Liquid Organic Hydrogen Carriers or Organic Liquid Hydrides: 40 Years of History

Abstract

The term LOHC stands for Liquid Organic Hydrogen Carriers. The term has been so well accepted by the scientific community that the studies published before the existence of this name are not very visible. In this mini-review, we have tried to rehabilitate various studies that deserve to be put back in the spotlight in the present context. Studies indeed began in the early 1980s and many publications have compared the use of various organic carriers, various catalysts and reactors. Recent reviews also include the economic aspects of this concept.

A Perspective Review on N-Heterocycles as Liquid Organic Hydrogen Carriers and Their Hydrogenation/Dehydrogenation Catalysts

“…Italian researchers later discovered the reasons for the catalysts' deactivation and attempted to combine benzene/cyclohexane and TOL/MCH. 67 In the early 2000s, analysis of the benzene/cyclohexane and TOL/MCH systems revealed their high dehydrogenation enthalpies, which necessitated dehydrogenation of cyclohexane and MCH at higher temperatures. 68 In 2006, Pez et al conducted experiments and studies which showed that doping N atoms in 9-ethylcarbazole reduced the dehydrogenation enthalpy compared to a pure carbocycle.…”

“…However, the application was restricted by the catalysts’ stability. Italian researchers later discovered the reasons for the catalysts’ deactivation and attempted to combine benzene/cyclohexane and TOL/MCH …”

A Perspective Review on N-Heterocycles as Liquid Organic Hydrogen Carriers and Their Hydrogenation/Dehydrogenation Catalysts

“…Italian researchers later discovered the reasons for the catalysts' deactivation and attempted to combine benzene/cyclohexane and TOL/MCH. 67 In the early 2000s, analysis of the benzene/cyclohexane and TOL/MCH systems revealed their high dehydrogenation enthalpies, which necessitated dehydrogenation of cyclohexane and MCH at higher temperatures. 68 In 2006, Pez et al conducted experiments and studies which showed that doping N atoms in 9-ethylcarbazole reduced the dehydrogenation enthalpy compared to a pure carbocycle.…”

“…However, the application was restricted by the catalysts’ stability. Italian researchers later discovered the reasons for the catalysts’ deactivation and attempted to combine benzene/cyclohexane and TOL/MCH …”

Future of hydrogen economy: simulation-based comparison of LOHC systems

“…A recent historical review of organic hydrogen carriers reveals that the potential of using suitable organic compounds for hydrogen storage has been studied for more than 40 years. Different groups studied several hydrogen-rich/ hydrogen-lean pairs, choosing suitable catalysts for the two steps of the circular process (Meille and Pitault 2021). In the following sections, the LOHC cycle, the applicable carriers and the catalyst are discussed before discussing the modelling methods and results.…”

Research and development of hydrogen carrier based solutions for hydrogen compression and storage

“…The loading reaction is exothermal and the unloading is endothermal, as in case of MHs, so a heat management and a heat source is necessary. During storage and transport, the LOHC can be handled at ambient conditions [49,50]. The main advantage of LOHCs is the liquid phase during hydrogen storage, which allows for transport and handling in a similar manner to other organic energy carrier (e.g.…”

A Perspective Review on N-Heterocycles as Liquid Organic Hydrogen Carriers and Their Hydrogenation/Dehydrogenation Catalysts

“…Italian researchers later discovered the reasons for the catalysts' deactivation and attempted to combine benzene/cyclohexane and TOL/MCH. 67 In the early 2000s, analysis of the benzene/cyclohexane and TOL/MCH systems revealed their high dehydrogenation enthalpies, which necessitated dehydrogenation of cyclohexane and MCH at higher temperatures. 68 In 2006, Pez et al conducted experiments and studies which showed that doping N atoms in 9-ethylcarbazole reduced the dehydrogenation enthalpy compared to a pure carbocycle.…”

“…However, the application was restricted by the catalysts’ stability. Italian researchers later discovered the reasons for the catalysts’ deactivation and attempted to combine benzene/cyclohexane and TOL/MCH …”

Future of hydrogen economy: simulation-based comparison of LOHC systems

“…A recent historical review of organic hydrogen carriers reveals that the potential of using suitable organic compounds for hydrogen storage has been studied for more than 40 years. Different groups studied several hydrogen-rich/ hydrogen-lean pairs, choosing suitable catalysts for the two steps of the circular process (Meille and Pitault 2021). In the following sections, the LOHC cycle, the applicable carriers and the catalyst are discussed before discussing the modelling methods and results.…”

Research and development of hydrogen carrier based solutions for hydrogen compression and storage

“…The loading reaction is exothermal and the unloading is endothermal, as in case of MHs, so a heat management and a heat source is necessary. During storage and transport, the LOHC can be handled at ambient conditions [49,50]. The main advantage of LOHCs is the liquid phase during hydrogen storage, which allows for transport and handling in a similar manner to other organic energy carrier (e.g.…”

A Perspective Review on N-Heterocycles as Liquid Organic Hydrogen Carriers and Their Hydrogenation/Dehydrogenation Catalysts

“…Italian researchers later discovered the reasons for the catalysts' deactivation and attempted to combine benzene/cyclohexane and TOL/MCH. 67 In the early 2000s, analysis of the benzene/cyclohexane and TOL/MCH systems revealed their high dehydrogenation enthalpies, which necessitated dehydrogenation of cyclohexane and MCH at higher temperatures. 68 In 2006, Pez et al conducted experiments and studies which showed that doping N atoms in 9-ethylcarbazole reduced the dehydrogenation enthalpy compared to a pure carbocycle.…”

“…However, the application was restricted by the catalysts’ stability. Italian researchers later discovered the reasons for the catalysts’ deactivation and attempted to combine benzene/cyclohexane and TOL/MCH …”

Future of hydrogen economy: simulation-based comparison of LOHC systems

“…A recent historical review of organic hydrogen carriers reveals that the potential of using suitable organic compounds for hydrogen storage has been studied for more than 40 years. Different groups studied several hydrogen-rich/ hydrogen-lean pairs, choosing suitable catalysts for the two steps of the circular process (Meille and Pitault 2021). In the following sections, the LOHC cycle, the applicable carriers and the catalyst are discussed before discussing the modelling methods and results.…”

Research and development of hydrogen carrier based solutions for hydrogen compression and storage

“…The loading reaction is exothermal and the unloading is endothermal, as in case of MHs, so a heat management and a heat source is necessary. During storage and transport, the LOHC can be handled at ambient conditions [49,50]. The main advantage of LOHCs is the liquid phase during hydrogen storage, which allows for transport and handling in a similar manner to other organic energy carrier (e.g.…”