Publications by authors named "Penny Xiao"

The traditional CO hydrogenation reaction in gas phase always requires harsh reaction conditions to activate CO , resulting in huge energy consumption. However, with the assistance of 1-butanol solvent, catalytic CO hydrogenation can be proceeded at a mild condition of 170 °C and 30 bars. To further improve the catalytic performance of the widely studied Cu-ZnO-ZrO catalyst (CZZ), the catalysts were modified by incorporating hydrotalcite (HTC) as a support material.

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Direct electrochemical reduction of CO to C products such as ethylene is more efficient in alkaline media, but it suffers from parasitic loss of reactants due to (bi)carbonate formation. A two-step process where the CO is first electrochemically reduced to CO and subsequently converted to desired C products has the potential to overcome the limitations posed by direct CO electroreduction. In this study, we investigated the technical and economic feasibility of the direct and indirect CO conversion routes to C products.

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We reported a new polymorphous core-shell metal-organic framework (MOF) in the form of a three-dimensional MOF core wrapped in a two-dimensional layered MOF shell by applying a general acid-solvent synergy synthesis. This hybrid material can achieve high adsorptive selectivity/capacity simultaneously, which is validated by the unary isotherms of CO and N conducted at 273 K (0-1 bar). The MOF-S@MOF-C with a 7-day exchange showed the highest CO/N selectivity (32.

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We report a synthetic strategy for constructing a novel flexible MOF from a rigid parent structure by ligand exchange. This is the first reported study on introducing flexible heterogeneity into a rigid structure via substantial structural rearrangement. The daughter material exhibits enhanced gas separation selectivity compared with the parent.

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The crucial role of dispersion force in correctly describing the adsorption of some typical small-size gas molecules (e.g., CO2, N2, and CH4) in ion-exchanged chabazites has been investigated at different levels of theory, including the standard density functional theory calculation using the Perdew, Burke, and Ernzerhof (PBE) exchange-correlation functional and van der Waals density functional theory (vdWDFT) calculations using different exchange-correlation models - vdW_DF2, optB86b, optB88, and optPBE.

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We report an unusual operating regime for a chabazite zeolite in which the adsorption selectivity for N2 over CH4 inverts from being more selective for N2 at 253 K, to becoming less selective with increasing temperature and eventually becoming selective for CH4 over N2 above 293 K.

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ETS-4 and ETS-10 titanosilicates were prepared from fly ash and anatase, as silica and titanium sources respectively, via a hydrothermal procedure for the first time. The fusion of fly ash by alkali was carried out at a relatively low temperature and the use potassium fluoride salt was avoided in the synthesis of ETS. The by-product of this process is mainly NaCl, which is a useful source material for industry.

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Adsorption equilibria of a CO2/H2O binary mixture on activated alumina F-200 were measured at several temperatures and over a wide range of concentrations from 4% to around 90% of the saturated water vapor pressure. In comparison with the single-component data, the loading of CO2 was not reduced in the presence of H2O, whereas at low relative humidity the adsorption of H2O was depressed. The binary system was described by a competitive/cooperative adsorption model where the readily adsorbed water layers acted as secondary sites for further CO2 adsorption via hydrogen bonding or hydration reaction.

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