Synfuels China Technology Co.

Beijing, China

Synfuels China Technology Co.

Beijing, China
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Sapountzi F.M.,Syngaschem BV | Gracia J.M.,Synfuels China Technology Co. | Weststrate C.J.K.-J.,Syngaschem BV | Fredriksson H.O.A.,Syngaschem BV | And 2 more authors.
Progress in Energy and Combustion Science | Year: 2017

Water electrolysis is the most promising method for efficient production of high purity hydrogen (and oxygen), while the required power input for the electrolysis process can be provided by renewable sources (e.g. solar or wind). The thus produced hydrogen can be used either directly as a fuel or as a reducing agent in chemical processes, such as in Fischer–Tropsch synthesis. Water splitting can be realized both at low temperatures (typically below 100 °C) and at high temperatures (steam water electrolysis at 500–1000 °C), while different ionic agents can be electrochemically transferred during the electrolysis process (OH−, H+, O2−). Singular requirements apply in each of the electrolysis technologies (alkaline, polymer electrolyte membrane and solid oxide electrolysis) for ensuring high electrocatalytic activity and long-term stability. The aim of the present article is to provide a brief overview on the effect of the nature and structure of the catalyst–electrode materials on the electrolyzer's performance. Past findings and recent progress in the development of efficient anode and cathode materials appropriate for large-scale water electrolysis are presented. The current trends, limitations and perspectives for future developments are summarized for the diverse electrolysis technologies of water splitting, while the case of CO2/H2O co-electrolysis (for synthesis gas production) is also discussed. © 2016 The Authors


Birgisson S.,University of Aarhus | Shen Y.,Synfuels China Technology Co. | Iversen B.B.,University of Aarhus
Chemical Communications | Year: 2017

In operando powder X-ray diffraction data reveals an unexpected structural evolution in a layered P2 type NaxCo0.7Mn0.3O2 material during cycling. The population of single crystallographic sites sometimes increases even though sodium ions are being extracted from the structure, implying a highly cooperative diffusion mechanism. The structural evolution is shown to proceed through a series of metastable structures that cannot be predicted by thermodynamics. © The Royal Society of Chemistry.


Wang J.,CAS Institute of Mechanics | Ma J.,Nanjing Southeast University | Ni Z.,Nanjing Southeast University | Zhang L.,Synfuels China Technology Co. | Hu G.,CAS Institute of Mechanics
RSC Advances | Year: 2014

Recent experimental studies showed that the access resistance (AR) of a nanopore with a low thickness-to-diameter aspect ratio plays an important role in particle translocation. The existing theories usually only consider the AR without the presence of particles in the pore systems. Based on the continuum model, we systematically investigate the current change caused by nanoparticle translocation in different nanopore configurations. From numerical results, an analytical model is proposed to estimate the influence of the AR on the resistive-pulse amplitude, i.e., the ratio of the AR to the pore resistance. The current change is first predicted by our model for nanoparticles and nanopores with a wide range of sizes at the neutral surface charge. Subsequently, the effect of surface charges is studied. The results show that resistive-pulse amplitude decreases with the increasing surface charge of the nanoparticle or the nanopore. We also find that the shape of the position-dependent resistive-pulse might be distorted significantly at low bulk concentration due to concentration polarization. This study provides a deep insight into the AR in particle-pore systems and could be useful in designing nanopore-based detection devices. © 2014 The Royal Society of Chemistry.


PubMed | University of Aarhus and Synfuels China Technology Co.
Type: | Journal: Chemical communications (Cambridge, England) | Year: 2017

In operando powder X-ray diffraction data reveals an unexpected structural evolution in a layered P2 type Na


Bu Y.,TU Eindhoven | Niemantsverdriet J.W.H.,Syngaschem BV | Niemantsverdriet J.W.H.,Synfuels China Technology Co. | Fredriksson H.O.A.,TU Eindhoven | Fredriksson H.O.A.,Syngaschem BV
ACS Catalysis | Year: 2016

The oxidation state of Cu nanoparticles during CO oxidation in CO + O2 gas mixtures was sensitively monitored via localized surface plasmon resonances. A microreactor, equipped with in situ UV-vis and mass spectrometry, was developed and used for the measurements. Cu nanoparticles of ∼30 nm average diameter were supported on optically transparent, planar quartz wafers. The aim of the study is 2-fold: (i) to demonstrate the performance and usefulness of the setup and (ii) to use the combined strength of model catalysts and in situ measurements to investigate the correlation between the catalyst oxidation state and its reactivity. Metallic Cu is significantly more active than both Cu(I) and Cu(II) oxides. The metallic Cu phase is only maintained under conditions where close to full oxygen conversion is achieved. This implies that kinetic measurements, aimed at determining the apparent activation energy for metallic Cu under realistic steady-state conditions, are difficult or impossible to perform. © 2016 American Chemical Society.


