Peter Wasserscheid

• Professor
• Friedrich-Alexander-University Erlangen-Nürnberg

Supported catalytically active liquid metal solutions (SCALMS) are materials composed of a liquid metal alloy deposited on a porous support. Due to the dynamic properties of the liquid metal alloy, these systems are suggested to form single atom sites, resulting in unique catalytic properties. Ga−Ni SCALMS were successfully applied to ethylene olig...

When talking about homogeneous catalyst systems, it has long been assumed that the system at hand consists of a transition metal complex in solution with the liquid interface representing the composition of the bulk solution. Now, in light of considerable developments in the study of metal complexes dissolved in ionic liquids with their negligible...

In der homogenen Katalyse geht man üblicherweise davon aus, dass sich die Konzentrationen der Übergangsmetallkomplexe an der Gas‐Flüssig‐Grenzfläche und im Volumen der Lösung nicht unterscheiden. Tatsächlich zeigen aber umfangreiche Untersuchungen an gelösten Metallkomplexen in ionischen Flüssigkeiten (Englisch: Ionic Liquids, ILs) ausgeprägte Ober...

The controlled synthesis of supported Pt nanoparticles with well‐defined sizes in the range from 1.9 to 6.0 nm and their application in the dehydrogenation of cyclic liquid organic hydrogen carrier (LOHC) molecules are demonstrated. For this purpose, a colloidal approach with a stabilized Pt precursor solution including chemical reduction with aque...

Liquid organic hydrogen carriers (LOHCs) are a promising option for hydrogen storage, but a high efficiency of the LOHC cycle is essential in order to serve as an attractive technology in the context of decarbonization. This paper presents different methods to optimize steady-state operating points of a LOHC dehydrogenation (DH) reactor. For this p...

One concept for the safe storage and transport of molecular hydrogen (H2) is the use of hydrogen carrier systems which can bind and release hydrogen in repeating cycles. In this context, the liquid system based on isopropanol and its dehydrogenated counterpart acetone is particularly interesting for applications in direct isopropanol fuel cells tha...

The release of hydrogen from liquid organic hydrogen carriers (LOHC) takes place in an endothermal dehydrogenation reaction that is accompanied by a strong volume expansion. This leads to complex hydrodynamic properties that change drastically along the reactor axis due to product gas evolution. Consequently, heat transfer into the catalytic fixed-...

The benzyltoluene- and dibenzyltoluene-based liquid organic hydrogen carrier (LOHC) technology is approaching a level of maturity that enables its large-scale implementation for hydrogen storage and transport applications. To support this progress, our study investigates the continuous dehydrogenation of both LOHC systems in a packed bed tubular re...

Despite the extensive use of 2-propanol and acetone in a wide range of applications in the chemical industry and in energy engineering, there is a lack of experimental data in the literature for their thermophysical properties including viscosity, interfacial tension, and density, especially at elevated temperatures beyond the respective normal boi...

Hydrogen storage in liquid organic hydrogen carriers (LOHC) enables the utilization of renewable energy in different sectors. In this paper, we describe the operational experience with one single LOHC system for bidirectional electrical energy storage at the kW scale. The system includes a reactor for the hydrogenation and dehydrogenation of LOHC,...

Supplementary Material to ”Operational experience with a liquid organic hydrogen carrier (LOHC) system for bidirectional storage of electrical energy over 725 hours”

In a solid catalyst with ionic liquid layer (SCILL), ionic liquid (IL) coatings are used to improve the selectivity of noble metal catalysts. To understand the origins of this selectivity control, we performed model studies by surface science methods in ultrahigh vacuum (UHV). We investigated the growth and thermal stability of ultrathin IL films b...

Supported catalytically active liquid metal solution (SCALMS) materials represent a recently developed class of heterogeneous catalysts, where the catalytic reaction takes place at the highly dynamic interface of supported liquid alloys. Ga nuggets were dispersed into nano-droplets in propan-2-ol using ultrasonication followed by the addition of Pt...

Large amounts of renewable energy will have to be stored and transported in the future. For this task, chemical hydrogen storage technologies are particularly suitable. In this paper, we show that the DME/CO2 storage cycle is especially promising for point-to-point transport of renewable hydrogen over long distances. Surprisingly, this technology h...

This contribution demonstrates the application of light scattering and related optical techniques for the characterization of fluids relevant for hydrogen (H2) storage and transport, with emphasis on the accurate determination of thermophysical properties. Conventional dynamic light scattering (DLS), surface light scattering (SLS), and the shadowgr...

