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| 1 | High population and dispersion of pentacoordinated Al~Ⅴ species on the surface of ?ame-made amorphous silica-alumina显示文摘Pentacoordinated Al(Al~Ⅴ)species in silica-alumina are promising to promote the formation of acid sites or act as surface defects for tailoring single-atom catalysts.However,pentahedral coordination(Al~Ⅴ)is rarely observed in conventionally prepared silica-alumina.Here,we show that high population and dispersion of Al~Ⅴ species on the surface of amorphous silica-alumina(ASA)can be achieved by means of flame spray pyrolysis.High resolution TEM/EDX,high magnetic-field NMR and DFT calculations are employed to characterize the structure of as-prepared ASAs.Solid-state ^(27)Al multi-quantum MAS NMR experiments show that most of the Al~Ⅴspecies are formed independently from the alumina phase and are accessible for guest molecules on the surface.Upon water adsorption,these Al~Ⅴ species are transformed to Al~Ⅵ species,structurally similar to surface Al~Ⅳ species,as confirmed by DFT calculations.The outstanding catalytic activity of as-synthesized ASA is demonstrated using the in situ H/D exchange reaction with deuterated benzene as an example.The Al~Ⅴ-rich ASA provides a much lower activation energy(~30 kJ/mol)than that reported for zeolite H-ZSM-5(~60 kJ/mol).The superior catalytic performance is attributed to the high Al~Ⅴcontent promoting the surface active sites in ASA.The knowledge gained on the synthesis of Al~Ⅴ-rich ASAs and the nature of aluminum coordination in these materials could pave the way to more efficient silica-alumina based catalysts. | Zichun Wang Yijiao Jiang Xianfeng Yi Cuifeng Zhou Aditya Rawal James Hook Zongwen Liu Feng Deng Anmin Zheng Michael Hunger Alfons Baiker Jun Huang | 2019 | Science Bulletin2019，64，8： | 2 |
| 2 | Continuous dimethyl carbonate synthesis from CO_(2) and methanol over Bi_(x)Ce_(1-x)O_(δ) monoliths:Effect of bismuth doping on population of oxygen vacancies,activity,and reaction pathway显示文摘We evaluated bismuth doped cerium oxide catalysts for the continuous synthesis of dimethyl carbonate(DMC)from methanol and carbon dioxide in the absence of a dehydrating agent.Bi_(x)Ce_(1-x)O_(δ)nanocomposites of various compositions(x=0.06-0.24)were coated on a ceramic honeycomb and their structural and catalytic properties were examined.The incorporation of Bi species into the CeO_(2) lattice facilitated controlling of the surface population of oxygen vacancies,which is shown to play a crucial role in the mechanism of this reaction and is an important parameter for the design of ceria-based catalysts.The DMC production rate of the Bi_(x)Ce_(1-x)O_(δ) catalysts was found to be strongly enhanced with increasing Ov concentration.The concentration of oxygen vacancies exhibited a maximum for Bi_(0.12)Ce_(0.88)O_(δ),which afforded the highest DMC production rate.Long-term tests showed stable activity and selectivity of this catalyst over 45 h on-stream at 140°C and a gas-hourly space velocity of 2,880 mL·g_(cat)^(-1)·h^(-1).In-situ modulation excitation diffuse reflection Fourier transform infrared spectroscopy and first-principle calculations indicate that the DMC synthesis occurs through reaction of a bidentate carbonate intermediate with the activated methoxy(-OCH_(3))species.The activation of C0_(2) to form the bidentate carbonate intermediate on the oxygen vacancy sites is identified as highest energy barrier in the reaction pathway and thus is likely the rate-determining step. | Yongdong Chen Yue Li Wei Chen Wen Wu Xu Zhong-kang Han Ammara Waheed Zhongbin Ye Gao Li Alfons Baiker | 2022 | Nano Research2022，15，2： | 2 |
| 3 | Selective Oxidation Catalysis: Opportunities and Challenges显示文摘 | Ive Hermans Eyal S. Spier Ulrich Neuenschwander Natascia Turrà Alfons Baiker | 2009 | Topics in Catalysis2009，，9： | 1 |
| 4 | Preparation of supported gold catalysts for low-temperature CO oxidation via 'size-controlled' gold colloids 显示文摘 | Grunwaldt J D Kiener C WSgerbauer C Baiker Alfons | 1999 | Journal of Catalysis1999，181，： | 1 |
| 5 | Catalytic synthesis of higher aliphatic amines from the corresponding alcohols 显示文摘 | Alfons Baiker Jacek Kijenski | 1985 | Catal Rev Sci1985，27，4： | 1 |
| 6 | Cobalt-catalyzed amination of 1,3-cyclohexanediol and 2, 4-pentanediol in supercritical ammonia显示文摘 | Gregor Jenzer Tammas Mallat Alfons Baiker | 1999 | Catalysis Letters1999，61，： | 1 |