Lim T.,Syncat at Beijing | Niemantsverdriet J.W.H.,Synfuels China Technology Co. | Gracia J.,Syncat at Beijing
ChemCatChem | Year: 2016

We have performed an in-depth abinitio study of the magnetic structure within the most active perovskites for the oxygen evolution reaction. In all cases, the ground state exhibits an extended antiferromagnetic coupling in the unit cell. Layered antiparallel alignment of the magnetic moments appears to be related to their electrocatalytic activity. All the perovskites calculated within this paper show space-separated charge-transport channels depending on the spin orientation. Comparing the electronic structures with the reported activities, we find a direct correlation between the magnetic accumulation on the spin channels in the bulk material and the catalytic activity. We discuss the possible implications of such observations in terms of magnetic interactions. During oxygen evolution in water electrolysis, reactants and products do not preserve spin. For triplet state oxygen to evolve, the catalyst at the anode can speed up the reaction if it is able to balance the magnetism of the oxygen molecule by extracting electrons with an opposite magnetic moment, conserving the overall spin. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Weststrate C.J.,Syngaschem BV | van de Loosdrecht J.,Sasol Limited | Niemantsverdriet J.W.,Syngaschem BV | Niemantsverdriet J.W.,Synfuels China Technology Co.
Journal of Catalysis | Year: 2016

The present article summarizes experimental findings of the interaction of CO with single crystal surfaces of cobalt. We first provide a quantitative study of non-dissociative CO adsorption on Co(0001) and establish a quantitative correlation between θCO and adsorption site occupation. In light of these findings we revisit the structure of previously reported ordered CO/Co(0001) adsorbate layers. Measurements of the CO coverage at equilibrium conditions are used to derive a phase diagram for CO on Co(0001). For low temperature Fischer-Tropsch synthesis conditions the CO coverage is predicted to be ≈0.5 ML, a value that hardly changes with pCO. The CO desorption temperature found in temperature programmed desorption is practically structure-independent, despite structure-dependent heats of adsorption reported in the literature. This mismatch is attributed to a structure-dependent pre-exponential factor for desorption. IR spectra reported throughout this study provide a reference point for IR studies on cobalt catalysts. Results for CO adsorbed on flat and defect-rich Co surfaces as well as particular, CO adsorbed on top sites, and in addition affect the distribution of COad over the various possible adsorption sites. © 2016 Elsevier Inc.


Lim T.,Synfuels China Technology Co. | Niemantsverdriet J.W.H.,Synfuels China Technology Co. | Niemantsverdriet J.W.H.,Syngaschem BV | Gracia J.,Synfuels China Technology Co.
ChemCatChem | Year: 2016

We have performed an in-depth ab initio study of the magnetic structure within the most active perovskites for the oxygen evolution reaction. In all cases, the ground state exhibits an extended antiferromagnetic coupling in the unit cell. Layered antiparallel alignment of the magnetic moments appears to be related to their electrocatalytic activity. All the perovskites calculated within this paper show space-separated charge-transport channels depending on the spin orientation. Comparing the electronic structures with the reported activities, we find a direct correlation between the magnetic accumulation on the spin channels in the bulk material and the catalytic activity. We discuss the possible implications of such observations in terms of magnetic interactions. During oxygen evolution in water electrolysis, reactants and products do not preserve spin. For triplet state oxygen to evolve, the catalyst at the anode can speed up the reaction if it is able to balance the magnetism of the oxygen molecule by extracting electrons with an opposite magnetic moment, conserving the overall spin. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


Chen X.,CAS Institute of Mechanics | Xue C.,CAS Institute of Mechanics | Zhang L.,Synfuels China Technology Co. | Hu G.,CAS Institute of Mechanics | And 2 more authors.
Physics of Fluids | Year: 2014

The microfluidic inertial effect is an effective way of focusing and sorting droplets suspended in a carrier fluid in microchannels. To understand the flow dynamics of microscale droplet migration, we conduct numerical simulations on the droplet motion and deformation in a straight microchannel. The results are compared with preliminary experiments and theoretical analysis. In contrast to most existing literature, the present simulations are three-dimensional and full length in the streamwise direction and consider the confinement effects for a rectangular cross section. To thoroughly examine the effect of the velocity distribution, the release positions of single droplets are varied in a quarter of the channel cross section based on the geometrical symmetries. The migration dynamics and equilibrium positions of the droplets are obtained for different fluid velocities and droplet sizes. Droplets with diameters larger than half of the channel height migrate to the centerline in the height direction and two equilibrium positions are observed between the centerline and the wall in the width direction. In addition to the well-known Segré-Silberberg equilibrium positions, new equilibrium positions closer to the centerline are observed. This finding is validated by preliminary experiments that are designed to introduce droplets at different initial lateral positions. Small droplets also migrate to two equilibrium positions in the quarter of the channel cross section, but the coordinates in the width direction are between the centerline and the wall. The equilibrium positions move toward the centerlines with increasing Reynolds number due to increasing deformations of the droplets. The distributions of the lift forces, angular velocities, and the deformation parameters of droplets along the two confinement direction are investigated in detail. Comparisons are made with theoretical predictions to determine the fundamentals of droplet migration in microchannels. In addition, existence of the inner equilibrium position is linked to the quartic velocity distribution in the width direction through a simple model for the slip angular velocities of droplets. © 2014 AIP Publishing LLC.


The present invention discloses a transition metal nano-catalyst, a method for preparing the same, and a process for Fischer-Tropsch synthesis using the catalyst. The transition metal nano-catalyst comprises transition metal nanoparticles and polymer stabilizers, and the transition metal nanoparticles are dispersed in liquid media to form stable colloids. The transition metal nano-catalyst can be prepared by mixing and dispersing transition metal salts and polymer stabilizers in liquid media, and then reducing the transition metal salts with hydrogen at 100-200 C. The process for F-T synthesis using the nano-catalyst comprises contacting a reactant gas mixture comprising carbon monoxide and hydrogen with the catalyst and reacting. In addition, the transition metal nanoparticles have smaller diameter and narrower diameter distribution, which is beneficial to control product distribution. Meanwhile, the catalyst can be easily separated from hydrocarbon products and reused.

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