Fluorene (H0-F) and perhydrofluorene (H12-F) represent process-related byproducts formed by a dehydrocyclization step in the liquid organic hydrogen carrier (LOHC) system based on diphenylmethane (H0-DPM) and dicyclohexylmethane (H12-DPM). The influence of these byproducts on the liquid viscosity, surface tension, and liquid density of the DPM-base...

Hydrogen (H2) is considered a game changer in the global energy transition. It can be produced on a large scale via water electrolysis using renewable wind or solar power and has a wide range of potential applications in all important fields of energy supply. The gravimetric storage density of H2 with a lower heating value (LHV) of 33.3 kWh/kg is e...

The benzyltoluene‐based liquid organic hydrogen carrier (LOHC) system enables the safe transport and loss‐free storage of hydrogen. At least 26% of the lower heating value of the released hydrogen, however, have to be invested in form of heat to release the stored hydrogen. The low operation temperatures of catalytic distillation (CD) can facilitat...

Homocyclic aromatics with different degrees of alkylation have been investigated so far as Liquid Organic Hydrogen Carriers (LOHC). A low enthalpy of reaction for the dehydrogenation reaction is generally considered beneficial. Values available for crowded, multi-alkylated aromatics, such as hexamethyl benzene, indicate that these substances could...

Alkyl-cyclohexanes can be considered as suitable model compounds to understand the thermochemistry of aromatic compounds and their hydrogenated counterparts discussed as Liquid Organic Hydrogen Carrier systems. Thermochemical measurements on these hydrogen-rich compounds are thwarted by complications due to the 99.9 % purity limitation and sample s...

Indole has been proposed as a Liquid Organic Hydrogen Carrier (LOHC) component. Its hydrogenation leads to octahydro indole, which can subsequently release hydrogen again in an endothermic, catalytic dehydrogenation reaction. This reaction requires high temperatures due to limitations by the reaction equilibrium. It is therefore interesting to find...

Temperature control in heat exchangers in reacting and non-reacting flows is of great importance for process optimization. In this context, phosphor thermometry is a promising technique for remote planar temperature sensing. The thermometry technique is based on exciting a luminescent material by a laser pulse and analysing the subsequent phosphore...

The observable reaction rate of heterogeneously catalyzed reactions is known to be limited either by the intrinsic kinetics of the catalytic transformation or by the rate of pore and/or film diffusion. Here, we show that in gas generation reactions from liquid reactants, the nucleation of gas bubbles in the catalyst pore structure represents an add...

We studied the formation and surface behavior of Pt(II) and Pd(II) complexes with ligand systems derived from two nitrile‐functionalized ionic liquids (ILs) in solution using angle‐resolved X‐ray photoelectron spectroscopy (ARXPS). These ligand systems enabled a high solubility of the metal complexes in IL solution. The complexes were prepared by s...

In hydrogenation and dehydrogenation processes of liquid organic hydrogen carriers (LOHCs), molecular hydrogen (H2) is present, but its influence on the thermophysical properties of the LOHC compounds is still hardly known. This study provides experimental results from surface light scattering and predictions from molecular dynamics simulations on...

Liquid organic hydrogen carrier (LOHC) systems offer a promising way to store and transport hydrogen in a safe and dense form at ambient conditions. Compared to other chemical hydrogen storage systems such as ammonia, formic acid, and methanol, LOHC systems enable reversible storage of hydrogen. For the endothermic hydrogen release reaction, heat a...

Liquid Organic Hydrogen Carriers are substances that store hydrogen by reversible hydrogenation of aromatic compounds. A major advantage is the fact that they enable the safe and dense storage of large amounts of hydrogen. Nitrogen-containing heterocycles, particularly with five-membered rings, have demonstrated the advantage of lower heats of reac...

This work shows the effect of selected ionic liquids on the catalytic performance of a Cu/Al2O3 catalyst towards citral hydrogenation. The Cu/Al2O3 was prepared using a combination of wet impregnation and strong electrostatic interaction technique. The catalyst was coated with three ionic liquids, namely: [C4C1Pyrr][OTf], [C2C1C1Im][NTf2], and [C2C...

In the present study, the liquid viscosity and surface tension of fluorene (H0-F) and its fully hydrogenated counterpart perhydrofluorene (H12-F), representing process-relevant by-products of the liquid organic hydrogen carrier (LOHC) system based on diphenylmethane and dicyclohexylmethane and potentially interesting LOHC compounds by themselves, w...

Molecular solar thermal (MOST) systems combine solar energy conversion, storage, and release in simple one‐photon one‐molecule processes. Here, we address the electrochemically triggered energy release from an azothiophene‐based MOST system by photoelectrochemical infrared reflection absorption spectroscopy (PEC‐IRRAS) and density functional theory...