| 7 | Aerogels in catalysis显示文摘 | Alfons Baiker | 1995 | Catal Rev1995，37，9： | 1 |
| 8 | Combustion of methane over palladium/zirconia: effect of Pd-particle size and role of lattice oxygen显示文摘 | Christian A. Müller Marek Maciejewski René A. Koeppel Alfons Baiker | 1999 | Catalysis Today1999，，1： | 1 |
| 9 | Dehydrogenation of Methylcyclohexane to toluene in a pilot-scale membrane reactor 显示文摘 | Jawad K Ali Alfons Baiker | 1997 | Applied catalysis A: General1997，155，1： | 1 |
| 10 | A simple preparation of an efficient heterogeneous gold catalyst for aerobic amine oxidation 显示文摘 | Linda Aschwanden Tamas Mallat Frank Krumeich Alfons Baiker | 2009 | Journal of Molecular Catalysis A: Chemical2009，309，12： | 1 |
| 11 | Combustion of Methane over Palladium/Zirconia Derived from a Glassy Pd–Zr Alloy: Effect of Pd Particle Size on Catalytic Behavior显示文摘 | Christian A. Müller Marek Maciejewski René A. Koeppel Alfons Baiker | 1997 | Journal of Catalysis1997，，1： | 1 |
| 12 | Ionic liquids and dense carbon dioxide:A beneficial biphasic system for catalysis显示文摘 | Jutz Fabian Andanson Jean-Michel Baiker Alfons | 2011 | Chemical Reviews2011，111，： | 1 |
| 13 | Catalytic synthesis of higher aliphatic amines from the corresponding alcohols 显示文摘 | Alfons Baiker Jacek Kijenski | 1985 | Catalysis Reviews - Science and Engineering1985，27，4： | 1 |
| 14 | Nanostructured Ni-MoCx:An efficient non-noble metal catalyst for the chemoselective hydrogenation of nitroaromatics显示文摘Catalysts for chemoselective hydrogenation are of vital importance for the synthesis of various important chemicals and intermediates.Herein we developed a simple method for preparing a highly efficient Ni-MoC_(x)nanocomposite catalyst via temperature-programmed carburization of a polyoxometalate precursor.X-ray diffraction(XRD),scanning transmission electron microscopy(STEM),X-ray photoelectron spectroscopy(XPS),and X-ray absorption spectroscopy(XAS)analyses indicate that the resulting mesoporous nanocomposite catalyst is made up of well-dispersed metallic nickel particles embedded in a MoC_(x)matrix.This catalyst exhibits high activity and selectivity(>99%)in the hydrogenation of various substituted nitroaromatics to corresponding anilines.The high efficiency is attributed to the intimate contact of the constituents favoring electron transfer and hydrogen adsorption.Dihydrogen is physisorbed on the carbide support and dissociates on the nickel particles,as evidenced by Mo K-edge X-ray absorption near-edge structure(XANES)spectra,density functional theory(DFT),and hydrogen-deuterium exchange.The remarkable catalytic performance of the catalyst could be traced back to the synergistic interaction between the Ni particles and the carbide support.In-situ infrared spectroscopy and DFT simulations indicated that the adsorption/activation of the nitro group is favored compared to that of other substituents at the aromatic ring.In recyclability tests,the Ni-MoC_(x)nanocomposite showed no significant loss of catalytic performance in seven consecutive runs,indicating its robust nature. | Yifei Zhang Zhiwen Li Jingjing Zhang Liangliang Xu Zhong-Kang Han Alfons Baiker Gao Li | 2023 | Nano Research2023，16，7： | 1 |
| 15 | 显示文摘 | | 1999 | Chemical Reviews1999，99，2： | 1 |
| 16 | A new mesoporous hybrid material: porphyrin-doped aaerogel as a catalyst for the epoxidation of olefins显示文摘 | Muriel Bonnet Leo Schmid Alfons Baiker | 2002 | Adv Funct Mater2002，12，1： | 1 |
| 17 | Supercritical fluids in heterogeneous cataly- sis 显示文摘 | Alfons Baiker | 1999 | Chemical Reviews1999，99，2： | 1 |
| 18 | Zirconia aerogels:effect of acid-to-alkoxide ratio,alcoholic solvent and supercritical drying on structural properties显示文摘 | Carsten Stocker Alfons Baiker | | 0，，： | 1 |
| 19 | Simple preparation routes towards novel Zn-based catalysts for the solventless synthesis of propylene carbonate using dense carbon dioxide显示文摘 | Michael Ramin Niels van Vegten Jan-Dierk Grunwaldt Alfons Baiker | 2006 | Journal of Molecular Catalysis A Chemical2006，，1： | 1 |
| 20 | Zirconia aerogels:effect of acid-to-alkoxide ratio,alcoholic solvent and supercritical drying method on structural peoperties显示文摘 | Alfons Baiker | 1998 | Journal of Non-Crystalline Solides1998，223，： | 1 |
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