Erik Fridell

• IVL Swedish Environmental Research Institute

Marine pollution management requires identifying all sources of contaminants, yet shipping's role in marine contamination remains unexplored. To address this gap, we investigated shipping contribution to water and air pollutant loads in the Northern Adriatic Sea in 2018 and under two future scenarios. The approach integrated (i) modelled data of sh...

Shipping is responsible for a range of different pressures affecting air quality, climate, and the marine environment. Most social and economic analyses of shipping have focused on air pollution assessment and how shipping may impact climate change and human health. This risks that policies may be biased towards air pollution and climate change, wh...

In response to stricter regulations on ship air emissions, many shipowners have installed exhaust gas cleaning systems, known as scrubbers, allowing for use of cheap residual heavy fuel oil. Scrubbers produce large volumes of acidic and polluted water that is discharged to the sea. Due to environmental concerns, the use of scrubbers is being discus...

EU recently decided to include shipping, meaning all intra-European shipping and 50% of extra-European voyages, in the EU Emissions Trading System (ETS) beginning in 2024. This article provides an early assessment of the impacts of the EU ETS on the shipping sector’s potential reductions in greenhouse gas emissions for different types of ships. It...

The lifecycle greenhouse gas (GHG) emissions (Well-to-Wake) from maritime transport must be reduced by at least 50% in absolute values by 2050 to contribute to the ambitions of the Paris Agreement (2015). A transition from conventional fuels to alternative fuels with zero or lower GHG emissions is viewed as the most promising avenue to reach the GH...

The European Green Deal from the European Commission in 2019 set a high aim: that EU will become climate neutral by 2050. As a part of this, the European Commission proposed that the EU Emission Trading System (ETS), is extended to include the maritime sector. This report assesses different design features of shipping in ETS, analyse the impact on...

We present a new concept for marine research, applied in the EU-funded project EMERGE, “Evaluation, control and Mitigation of the EnviRonmental impacts of shippinG Emissions” (2020–2024; https://emerge-h2020.eu/). For the first time, both the various marine and atmospheric impacts of the shipping sector have been and will be comprehensively analyze...

Shipping is an important source of pollution affecting both atmospheric and aquatic environments. To allow for efficient mitigation of environmental degradation, it is essential to know the extent of the impacts of shipping in relation to other sources of pollution. Here, we give a perspective on a holistic approach to studies of the environmental...

The climate impact caused by the shipping industry has increased over the past decades despite attempts to improve the energy efficiency of vessels and lower induced emissions. A tool in reducing climate and other environmental impacts is new low emissions propulsion technologies. These new technologies need to reduce harmful emissions not only in...

This policy brief identifies and discusses key design features for including shipping in the EU ETS and assesses modal split impacts and economic implications.The ambition has not been to provide recommendations but rather an overview and brief assessment of the options that have been part of the discussion pending the final legislative proposal.

Shipping is an activity responsible for a range of different pressures affecting the marine environment, air quality and human welfare. The methodology on how ship emissions impact air quality and human health are comparatively well established and used in cost-benefit analysis of policy proposals. However, the knowledge base is not the same for im...

The activities and emissions from leisure boats in the Baltic Sea have been modeled in a comprehensive approach for the first time, using a new simulation model leisure Boat Emissions and Activities siMulator (BEAM). The model utilizes survey data to characterize the national leisure boat fleets. Leisure boats have been categorized based on their s...

Emissions of exhaust gases and particulate matter from a dual fuel marine engine using methanol as fuel with marine gasoil as pilot fuel have been examined for a ferry during operation. The emission factor for nitrogen oxides is lower than what is typically found for marine gasoil but does not reach the tier III limit. The emissions of particulate...

Mandatory speed reductions have been proposed by different parties within the International Maritime Organization (IMO) as a short time measure to reduce the emissions of greenhouse gases from shipping. This study assesses what consequences it can have for Swedish shipowners and the Swedish business society that relies on maritime transportation in...

Shipping is an important source of air pollutants, from the global to the local scale. Ships emit substantial amounts of sulfur dioxides, nitrogen dioxides, and particulate matter in the vicinity of coasts, threatening the health of the coastal population, especially in harbour cities. Reductions in emissions due to shipping have been targeted by s...

