Electrocatalysts for the generation of hydrogen, oxygen and synthesis gas

Sapountzi, F.M.; Gracia, José; Weststrate, C.J.; Fredriksson, Hans; Niemantsverdriet, J.W.

doi:10.1016/j.pecs.2016.09.001

Cited by 608 publications

(335 citation statements)

References 408 publications

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“…An ideal electrocatalyst would exhibit selectivity toward hydrogenation over hydrogen evolution, high conductivity, and stability at extreme pH values and high overpotentials . Currently, the most commonly studied electrocatalysts are noble metals loaded onto carbon (e. g., Pd/C or Pt/C) aimed at improving stability compared to either material separately . To combat stability limitations and expand the range of potential electrocatalysts, we investigated a hybrid cathode that is a physical mixture of an electrocatalyst and a metal loaded onto a conventional metal oxide support (in this case alumina, Al 2 O 3 ), in a proton exchange membrane (PEM) reactor.…”

Section: Introductionmentioning

confidence: 99%

Selective Hydrogenation of Furfural in a Proton Exchange Membrane Reactor Using Hybrid Pd/Pd Black on Alumina

et al. 2019

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Conventional thermocatalytic hydrogenation employs high temperatures and pressures and often exhibits low selectivity toward desired products. Electrochemical hydrogenation can reduce energy input by operating at ambient conditions and improving process control and selectivity; however, electrocatalysts face stability and conductivity limitations. To overcome these obstacles, we physically mixed a traditional electrocatalyst (Pd black) with a hydrogenation‐active metal (Pd) supported on a conventional metal oxide support (alumina, Al2O3) and investigated electrochemical hydrogenation of furfural, a model biomass compound. Experiments were conducted in a proton exchange membrane (PEM) reactor, in which synthesized electrocatalysts were used as cathodes. Catalysts with Pd black and varying loadings of Pd on Al2O3 were used to determine the impact of hydrogen spillover on electrocatalytic hydrogenation mechanisms, selectivity, and rates. Observed hydrogenation rates and selectivities were linked to structural and compositional properties of the catalyst mixtures. Of the Pd black cathodes tested, 5 wt % Pd/Al2O3 exhibited production rates as high as pure Pd black and higher selectivity towards completely hydrogenated products. Improved selectivity and rates were attributed to a synergistic interaction between Pd black and 5 wt % Pd/Al2O3 in which Pd/Al2O3 increased the number of active sites, while Pd black provided stable conductivity.

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Section: Introductionmentioning

confidence: 99%

Selective Hydrogenation of Furfural in a Proton Exchange Membrane Reactor Using Hybrid Pd/Pd Black on Alumina

et al. 2019

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“…Since at room temperature, the electrolysis process is performed very slow (approximately 10 −7 mol/L), an electrolyte is dissolved in water to improve water conductivity and ameliorate electrolysis process. Electrolysis technology is classified to three categories based on the employed electrolyte (Figure ), which can be considered as the near‐term large‐scale hydrogen production technologies: liquid electrolyte (alkaline water electrolysis [AWE]); solid oxide electrolyte (high‐temperature electrolysis); and electrolysis in acid ionomer environment (polymer electrolyte membrane [PEM] electrolysis/solid polymer electrolysis) …”

Section: Concentrated Solar Thermal Hydrogen Productionmentioning

confidence: 99%

“…Oxygen evolution takes place at the anode; hydrogen evolves at the cathode. In solid oxide electrolysis, an O 2− ‐conducting electrolyte, with a nickel/yttria‐stabilized zirconia cathode and a lanthanum strontium manganite (LSM) anode [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Concentrated Solar Thermal Hydrogen Productionmentioning

confidence: 99%

Hydrogen from solar energy, a clean energy carrier from a sustainable source of energy

