Hydrogen Production Technologies Research Articles

Avogadro Colloquia in Rome on “Vision and Opportunities of a Sustainable Hydrogen Society”

Abstract The fifth edition of Avogadro Colloquia entitled “From Water to Chemicals: Vision and Opportunities of a Sustainable Hydrogen Society”, jointly organized by the Department of Chemical Sciences and Materials Technologies of the National Research Council (DSCTM CNR) and the Italian Chemical Society (SCI), was held at the CNR headquarters in Rome on December 15th–16th, 2022. This relevant periodic conference of SCI also was the first event for the celebrations of the Centenary of the Italian CNR. This edition of the Colloquia was focused on the technologies for hydrogen production and use in the so-called green transition towards a society with reduced CO2 emissions. Such technologies well fit the objectives recommended by the United Nations and by Mission EU2030 for the mitigation of the climate change. Greeting addresses to this event were given by the CNR president Maria Chiara Carrozza, the president of SCI Gaetano Guerra, the elected president of the European Chemical Society (EuChemS) Angela Agostiano, the IUPAC president Javier García Martínez and the director of DSCTM CNR Lidia Armelao. All the representatives of the national and international chemical societies underlined the key role of chemical sciences and innovative materials in the green transition.

Innovations in Photocatalytic and Photoelectrocatalytic Water Splitting: Pathways to Efficiently Convert Biomass into Renewable Energy and Chemicals

AbstractThis review comprehensively explores the integration of photocatalytic (PC) and photoelectrocatalytic (PEC) technologies for hydrogen production via water splitting, in synergy with the efficient conversion of biomass resources. This synergistic strategy significantly boosts hydrogen production rates in both PC and PEC systems and enhances solar energy conversion efficiency. Furthermore, it enables selective conversion of cost‐effective biomass via precise modulation of catalyst structures, paving a novel pathway for green hydrogen generation and synthesis of high‐value chemicals. Specifically, the manuscript highlights recent progress in the oxidation and coupling reactions of biomass derivatives, such as methanol, ethanol, glycerol, and 5‐hydroxymethylfurfural, in PC/PEC systems. It reveals their potential to enhance hydrogen production efficiency and the synthesis of high‐value organic compounds. Future research should focus on employing in‐situ characterization techniques and theoretical simulations to deeply understand reaction mechanisms, thus advancing the field of biomass conversion through photocatalytic/photoelectrocatalytic methods.

Analyzing the hydrogen energy development policies of leading countries

Subject. The article investigates the development of hydrogen production technologies and use of renewable energy sources. Objectives. The focus is on assessing prospects for hydrogen energy development in the USA, Russia, China, and Germany. Methods. The study employed methods of comparative analysis. Results. We established that the development of hydrogen energy promotes carbon neutrality and the shaping of energy structure of the future. Conclusions. The cost of hydrogen production remains the main problem that hinders the widespread use of hydrogen energy.

Industry R&D needs in hydrogen safety

Hydrogen's unique physicochemical and combustion properties make it stand out among fuels as new hydrogen production technologies, means of transportation, and consumers emerge. The future viability of these technological solutions will depend on numerous factors, including safety, environmental, regulatory, and economic considerations. Safe deployment of these technologies requires additional research and development activities. These range from an improved quantitative understanding of hydrogen leaks, material limitations due to embrittlement, very large-volume liquefied hydrogen storage and transport, to equipment- and usage-specific considerations as is the case for gas turbines and electrolyzers.

Sulfite permeability and sulfur accumulation in a sulfite depolarized electrolyser

Sulfur dioxide or sulfite depolarized electrolyser is considered a promising technology for green hydrogen production. A sulfite depolarized electrolyser adopting sulfite wastewater is developed for both hydrogen production and wastewater treatment in our project, e.g. flue gas desulfurization wastewater and lead plate pre-desulfurization solution. Sulfite permeability and sulfur accumulation are primary challenges of the sulfite depolarized electrolyser for long-term stability. The electrochemical behaviors of SO32− reduction are investigated particularly here, which exhibits a 3.06-electron route on the homemade Pt-Pd/C catalyst. The reduction of SO32− to S0 is observed using an electrochemical quartz crystal microbalance. The sulfite diffusion coefficients of three proton exchange membranes are also determined. A frequent polarity inverted electrolysis is developed to remove the sulfur deposits and keep cell stability. Adopting a lead plate pre-desulfurization solution as the anolyte, both the fresh and repaired sulfite depolarized electrolyser can achieve a remarkable current density of > 500 mA/cm2 at 2.0 V. 200 h long-term test indicates excellent anodic depolarization and long-term stability for hydrogen production. The strategy may shed light on the further development of industrial applications.