Adding to the versatile class of ionic liquids, we report a new series of hydrophilic polyethylene glycol-functionalized room-temperature ionic liquids, offering interesting thermo- and electrochemical behavior as well as remarkable surface properties. A scalable and generally applicable synthetic procedure for the preparation of N,N’-bis(polyethyl...

In this study we present Mn as a possible candidate for modification of Pt/Al2O3 catalysts. We establish the pair of dicyclohexylmethane/diphenylmethane (Hx-DPM) as a model LOHC system. It allows for a better understanding of side product formation during dehydrogenation of other commonly used LOHC pairs such as perhydro-dibenzyltoluene/dibenzyltol...

Isolated active sites have great potential to be highly efficient and stable in heterogeneous catalysis, while enabling low costs due to the low transition metal content. Herein, we present results on the synthesis, first catalytic trials, and characterization of the Ga 9 Rh 2 phase and the hitherto not-studied Ga 3 Rh phase. We used XRD and TEM fo...

2‐Propanol/acetone is a promising LOHC (Liquid Organic Hydrogen Carrier) system for fuel cell reactions. In this paper six different concepts for a 2‐propanol/acetone fuel cell system are evaluated in a Matlab simulation with respect to their thermodynamic integration and technical feasibility. Four of the concepts use a direct 2‐propanol fuel cell...

The “solid catalyst with ionic liquid layer” (SCILL) is an extremely successful new concept in heterogeneous catalysis. The idea is to boost the selectivity of a catalyst by its modification with an ionic liquid (IL). Here, we show that it is possible to use the same concept in electrocatalysis for the selective transformation of organic compounds....

Liquid organic hydrogen carriers (LOHCs) relying on eutectic diphenylmethane-biphenyl mixtures feature advantageous characteristics such as low melting points and large hydrogen storage capacities. For contributing to a reliable database of process-relevant thermophysical properties, the present study investigates the viscosity, surface tension, an...

The ‘solid catalyst with ionic liquid layer’ (SCILL) is an extremely successful new concept in heterogeneous catalysis. The idea is to boost the selectivity of a catalyst by its modification with an ionic liquid (IL). Here, we show that it is possible to use the same concept in electrocatalysis for the selective transformation of organic compounds....

The storage of hydrogen in liquid organic hydrogen carriers (LOHCs) represents a safe and easy to handle storage solution for energy from renewable sources. Dibenzyltoluene (H0-DBT)/perhydro-dibenzyltoluene (H18-DBT) is a promising LOHC system due to its low flammability, wide liquid range and high storage density for hydrogen. However, this LOHC s...

Adding to the versatile class of ionic liquids, we report the detailed structure and property analysis of a new class of asymmetrically substituted imidazolium salts, offering interesting thermal characteristics, such as liquid crystalline behavior, polymorphism or glass transitions. A scalable general synthetic procedure for N‐polyaryl‐N’‐alkyl‐fu...

The liquid organic hydrogen carrier (LOHC) diphenylmethane may react to benzophenone in the presence of air, especially at elevated temperatures. Therefore, information about the influence of benzophenone added to diphenylmethane on process-relevant thermophysical properties is required. In the present contribution, the liquid viscosity, surface te...

Task‐specific polyaryl‐/oligoether‐substituted, imidazolium‐based ionic liquids (ILs) with linker moieties enable interaction with electrochemically active surfaces. Thus, electron and proton transfer ought to be facilitated along the side chains. When used as a precursor for carbene ligands, the complex's reactivity and potential catalytic activit...

During the processes of hydrogenation or dehydrogenation of liquid organic hydrogen carriers (LOHCs), knowledge of the current degree of hydrogenation (DoH) is often essential. The present study shows that depolarized Raman spectroscopy allows the accurate determination of the DoH of the model LOHC system diphenylmethane (H0-DPM)/dicyclohexylmethan...

LOHC technologies enable safe and efficient hydrogen logistics using the existent fuel infrastructure. This study presents benzyltoluene (H0 BT)/ perhydro benzyltoluene (H12 BT) as a highly attractive technical LOHC system....

Ionic and covalent cross-linking of an acid–base blend is used to manufacture membranes with high stability against dissolution and reduced isopropanol and acetone crossover for direct-isopropanol fuel cell applications.

For the efficient design of hydrogenation and dehydrogenation processes, a comprehensive database for the viscosity, surface tension, and density of mixtures of the diphenylmethane-based liquid organic hydrogen carrier system and the pure intermediate cyclohexylphenylmethane measured by complementary optical and conventional methods and calculated...