2020

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Summary Solar energy is going to play a crucial role in the future energy scenario of the world that conducts interests to solar‐to‐hydrogen as a means of achieving a clean energy carrier. Hydrogen is a sustainable energy carrier, capable of substituting fossil fuels and decreasing carbon dioxide (CO2) emission to save the world from global warming. Hydrogen production from ubiquitous sustainable solar energy and an abundantly available water is an environmentally friendly solution for globally increasing energy demands and ensures long‐term energy security. Among various solar hydrogen production routes, this study concentrates on solar thermolysis, solar thermal hydrogen via electrolysis, thermochemical water splitting, fossil fuels decarbonization, and photovoltaic‐based hydrogen production with special focus on the concentrated photovoltaic (CPV) system. Energy management and thermodynamic analysis of CPV‐based hydrogen production as the near‐term sustainable option are developed. The capability of three electrolysis systems including alkaline water electrolysis (AWE), polymer electrolyte membrane electrolysis, and solid oxide electrolysis for coupling to solar systems for H2 production is discussed. Since the cost of solar hydrogen has a very large range because of the various employed technologies, the challenges, pros and cons of the different methods, and the commercialization processes are also noticed. Among three electrolysis technologies considered for postulated solar hydrogen economy, AWE is found the most mature to integrate with the CPV system. Although substantial progresses have been made in solar hydrogen production technologies, the review indicates that these systems require further maturation to emulate the produced grid‐based hydrogen.

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“…The reference case is for water electrolysis and the production of hydrogen only. The operation temperature was chosen based on experimental data (Laguna-Bercero, 2012; Momma et al, 1997;Sapountzi et al, 2017) and was pushed to values above the typically used 1273 K (all the way up to 1500 K), in order to explore high temperature benefits potentially guide future electrolyzer development. The current density range was chosen based on experimental data (Fang et al, 2015;Knibbe et al, 2010;Zhan et al, 2009).…”

Section: Reference Case Comparison Of the Three Systemsmentioning

confidence: 99%

Techno-economic modeling and optimization of solar-driven high-temperature electrolysis systems

Lin

Haussener

2017

Solar Energy

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a b s t r a c tWe present a techno-economic analysis of solar-driven high-temperature electrolysis systems used for the production of hydrogen and synthesis gas. We consider different strategies for the incorporation of solar energy, distinguished by the use of differing technologies to provide solar power and heat: (i) thermal approaches (system 1) using concentrated solar technologies to provide heat and to generate electricity through thermodynamic cycles, (ii) electrical approaches (system 2) using photovoltaic technologies to provide electricity and to generate heat through electrical heaters, and (iii) hybrid approaches (system 3) utilizing concentrated solar technologies and photovoltaics to provide heat and electricity, respectively. We find that system 3 generates hydrogen at a high efficiency (g STF = 9.9%, slightly lower than the best performing system 1 with 10.6%) and at a low cost (C fuel = $4.9/kg, lowest cost of all three systems) at reference conditions, providing evidence for the competitiveness of this hybrid approach for scaled solar hydrogen generation. Sensitivity analysis indicates an optimal working temperature for system 3 of 1350 K, which balances the increased thermal receiver losses with the reduced electrolysis cell potential when increasing the temperature. Lower working pressure always favors high system efficiency and low cost. The working current densities for thermoneutral voltage were determined for various temperature and pressure combinations, and trends for efficient and cost-effective thermoneutral operation were identified. The water conversion extent was optimized to avoid mass transport limitations in the electrodes while ensuring large fuel generation rates. For synthesis gas production, a H 2 /CO molar ratio of 2 can be achieved by tuning the inlet feeding molar ratio of CO 2 / H 2 O, temperature, and pressure. This study introduces a flexible simulation framework of solar-driven high-temperature electrolysis systems allowing for the assessment of competing solar integration approaches and for the guidance of the operational conditions maximizing efficiency and minimizing cost, providing pathways for scalable solar fuel processing.

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Electrocatalysts for the generation of hydrogen, oxygen and synthesis gas

Cited by 608 publications

References 408 publications

Selective Hydrogenation of Furfural in a Proton Exchange Membrane Reactor Using Hybrid Pd/Pd Black on Alumina

Selective Hydrogenation of Furfural in a Proton Exchange Membrane Reactor Using Hybrid Pd/Pd Black on Alumina

Hydrogen from solar energy, a clean energy carrier from a sustainable source of energy

Techno-economic modeling and optimization of solar-driven high-temperature electrolysis systems

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