The aim of this project is to assess the overall design and consequences of including maritime transports in the EU emission trading scheme (EU ETS) - the main joint EU policy for reducing greenhouse gases (GHG) emissions. This has been proposed in the Directive 2018/410 with a timeline to year 2023, to await IMO acting on implementing measures to...

There is an increase in installations of exhaust gas scrubbers on ships following international regulations on sulphur content in marine fuel from 2020. We have conducted emission measurements on a four-stroke marine engine using low sulphur fuel oil (LSFO) and heavy fuel oil (HFO) at different steady state engine loads. For the HFO the exhaust was...

To reduce the climate impact of shipping, the introduction of alternative fuels is required. There is a range of different marine fuel options but ammonia, a potential zero carbon fuel, has recently received a lot of attention. The purpose of this paper is to assess the prospects for ammonia as a future fuel for the shipping sector in relation to o...

Abstract. Shipping is an important source of air pollutants, from the global to the local scale. Ships are emitting substantial amounts of sulphur dioxides, nitrogen dioxides and particulate matter in the vicinity of coasts, threatening the health of the coastal population, especially in harbour cities. Reductions of emissions due to shipping have...

Abstract. The activities and emissions from leisure boats at the Baltic Sea have been modelled in a comprehensive approach for the first time, using a new simulation model leisure boat emissions and activities simulator (BEAM). The model utilizes survey data to characterize the national leisure boat fleets. Leisure boats have been categorized based...

Commercial shipping fleet and its emissions can be modeled in detail, but the emission from leisure craft are often invisible for activity based, bottom-up emission inventories. A new model (FMI-BEAM) describes the emissions from the leisure craft fleet in the Baltic Sea area, complementing the existing STEAM emission modeling suite. BEAM combines...

Long-term scenario analyses can be powerful tools to explore plausible futures of human development under changing environmental, social, and economic conditions and to evaluate implications of different approaches to reduce pollution and resource overuse. Vulnerable ecosystems like the Baltic Sea in North-Eastern Europe tend to be under pressure f...

Air pollution due to shipping is a serious concern for coastal regions in Europe. Shipping emissions of nitrogen oxides (NOx) in air over the Baltic Sea are of similar magnitude (330 ktyr-1) as the combined land-based NOx emissions from Finland and Sweden in all emission sectors. Deposition of nitrogen compounds originating from shipping activities...

The main purpose of this paper is to analyse the socio-economic justification of implementing a Nitrogen Emission Control Area (NECA), starting 2021, for ships in the Baltic Sea and/or the North Sea and English Channel. We analyse the potential for emission reduction, emission control costs, and monetised benefits following the introduction of a NE...

The fuel sulfur content in marine fuels has been regulated in Sulfur Emission Control Areas (SECAs) since January 2015. However, other fuel characteristics are also believed to have an impact on particle emissions, particularly on the number of particles emitted. This study investigates the impact of the content of aromatics in fuel. To achieve fue...

Through the international work carried out recently by International Maritime Organization Marine Environment Protection Committee, the need for improved selective catalytic reduction systems for marine applications at low and transient temperatures has been acknowledged. It is of importance to improve the low-temperature activity to achieve compli...

Climate change has recently received more attention in the shipping sector. This is mainly due to a growing demand for reduced global emissions and the fact that shipping is one of the fastest growing sectors in terms of greenhouse gas (GHG) emissions. In parallel, ports have started to introduce programmes and policies to address these emissions....

Measurements of particle number and mass concentrations and number size distribution of particles from a ship running on liquefied natural gas (LNG) were made on-board a ship with dual-fuel engines installed. Today there is a large interest in LNG as a marine fuel, as means to comply with sulphur and NOX regulations. Particles where studied in a wi...

Particle emissions from a marine diesel engine operating at low loads with four different fuels were characterized with respect to particle number (PN) and particle mass (PM), size distribution, volatility and chemical composition. The four different fuels used were Swedish Environmental class 1 (MK1) and class 3 diesel (MK3), heavy fuel oil (HFO,...