Non-precious metal supported catalytically active liquid metal solutions exhibit attractive performance in ethylene oligomerization.

Supported catalytically active liquid metal solutions (SCALMS) of Pt in Ga (2 at.-% Pt) were studied in the temperature range of 500 to 600 °C for propane dehydrogenation. A facile synthesis procedure using ultrasonication was implemented and compared to a previously reported organo-chemical route for gallium deposition. The procedure was applied t...

In solid catalysts with ionic liquid layers (SCILLs), ionic liquid (IL) thin films are used to modify the activity and selectivity of catalytic materials. In this work, we investigated the adsorption behavior of the IL 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [C2C1Im][NTf2] on Pt(111) by combining experimental and theoretical...

We used temperature-programmed infrared reflection absorption spectroscopy (TP-IRAS) to study the desorption behavior of CO on Pt(111) coadsorbed with four kinds of ionic liquids (ILs), namely 1-butyl-1-methyl-pyrrolidinium-bis(trifluoromethylsulfonyl)imide ([C4C1Pyr][NTf2]), 1-ethyl-3-methyl-imidazolium-bis(trifluoromethylsulfonyl)imide ([C2C1Im][...

Hydrogen storage in liquid organic hydrogen carriers (LOHC) such as the substance system dibenzyltoluene/perhydro-dibenzyltoluene (H0/H18-DBT) offers a promising alternative to conventional methods. In this contribution, we describe the successful demonstration of the dynamic combined operation of a continuously operated LOHC reactor and a PEM (pol...

Supplementary Material to ”Combined dynamic operation of PEM fuel cell and continuous dehydrogenation of perhydro-dibenzyltoluene”

The pyrolytic treatment of the novel ionic liquid 1-ethyl-3-methyl-imidazolium tetrakis-(1-imidazolyl)borate ([EMIM][BIm4]) allowed the preparation of B/N-doped carbonaceous materials with an exceptional performance in the adsorptive removal of the cationic dye methylene blue (MB) from wastewater. [EMIM][BIm4] was prepared via an easy and scalable...

Liquid Organic Hydrogen Carriers (LOHC) offer a promising solution for hydrogen storage in the existing infrastructure for conventional fuels. Within this framework, the isopropanol/acetone couple as a light-LOHC system is used to generate electricity in a direct isopropanol fuel cell (DIFC). This work focuses on the impact of catalyst loading, ion...

Liquid organic hydrogen carrier (LOHC) systems store hydrogen through a catalyst-promoted exothermal hydrogenation reaction and release hydrogen through an endothermal catalytic dehydrogenation reaction. At a given pressure and temperature the amount of releasable hydrogen depends on the reaction equilibrium of the hydrogenation/dehydrogenation rea...

Hydrogen storage and transport via Liquid Organic Hydrogen Carriers (LOHC) is gaining increasing attention. In this study, we present catalytically activated stainless steel plates as a promising alternative to the commonly used pellet catalysts for the dehydrogenation of perhydro dibenzyltoluene (H18-DBT). These plate catalysts promise better heat...

The present study demonstrates a novel method for the NOx reduction by H2 in lean exhaust gases using H2 released from a Liquid Organic Hydrogen Carrier (LOHC). The concept implies the simultaneous H2 production and H2-deNOx reaction, which both take place on the same catalyst. In a first approach, the catalyst was suspended in the LOHC, while the...

The 2-propanol fuel cell has been shown to hold several key advantages over the more established methanol fuel cell, including a comparably high real open circuit voltage, reduced fuel crossover through a Nafion membrane and a benign toxicological fuel profile. Additionally, while the highly-selective partial oxidation of 2-propanol to acetone in a...

We present a comprehensive structural and analytical characterization of the highly promising supported catalytically active liquid metal solutions (SCALMS) system. This novel catalyst shows excellent performance for alkane dehydrogenation, especially in terms of resistance to coking. SCALMS consists of a porous support containing catalytically act...

The invention relates to a continuous flow reactor (1) having a wall (10) which delimits a channel (15), wherein at least one sub-area (105) is arranged in the channel that has micro-structuring (2) which includes individual structures, the diameter of which on a base is between about 10 µm to about 100 µm. The invention further relates to methods...

In the present study, physico-chemical properties of the liquid organic hydrogen carrier (LOHC) system diphenylmethane/dicyclohexylmethane in the presence of dissolved hydrogen are presented for temperatures up to 523 K and pressures up to 10 MPa. Solubility of hydrogen, interfacial tension, and liquid density were measured by the isochoric saturat...

