) Phenylethyl alcohol TOF (h -1 ) references MnCO3 190 C /1MPa free O2 34.4 75.4 20.9 n.d. [32] Mn-N-C@ SiO2 120 C /0.8MPa free O2 12.8 n.d. n.d. 3,228.6 [33] Au/LDH 140 C /3MPa free TBHP 39.2 91 4 n.d. [34] CeO2 160 C /1.2MPa free TBHP 33.2 96 4 n.d. [35] Ce0.5Mn0.5Ox 120 C /10bar CH3CN O2 20.3 n.d. n.d. n.d. [38] sub-au/lc- 0.5%Pd@C- GluA-550 120 C /1atm free O2 14.2 n.d. n.d. 245 [36] CoSBA-15 80 C /1atm CH4CN TBHP 38 82.5 n.d. n.d. [37] Au25/mCeO2 120 C/1atm free O2 37.7 62 36 21,956 this work
Table S3. Aerobic oxidation of saturated hydrocarbons by gold clusters@mceo 2 (0.1 wt % loading rate of gold clusters) catalysts. Entry Catalyst Substrate Product (Sel. %) T ( C) TOF (h -1 ) Con. (%) 1 * Au 25 @mceo 2 Indane 1-Indanol (81) 1-Indanone (18) 100 32,265 43.3 2 * Au 25 @mceo 2 Indane 1-Indanol (40) 1-Indanone (52) 110 48,323 67.8 3 * Au 25 @mceo 2 Indane 1-Indanol (14) 1-Indanone (47) 120 137,195 72.6 4 * Au 144 @mceo 2 Indane 1-Indanol (74) 1-Indanone (25) 100 28,902 40.5 5 * Au 144 @mceo 2 Tetrahydronaphthalene a-naphthol (36) α-tetralone (63) 100 39,285 37.5 6 * Au 25 @mceo 2 Tetrahydronaphthalene a-naphthol (22) α-tetralone (77) 100 87,213 61.5 7 * Au 25 @mceo 2 Diphenylmethane Benzophenone (99) 140 133,912 29.7 8 * Au 144 @mceo 2 Diphenylmethane Benzophenone (99) 140 88,874 15 9 Au 25 @mceo 2 Cyclohexene 2-Cyclohexen-1-ol (33) 2-Cyclohexen-1-one (32) 100 68,849 99 Reaction conditions: * Substrate 10 ml, 10 mg of gold clusters@mceo 2 nanospheres, O 2 1 atm, 24 h; Substrate 10 ml, 10 mg of gold clusters@mceo 2, O 2 10 atm, 7 h. TOF = [reacted mol hydrocarbons]/[(total mol gold) (gold dispersion) (reaction time)]. * The TOFs were measured after the first 0.5 h of reaction. The TOFs were calculated after 7 h of the reaction. Conv., conversion; Sel., selectivity.
Table S4. Total electronic energy for Au + 25 (E atom ), O 2 binding energy to the cluster (E B ), barrier to dissociation for rate-determining step (E # ), O-O distance for O 2 (d O-O ) and net Bader charge on each O atom for reactant (N O2 ) and final product (N 2O ). E atom E b E # d O-O N O2 N 2O Au + 25 (ev/atom) (ev) (ev) (Å) (e) (e) Cluster I -2.57-0.71 0.97 1.387-0.30/-0.34-0.71/-0.67 Cluster II -2.60-0.11 1.03 1.390-0.33/-0.31-0.71/-0.71 Computational details The DFT calculation for Au 25 cluster was performed using the Vienna Ab initio Simulation Package (VASP) code, 1-2 with exchange correlation effects being described by the Perdew Burke Ernzerhof (PBE) version of the generalized gradient approximation (GGA). 3 A plane-wave basis set with kinetic-energy cutoff of 450 ev has
been used. The convergence criterion for the geometry optimizations was set to be 0.02 ev/å on force. A Monkhorst-Pack 2 2 2 k-point grid was used in our studies. For the Au 25 @CeO 2 model, CeO 2 (200) substrate consisted of 3 atomic layers (two bottom layers fixed, the other one free), the size of the surface supercell was 8 4. The Au 25 cluster was placed on the CeO 2 (200) surface. Different with the Au 25 cluster calculation, we used the PW91 type of generalized gradient approximation (GGA) 4 as the exchange correlation functional and added the simplified approach to the LSDA+U, introduced by Dudarev et al. 5 A Monkhorst-Pack 1 1 1 k-point grid was used in this calculation. To better describe the dispersion interaction within oxygen adsorption systems, van der Waals correction 6 and spin polarization were considered in the calculations. The cluster was placed in the center of a large unit cell (20 Å 20 Å 20 Å), with a vacuum space of 10 Å between each other in all directions. The climbing images nudged elastic band (CI-NEB) algorithm was employed to search for transition states (TSs). For the search TSs, the same force threshold as the geometrical optimization was used. Table S5. The gold dispersion of gold-based catalysts.
Sample Gold dispersion (%) Au 25 @mceo 2 39.9 Au 144 @mceo 2 40.8 Au 25 /mceo 2 39.1 Au 144 /mceo 2 41.4 References 1. Kresse, G.; Furthmüller, J., Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comp. Mater. Sci. 1996, 6, 15-50. 2. Kresse, G.; Hafner, J., Ab-initio molecular dynamics for liquid metals. Phys. Rev. B 1993, 47, 558-561. 3. Perdew, J. P.; Burke, K.; Ernzerhof, M., Generalized gradient approximation made simple. Phys. Rev. Lett. 1996, 77, 3865-3868. 4. Perdew J. P.; Chevary J. A.; Vosko S. H.; Jackson K. A.; Pederson M.; Singh R. D.; Fiolhais J. C., Atoms, molecules, solids, and surfaces: Applications of the
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