Measurements of exhaust gases from a marine engine equipped with an open-loop wet scrubber using seawater for sulphur dioxide (SO2) abatement are reported. The scrubber reduces the SO2 emissions effectively to levels corresponding to <0.1% S in the fuel (the level that applies to sulphur emission control areas from 2015). The scrubber also reduces...

The combined effort of reducing the emissions of sulphur dioxide, nitrogen oxides and greenhouse gases to comply with future regulations and reduce impact on climate change will require a significant change in ship propulsion. One alternative is to change fuels. In this study we compare the life cycle environmental performance of liquefied natural...

The approaching marine fuel sulphur regulations will result in reductions in emissions of sulphur oxides to air. Importantly, also particle emissions that impose health risks will be lessened by these regulations. Combustion particles from marine engines are complex mixtures of organic compounds, soot, sulphate, metals and other inorganic species....

Alternative fuels are becoming more and more important for road traffic and one fuel that has been used for several years is ethanol (E85). The main discussion points regarding the environmental performance for ethanol as a fuel are related to the production. However, there are also some notable differences in the emissions between E85 and petrol f...

The effect of sulfur, water, and varying NO/NO2 concentrations on the NOx reduction over a commercial urea-SCR catalyst for marine applications was studied. A system approach where reaction temperature, gas flow, and gas feed composition was considered. In the presence of both SO2 and water, the activity for NOx reduction decreased, in particular a...

Emissions of particulate matter (PM) from shipping contribute significantly to the anthropogenic burden of PM. The environmental effects of PM from shipping include negative impact on human health through increased concentrations of particles in many coastal areas and harbour cities and the climate impact. The PM emitted by ship engines consists of...

Short sea shipping is facing harder requirements on exhaust emissions in the coming years as stricter regulations are enforced in some regions of the world. In addition, shortage of conventional fuels as well as restrictions on greenhouse gas emissions makes the search for new fuels of interest. The objective of this article is to assess important...

The upcoming stricter emission control area (ECA) regulations on sulphur and nitrogen oxides (NOX) emissions from shipping can be handled by different strategies. In this study, three alternatives complying with the ECA regulations for sulphur as well as Tier III for NOX are presented and compared using life cycle assessment. None of the three alte...

This paper provides an overview of several parameters that would improve the fuel efficiency of shipping. Calculations are carried out from a Latin American perspective, and illustrate the emissions to air and the fuel consumed by different transport modes. One of the conclusions is that initiatives and incentives to improve energy efficiency in th...

In this study nanoparticle emissions have been characterised on-board a ship with focus on number, size and volatility. Measurements were conducted on one of the ship's four main 12 600 kW medium-speed diesel engines which use low sulphur marine residual fuel and have a Selective Catalytic Reduction (SCR) system for NO(X) abatement. The particles w...

The goal of this study is to evaluate the life cycle performance of two alternative pathways to biofuels in the shipping industry: the ‘diesel route’ and the ‘gas route’. The diesel route comprises of a shift from heavy fuel oil to marine gas oil and then a gradual shift to biodiesel, whereas the gas route comprises of a shift to liquefied natural...

This study investigates how sulfur affects the NOx reduction activity over a commercial vanadium based urea-SCR catalyst for marine applications, especially at low temperatures, and in combination with H2O. The addition of SO2 in the absence of H2O promotes the NOx reduction at 350°C, while the addition of H2O, in the absence of SO2, gives rise to...

The negative impacts of transport are in general associated with costs. These costs are usually denoted as ‘external costs’ or ‘externalities’. This paper presents a tool for calculating external costs for freight transport together with its application to a number of case studies. The categories considered include: air pollution, greenhouse gases,...

Air emissions from shipping have received attention in recent years and the shipping industry is striving for solutions to reduce their emissions and to comply with stricter regulations. Strategies to reduce emissions can consist of a fuel switch, engine changes, or end-of-pipe technologies, but they do not necessarily imply reduced life cycle emis...

We report tunnel measurements, where abrasion particles from different types of trains are measured in two situations and emission factors are calculated from these. The measurements show significantly elevated particle concentrations in train passages that last for about a minute and are accompanied by increased airflow. The emission of particles...