Liquid organic hydrogen carrier (LOHC) systems represent a promising storage option for hydrogen produced from renewable electricity by water electrolysis. Regarding the efficiency of the endothermal hydrogen release reaction, this technology greatly benefits from a direct heat integration with the waste heat of the energetic use of the released hy...

Bei der stofflichen Speicherung von elementarem Wasserstoff an flüssigen organischen Trägermolekülen ist die endotherme Wiederfreisetzung die größte Herausforderung. Die stabile chemische Bindung des Wasserstoffes an sogenannten Liquid Organic Hydrogen Carriers (LOHCs) ermöglicht den gefahrlosen Transport und die dauerhafte Einlagerung von Energie....

Lubricant-infused repellent coatings provide efficient repellency against contamination as the lubricant avoids direct contact between the surface and any contaminant to be repelled. Here, we address two mechanisms that potentially cause failure of the coating by loss of the liquid lubricant, and present a strategy for long-lasting coatings. We use...

We demonstrate that the combination of hydrogen release from a Liquid Organic Hydrogen Carrier (LOHC) system with electrochemical hydrogen compression (EHC) provides three decisive advantages over the state-of-the-art hydrogen provision from such storage system: a) The EHC device produces reduced hydrogen pressure on its suction side connected to t...

This review deals with the chemical storage of green hydrogen in form of Liquid Organic Hydrogen Carrier (LOHC) systems. LOHC systems store hydrogen by an exothermal catalytic hydrogenation reaction that converts the hydrogen-lean compounds of the LOHC system to their hydrogen-rich counterparts. All compounds of a technically suitable LOHC system a...

The kinetics of the acid catalyzed reactions of acetaldehyde ammonia trimer (AAT) and paraldehyde (para) to 2-methyl-5-ethyl pyridine (MEP) in the presence of an acid catalyst were investigated systematically. A...

Formic acid decomposition (FAD) generates H 2 at low temperatures. However, many known catalyst systems suffer from deactivation due to competing side reactions during FAD. In this work, we focus on...

The two ionic compounds [Ph4P][NTf2] and Cs[NTf2] were qualified to be suitable liquid materials for different high temperature applications. Development and optimization of these application techniques require knowledge of the thermodynamic properties of vaporization. Vapor pressures and vaporization enthalpies have been measured by using quartz‐c...

In this study, the thermal conductivity of diphenylmethane, benzyltoluene, and dibenzyltoluene and their fully hydrogenated counterparts relevant in the context of the liquid organic hydrogen carrier (LOHC) technology was investigated. For the determination of the thermal conductivity between 298.15 and 323.15 K at atmospheric pressure with an expa...

Low‐temperature synthesis in ionic liquids (ILs) offers an efficient route for the preparation of metal oxide nanomaterials with tailor‐made properties in a water‐free environment. In this work, we investigated the role of 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [C4C1Pyr][NTf2] in the synthesis of cobalt oxide nanoparticles...

The need to supply significant amounts of heat at the high temperature level required thermodynamically for cycloalkane dehydrogenation has so far been seen as the main hurdle to bring the otherwise highly attractive Liquid Organic Hydrogen Carrier (LOHC) technology to broad technical use. The LOHC technology promises infrastructure-compatible stor...

Liquid Organic Hydrogen Carrier (LOHC) systems represent a promising option for hydrogen storage and transport in chemically bound and infrastructure-compatible form. For multiple use of the carrier liquid in repetitive hydrogenation/dehydrogenation cycles, the applied dehydrogenation catalyst has to provide a combination of high productivity and e...

In this study, the performance of an In2O3/ZrO2 catalyst for hydrogenation of CO2 to methanol is reported in presence of typical impurities of industrial CO2 feed gas streams. Experiments were performed with defined amounts of SO2, H2S, NO2, NH3 and hydrocarbons purposely added to the reaction mixture under industrially relevant conditions (225-275...

Mixtures of fluorinated and non-fluorinated ionic liquids (ILs) show a distinct structural organization in the bulk and at the surface. To understand how such microscopic effects influence the macroscopic bulk and surface properties of IL mixtures, knowledge of corresponding thermophysical properties including viscosity and surface tension is requi...

The use of gallium‐rich, Supported Catalytically Active Liquid Metal Solution (SCALMS) is a promising new concept to achieve catalysis with atomically dispersed active metal atoms. Expanding our previous work on short alkane dehydrogenation, we present here the application of SCALMS for the dehydrogenation of methylcyclohexane (MCH) to toluene (TOL...