Roadmap for Greening the Economy of Turkmenistan

Over the past decades, interest in renewable energy has grown, this is due to the aggravation of climate change. The emerging trend of decarbonization of the world economy, including transport and energy, which are one of the main sources of air pollution with carbon dioxide emissions. The article discusses issues of climate change, decarbonization scenario, a road map for “greening” the economy, and presents a brief analysis of trends in the development of hydrogen energy and the importance of the development of “green” hydrogen in the world and in Turkmenistan. The main attention is paid to the prospects and scale of development of hydrogen energy to a certain extent will depend on the characteristics of the hydrogen sources proposed for use ­, primary energy sources and hydrogen production technologies, environmental consequences when using different approaches to hydrogen production, expected costs for hydrogen production, potential consumers and volumes of hydrogen consumption within the country and abroad, technologies for storing and delivering hydrogen to consumers, the competitiveness of hydrogen as an energy carrier in the domestic and foreign markets, taking into account all the necessary costs and a potential “transboundary carbon ­tax”.

A comprehensive study of parameters distribution in a short PEM water electrolyzer stack utilizing a full-scale multi-physics model

Proton exchange membrane (PEM) electrolyzer is regarded as one of the most promising technologies for hydrogen production. To meet the requirements of large-scale hydrogen production, PEM electrolyzer stack that composed by series units are necessary. However, the composition brings extra problems such as maldistribution from the manifold to each unit, which results in parameters differences among the units and further gives rise to stack degradation. In this study, a full-scale three-dimensional multi-physics model is developed to simulate a short PEM electrolyzer stack with four single electrolyzer units. All the electrolyzer components and connections (e.g. manifold) are included in the model, and the temperature distribution, liquid saturation, membrane water content and electrolyzer performance are investigated in detail. The results indicate that performance of each single electrolyzer decreases from the first to the last unit along the water flow direction. It is recommended that the inlet temperature of electrolyzer stack should not exceed 60°C. To ease the thermal management, the water supply mode for cathode side can obviously lower the stack temperature to a preferred range, and improve the temperature uniformity. This study provides a comprehensive understanding of the distribution behaviors inside the electrolyzer stack and guides the operating parameters optimization.

Evaluation of sustainable hydrogen production technologies on an industrial scale using comparative analysis of decision-making methods.

Due to its various advantages in different industrial fields, hydrogen can provide energy based on sustainability goals and recreates a critical function in the economy of countries. In this regard, evaluating hydrogen production technologies on an industrial scale is necessary for industrial development and economic growth. Therefore, this study proposes a comprehensive, integrated framework of hybrid fuzzy decision-making for assessing hydrogen production technologies in Iran. In addition to considering sustainability factors, political, technical, and reliability indicators are also assessed in this research to make a comprehensive assessment. The Fuzzy Step-wise Weight Assessment Ratio Analysis (F-SWARA) technique determines the importance of indicators, and the Fuzzy Weighted Aggregates Sum-Product Assessment (F-WASPAS) approach ranks technologies. The weighing findings indicated that the sub-indices of investment cost, technical infrastructure development, and implementation costs were introduced as the most significant sub-indices with weights of 0.226, 0.151, and 0.126, respectively. The evaluation findings with the F-WASPAS method and comparative analysis with various decision-making methods revealed that electrolysis based on solar energy and electrolysis based on wind energy technologies had the highest preference. In this regard, the infrastructure and costs of hydrogen production can be improved by presenting various incentives, such as improving financial conditions while attracting investment and increasing cooperation with top companies. So, sustainable development, economic growth, and industrial development are provided.