Ship exhausts contain high levels of particles and nitrogen oxides due to the heavy fuel oil normally used for combustion and the combustion characteristics of most ship engines. The quantification of exhaust gases during ships’ manoeuvring has not received a lot of attention. This work presents results from emission measurements for the main engin...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Mytilus edulis foot protein 1 (Mefp-1) contains the redox-functional amino acid 3,4-dihydroxyphenylalanine (DOPA), which is a typical feature of most mefp proteins. We have previously shown, using combined optic (ellipsometry) and acoustic (QCM-D) measurements, that the oxidizing agent sodium periodate (NaIO4) and the transition metal ion Cu2+ prom...

A number of measurements of particle emission from railways are presented. The measurements featured a particle instrument mounted in a compartment under a Regina train. The particles were probed in a volume between the coaches. The measurements were done in two campaigns and provide information on how the particle emissions vary with driving patte...

This paper presents the results of field emission measurements that have been carried out on the 4500-kW four-stroke main engine on-board a product tanker. Two fuel qualities--heavy fuel oil (HFO) and marine gas oil (MGO)-have been tested on the same engine for comparable load settings. A fuel switch within the marine sector is approaching and the...

Composition of exhaust from a ship diesel engine using heavy fuel oil (HFO) was investigated onboard a large cargo vessel. The emitted particulate matter (PM) properties related to environmental and health impacts were investigated along with composition of the gas-phase emissions. Mass, size distribution, chemical composition and microphysical str...

There is not much data available regarding particle emissions from ships. In this study the size distributions of particles in ship exhaust from three different ships in normal operational conditions were studied using a cascade impactor. The ships were equipped with slow-or medium-speed main engines and medium-speed auxiliary engines. The fuel was...

The NOx storage and reduction performance have been investigated by means of transient flow reactor experiments for three different types of model catalysts: Pt/Ba/Al, Pt/Al and Pt/Si. The objectives of the work were to study the behavior of the catalysts when using hydrogen as a reducing agent and to investigate the influence of H2O and CO2. It wa...

Transient experiments were performed to study sulfur deactivation and regeneration of Pt/BaO/Al2O3 and Pt/SrO/Al2O3 NOx storage catalysts. It was found that the strontium-based catalysts are more easily regenerated than the barium-based catalysts and that a higher fraction of the NOx storage sites are regenerated when H2 is used in combination with...

The selective catalytic reduction of nitrogen oxides with ammonia as the reducing agent was studied using Fourier transform infrared (FTIR) spectroscopy. The adsorbed species found on a Cu-ZSM-5 powder during exposure to NO, NO2 or NH3 was compared to the adsorbed species identified during SCR conditions. A blocking effect caused by ammonia at 175...

Time-resolved FT-IR spectra of CO oxidation over Pt/Al2O3 catalysts were collected in situ in transmission mode under transient reaction conditions. Using the step-scan acquisition mode of a commercial FT-IR spectrometer, time-resolution of a few milliseconds, compared to several hundred milliseconds in the normal rapid-scan mode, could be achieved...

In this work, a kinetic model is constructed to simulate sulfur deactivation of the NOx storage performance of BaO/Al2O3 and Pt/BaO/Al2O3 catalysts. The model is based on a previous model for NOx storage under sulfur-free conditions. In the present model the storage of NOx is allowed on two storage sites, one for complete NOx uptake and one for a s...

We communicate experimental results for the oxidation of methane by oxygen over alumina supported Pd and Pt monolith catalysts under transient conditions. Temperature programmed reaction (TPReaction) and reactant pulse-response (PR) experiments have been performed, using a continuous gas-flow reactor equipped with a downstream mass spectrometer for...

Transient in situ DRIFTS and flow-reactor experiments were performed to study the storage and reduction of NOX over Pt/BaCO3/Al2O3, Pd/BaCO3/Al2O3, and Rh/BaCO3/Al2O3 samples using CO, H-2, C3H6, or C3H8 as the reducing agent. The DRIFTS results show that exposure of the examined samples to NO2 results in the formation of nitrite/nitrate peaks over...

The interaction of SO2 with Pt/BaCO3/Al2O3 NOx storage catalysts under lean and rich conditions in the absence and presence of water was investigated by means of in situ FTIR spectroscopy at 350 degrees C. For the lean condition (SO2 + O-2), surface and bulk barium sulfates were formed in addition to sulfites and surface sulfates on alumina. Pt doe...

The selective catalytic reduction of nitrogen oxides (NOx) with ammonia over ZSM-5 catalysts was studied with and without water vapor. The activity of H-, Na- and Cu-ZSM-5 was compared and the result showed that the activity was greatly enhanced by the introduction of copper ions. A comparison between Cu-ZSM-5 of different silica to alumina ratios...

The electrochemical oxygen reduction reaction on nanostructured supported platinum electrodes is measured using a newly developed solid-state polymer electrolyte electrochemical cell. Measurements were made on three types of catalytic surfaces on glassy carbon supports: nanostructured model electrodes prepared by colloidal lithography, a thin therm...

The effect of different reducing agents (H(2), CO, C(3)H(6) and C(3)H(8)) on the reduction of stored NO(x), over PM/BaO/Al(2)O(3) catalysts (PM = Pt, Pd or Rh) at 350, 250 and 150 degrees C was studied by the use of both NO(2)-TPD and transient reactor experiments. With the aim of comparing the different reducing agents and precious metals., consta...

In this investigation different experimental methods to determine the platinum dispersion of Pt/BaO/Al2O3 NOx storage catalysts are compared. The dispersion of platinum is determined independently using temperature programmed desorption of CO, dissociation of N2O, static volumetric CO and H-2 chemisorption, dynamic CO chemisorption and transmission...

Flow reactor experiments were performed to study the effect of SO2 + O2 and SO2 + H2 exposures on the NOx storage performance of Pt/BaO/Al2O3 and BaO/Al2O3 catalysts. In addition, Pt/SiO2 samples were used to study the interaction between Pt and SO2 under the two exposure conditions. For BaO/Al2O3 the two SO2 exposure conditions caused similar deac...

Modeling and flow reactor experiments are used to investigate the global kinetics for lean NOx traps (LNTs). Experiments were conducted with a Pt/Rh/BaO/Al2O3 model catalyst, and the inlet feed gas was switched between lean and rich periods. It has previously been observed that NO oxidation to NO2 is important for NOx storage, and therefore a globa...

The influence of the choice of platinum precursor on the catalytic performance of Pt/BaCO3/Al2O3 NO, storage catalysts was studied. The precursors used in the preparation of the catalysts were: (i) hexachloroplatinic acid [H2Pt(Cl)(6)], (ii) tetraammineplatinum hydroxide [Pt(NH3)(4)(OH)(2)], (iii) diammineplatinum nitrite [Pt(NH3)(2)(NO2)(2)] and (...

We review our understanding of the NO2 interaction with BaO. The presented picture has evolved from calculations using the density functional theory, reactor measurements and vibrational spectroscopy of surface species during NO2 storage on a BaO/Al2O3 catalyst and BaO powder. The DFT calculations predict nitrite formation on the BaO(1 0 0) surface...

We report experimental results for the oxidation of CO over supported Pt/Al2O3 catalysts operating in oxygen excess at atmospheric pressure. To study the reaction kinetics under transient conditions we have employed step changes of the O2 concentration by intermittently switching off the O2 supply at various temperatures ranging from 523 to 623 K....

Flow reactor experiments and X-ray photoelectron spectroscopy (XPS) measurements were used to investigate the importance of platinum oxide formation on Pt/BaO/Al2O3 NOx storage catalysts during reactions conditions. The reaction studied was NO(g) + 1/2 O2(g) ⇔ NO2(g). During NO2 exposure of the catalyst the NO2 dissociation rate decreased during th...

In this investigation, a comparative study for a NOX storage catalytic system was performed focusing on the parameters that affect the reduction by using different reductants (H2, CO, C3H6 and C3H8) and different temperatures (350, 250 and 150 °C), for a Pt/BaO/Al2O3 catalyst. Transient experiments show that H2 and CO are highly efficient reductant...