A novel method for hydrogen synthesis in natural gas reservoirs

Hydrogen has been proven as a promising energy resource for a clean and sustainable future. However, the complete replacement of conventional hydrocarbon energy sources poses a challenge due to their widespread industrial utilization. Despite the gradual depletion of petroleum and natural gas reserves, they continued to serve as primary energy sources for many decades. But what if we could repurpose these hydrocarbons? Currently, fossil fuels that are both non-renewable and environmentally unfriendly are directly used for energy generation. Instead, we could convert hydrocarbons into a significantly cleaner alternative – hydrogen. This process implies in situ hydrogen generation even before hydrocarbons are recovered from a reservoir without releasing greenhouse gases into the atmosphere. In this context, we explore the conversion of methane into hydrogen in the gas reservoir with zero oil saturation via steam methane reforming initiated by in situ gas combustion. In the experimental model, different rock porous media were utilized and the process parameters such as temperature and the steam-to-methane ratio were varied. The outcome reveals a range of variations, each yielding different concentrations of hydrogen produced depending on these adjustable parameters. Our findings suggest the incredible potential for underground hydrogen generation in natural gas reservoirs. This approach holds great promise as a leading candidate for the foreseeable future, benefiting from the synergy of the fossil fuel industry and an innovative hydrogen production technology.

Ultra-High Performance of In Situ Constructed Trimetallic (Pd, Fe, Co) Nanoparticles on Carbon Paper as an Electrocatalyst for Large Current Density Oxygen Evolution Reaction in Alkaline Seawater

Seawater electrocatalysis holds significant promise as a technology for hydrogen production. A simple and low-cost impregnation-hydrothermal and thermal reduction strategy was used to synthesize in situ constructed three-dimensional porous trimetallic (Pd, Fe, and Co) anchored on a cheap and high-conducting carbon paper (CP) electrode for water electrolysis in alkaline media. The fabricated PdFeCo1−xONPs@CP electrode had super-hydrophilic and superaerophobic properties, allowing for the efficient removal of oxygen bubbles from the electrode surface due to the close interaction between the electrode and electrolyte. Furthermore, the synergistic effect of trimetallics and CP-fibers significantly increased OER intrinsic activity. PdFeCo1−xONPs@CP catalyst demonstrated critical low overpotentials of 220 and 300 mV, resulting in an extraordinarily high current density of 100 mA cm−2. For the full cell overall water splitting performance, cell overpotentials as low as 140 and 151 mV were needed to drive 10 mA cm−2 in seawater and alkaline solution electrolytes.

Crystalline-dependent surface reconstruction at low applied potential region for enhanced oxygen evolution reaction

Alkaline water electrolysis is apreferred technology for large-scale green hydrogen production. For most active transition metal-based catalysts during anodic oxygen evolution reaction (OER), the atomic structure of the anodic catalysts’ surface often undergoes reconstruction to optimize the reaction path and enhance their catalytic activity. The design and maintenance of highly active sites during this reconstruction process remain critical and challenging for most OER catalysts. In this study, we explored the effects of crystal structures in pre-catalysts on surface reconstruction at low applied potential. Through experimental observation and theoretical calculation, we found out that catalysts with specific crystal structures exhibit superior surface remodeling ability, which enables them to better adapt to the conditions of the oxygen evolution reaction and achieve efficient catalysis. The discharge process enables the formation of abundant phosphorus vacancies on the surface, which in turn affects the efficiency of the entire oxygen evolution reaction. The optimized crystal structure of the catalyst results in an increase as high as 58.5 mA/cm2 for Ni5P4, which is twice as high as that observed for Ni2P. These results provide essential theoretical foundations and technical guidance for designing more efficient catalysts for oxygen evolution reactions.

Synergistic modulation of the d-band center in Ni3S2 by selenium and iron for enhanced oxygen evolution reaction (OER) and urea oxidation reaction (UOR)

Efficient production of green hydrogen energy is crucial in addressing the energy crisis and environmental concerns. The oxygen evolution reaction (OER) poses a challenge in conventional overall water electrolysis due to its slow thermodynamically process. Urea oxidation reaction (UOR) offers an alternative anodic oxidation method that is highly efficient and cost-effective, with favorable thermodynamics and sustainability. Recently, there has been limited research on bifunctional catalysts that exhibit excellent activity for both OER and UOR reactions. In this study, we developed a selenium and iron co-doped nickel sulfide (SeFe-Ni3S2) catalyst that demonstrated excellent Tafel slopes of 53.9 mV dec−1 and 16.4 mV dec−1 for OER and UOR, respectively. Density Functional Theory (DFT) calculations revealed that the introduction of metal (iron) and nonmetallic elements (selenium) was found to coordinate the d-band center, resulting in improved adsorption/desorption energies of the catalysts and reduced the overpotentials and limiting potentials for OER and UOR, respectively. This activity enhancement can be attributed to the altered electronic coordination structure after the introduction of selenium (Se) and iron (Fe), leading to an increase in the intrinsic activity of the catalyst. This work offers a new strategy for bifunctional catalysts for OER and UOR, presenting new possibilities for the future development of hydrogen production and novel energy conversion technologies It contributes towards the urgent search for technologies that efficiently produce green hydrogen energy, providing potential solutions to mitigate the energy crisis and protect the environment.