This review summarises catalyst‐based strategies and techniques for efficient control of automotive emissions with focus on methods that increase the catalytic activity at low temperatures. Technical solutions, which more indirectly improve the function of the catalyst, are briefly discussed.

Model NOx storage catalysts were used to study the sulfur deactivation of these systems using reactor studies, FTIR and XPS. It is found that the deactivation rate shows a linear dependence on the SO2 concentration and that bulk sulfates are easily formed. Experiments with SO2 present either during lean or during rich conditions show a more rapid d...

Charged NOx species (x = 1,2,3) formed upon adsorption of NO2 on BaO are characterized by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and theoretical vibrational analysis using the density functional theory (DFT). Experiments at 30 °C reveal nitrite formation. At T > 250 °C, shifts associated with formation of nitrates are o...

For NOx storage, the oxidation of NO to NO2 is an important step in the storage mechanism. In the first part of this work, model WO3/Pt/Al2O3, MoO3/Pt/Al2O3, V2O5/Pt/Al2O3, Ga2O3/Pt/Al2O3 and Pt/Al2O3 catalysts were prepared and used in flow reactor experiments. Heating ramp oxidation and steady state oxidation experiments were performed in order t...

This investigation focuses on the influence of surface acidity on the continuous catalytic reduction of NOx by propane under lean conditions. The acidity was varied by studying noble metal free alumina, silica and co-precipitated aluminium-silicates with varying alumina-silica ratio. The catalysts were characterised by isopropylamine temperature pr...

In the present work the influence of the type of noble metals present in barium oxide based NOx storage catalysts was investigated, regarding the NOx storage performance, NO oxidation, NO reduction, sulphur deactivation and sulphur regenerability. Monolith samples with combinations of platinum and rhodium, were prepared, tested in a flow-reactor, a...

In the present study, barium-based NOx, storage catalysts containing platinum, rhodium, or both noble metals were investigated. The influence of SO2 exposure conditions on the performance of NOx storage catalysts was studied using flow reactor measurements, FTIR, and XPS where the samples were exposed to lean and/or rich SO2-containing gas mixtures...

This study focuses on the influence of the support acidity on the continuous reduction of nitric oxide by hydrocarbons over supported Pt catalysts under lean conditions. The support materials used were alumina, silica and co-precipitated aluminum-silicates. Activity studies of NO reduction with either propene or propane as the reducing agent, CO ch...

Oxidation of CO over Co3O4 at ambient temperature was studied with flow reactor experiments, and in-situ spectroscopic and structural methods. The catalyst deactivates during the reaction. The rate of deactivation increased with increasing CO or CO2 gas-phase concentration but decreased with increased O2 concentration or increased temperature. Rege...

Oxidation of CO over Co3O4 at ambient temperature was studied with flow reactor experiments, and in-situ spectroscopic and structural methods. The catalyst deactivates during the reaction. The rate of deactivation increased with increasing CO or CO2 gas-phase concentration but decreased with increased O2 concentration or increased temperature. Rege...

Flow reactor experiments and XPS measurements were used to investigate the observed decrease in activity of Pt/Al2O3 and Pt/BaO/Al2O3 catalysts during reaction conditions. The reactions studied were NO(g)+1/2O2(g)⇔NO2(g). The influence of platinum dispersion on activity and on the activity decrease with time was also studied. When the Pt/Al2O3 cata...

The effect of gas composition changes on the low temperature activity for supported platinum model catalysts has been studied. By introducing well-controlled periodic O-2 pulses to a simple diluted gas mixture of CO and O-2, a substantial improvement of the low temperature oxidation activity was observed. The reason for low activity on noble metals...

The influence of SO2, H2S and COS in low concentrations on the deactivation of Pt/Rh/BaO/Al2O3 NOx storage catalysts was investigated. Different samples of the catalyst were exposed to synthetic gas mixtures mimicking lean/rich engine cycling in a mixed lean application at 400 °C. The lean gas mixture contained 8 vol.% O2, 500 vol-ppm C3H6 and 400...

A mean field model, for storage and desorption of NOx in a Pt/BaO/Al2O3 catalyst is developed using data from flow reactor experiments. This relatively complex system is divided into five smaller sub-systems and the model is divided into the following steps: (i) NO oxidation on Pt/Al2O3; (ii) NO oxidation on Pt/BaO/Al2O3; (iii) NOx storage on BaO/A...

The importance of Pt and Pd in noble metal-barium oxide type NOx storage catalysts was investigated. Model Pt/BaO/Al2O3 and Pd/BaO/Al2O3 catalysts were prepared and evaluated with respect to NOx storage capacity, activity towards NO reduction under lean conditions and NO oxidation capacity using synthetic lean burn exhausts containing NO, O2, C3H6...

NO2 adsorption at a BaO(100) surface is investigated by means of spin polarized GGA density functional theory. A periodic supercell procedure is employed, and two redox reaction channels are mapped out, involving two chemisorbed NO2 molecules per supercell. The chemisorption is studied in two subsequent steps. The reaction paths are initiated by NO...

The influence of transient changes in the gas composition on the low-temperature activity of a commercial three-way catalyst and a Pt/Al2O3 model catalyst has been studied. By introducing well-controlled periodic O2 pulses to simple gas mixtures of CO or C3H6 (in N2), a substantial improvement of the low temperature oxidation activity was observed...

The CO oxidation over Co3O4 and Co3O4/Al2O3 has been investigated using flow reactor and in situ FTIR studies. Cobalt oxide shows very high activity even at room temperature. However, a gradual deactivation takes place during reaction. The deactivated catalyst shows the presence of two different carbonate species and one graphite-like species. A po...

Total oxidation of propane with oxygen in the absence and the respective presence of SO2 in the feed gas was studied over 1 wt% Pt on gamma -Al2O3 using transient experiments with TAP (temporal analysis of products) and in situ DRIFT spectroscopy. The TAP experiments confirm the promoting role of SO2 on the conversion of propane and, moreover, show...

Modeling and flow reactor experiments were used to study the kinetics of NO, storage/release on a Pt/BaO/Al2O3 model catalyst. The mechanism for this concept can be divided into four steps: (i) NO to NO2 oxidation on Pt, (ii) NO2 storage on BaO, (iii) NO, release, and (iv) NO, reduction to N2. In this paper, we have focused on the first three steps...

We have studied the activity and stability of EBL-fabricated Pt/CeOx and Pt/SiO2 supported model catalysts during catalytic reactions. Different mixtures of H2+O2 diluted in argon and CO+O2 diluted in argon have been used in the temperature range 300–475°C. Reaction-induced morphology changes are observed for both types of samples after heat treatm...

A preparation method for making a high temperature stable monolith catalyst, using a cobalt-rich cobalt-aluminate spinel (Co1.66Al1.34O4) as the active material, is proposed. This catalyst, which is known for being active for CO oxidation at low temperatures, was prepared and characterised by BET, SEM, XRD, XPS and CO-TPD. The catalyst was tested f...

The effect of SO2 addition on the oxidation of ethyl acetate, ethanol, propane and propene, over Pt/gamma -Al2O3 and Pt/SiO2 has been investigated. The reactants (300-800 vol, ppm) were mixed with air and led through the catalyst bed. The conversions below and above light-off were recorded both in the absence and in the presence of 1-100 vol. ppm S...

The storage of NO x under lean conditions in model NO x storage catalysts as well as the deactivation by sulphur have been studied. We find that NO2 plays an important role in the storage mechanism as an oxidising agent. Two different mechanisms for this are discussed: the formation of surface peroxides and the oxidation of nitrites to nitrates. FT...

FTIR spectroscopy has been used to study samples of Al2O3, Pt/Al2O3, BaO/Al2O3 and Pt/BaO/Al2O3 under exposure to either NO2 and O2 or NO and O2, between 100 and 400°C. The resulting spectra are fitted to various species, mainly nitrites and nitrates, formed on Al2O3 and BaO. The exposure of NO2 and O2 on the Al2O3 sample results in the formation o...