Experimental investigation of degradation mechanism in proton exchange membrane water electrolyzer under prolonged and severe bubble accumulation condition

Proton exchange membrane water electrolyzer (PEMWE) exhibits significant potential as a technology for hydrogen production driven by sustainable energy sources. In this study, the performance degradation characteristics of PEMWE under severe bubble accumulation condition lasting 100 h were investigated through in-situ and ex-situ characterization techniques. The results show that an increasing performance disparity with higher voltage, notably at lower temperatures, reaching a 58.2 % current density degradation rate at 50 °C and 2.0 V. Electrochemical impedance spectroscopy (EIS) analysis suggests that electrolyzer performance degradation is mainly due to increased charge transfer impedance, especially at the anode. In addition, the degraded electrolyzer exhibits a significant delay in reaching a stable current density during the abrupt voltage loading process, and its Tafel slope and electrochemically active surface area (ECSA) increased and decreased by 12.8 % and 13.5 %, respectively. Based on scanning electron microscopy (SEM) images, post-experiment analysis reveals pronounced thinning and noticeable cracks in both cathode and anode catalyst layers near the outlet, particularly on the anode side. Additionally, energy dispersive spectroscopy (EDS) mappings and transmission electron microscopy (TEM) images confirm substantial Pt/C and IrO2 catalyst particle dissolution, migration, and agglomeration. The findings of this study contribute to enhancing understanding of the performance degradation mechanisms in PEMWE.

Structural optimization and electrocatalytic hydrogen production performance of carbon-based composites: A mini-review

The energy demand has increased significantly in recent years and it is urgent to develop a renewable energy system that is highly efficient and non-noble metal-based. Hydrogen energy is an environmentally friendly energy source with abundant resources, which can be used to solve the problem of high energy demand without greenhouse gas emissions. However, the development of catalysts for hydrogen production technology by electrolysis of water is slow, mainly due to the complexity of the electrolysis hydrogen generation process, low hydrogen production efficiency, weak electrode material activity and high cost. Among the non-noble metal-based catalysts, carbon-based materials have high conductivity, tunable chemical bonding, and easily modified morphology, making them beneficial to achieving efficient hydrogen production, though pure carbon composites suffer from few surface-active sites and unmoderated hydrogen bonding energy, which need to be further optimized. The principle of electrocatalytic hydrogen production from the perspectives of reaction thermodynamics and kinetics is analyzed and discussed in this paper. Thermodynamics of electrocatalytic hydrogen production is reflected by the Gibbs free energy of hydrogen adsorption (ΔGH*) and electrode potential (E). Reaction kinetics of the electrocatalytic hydrogen production process are reflected by overpotential, Tafel slope and exchange current density. Structural optimization methods of carbon-based composite materials and hydrogen production performance after structural optimization are also summarized. Structural optimization methods of carbon-based composite materials mainly include introducing active sites, improving conductivity, increasing specific surface area and introducing self-supporting materials. Finally, prospects are proposed for the development direction and existing problems of electrocatalytic hydrogen production performance of carbon-based composites.

Design and modeling of a co-flow reactor for turquoise hydrogen production

This work focuses on the design of a reactor for producing clean hydrogen from methane pyrolysis in the form of the so-called “turquoise hydrogen”. In addition to its simple geometry, the fundamental concept and the main novelty of the proposed method rely on using part of the methane to produce the required heat needed for the thermal decomposition of methane (TDM). The reactor configuration for hydrogen production is shown to produce significant advantages in terms of greenhouse gas (GHG) emissions. A reactive flow CFD model incorporating also soot formation mechanism has been first developed and validated with experimental results available in the literature and then used to design and characterize the performances of proposed reactor configuration. 3D CFD simulations have been carried out to predict the behavior of the reactor configuration; a sensitivity analysis is used for clearing the aspect related to key environmental parameters, e.g., the global warming impact (GWI). The real potential of the proposed design resides in the low emissions and high efficiency with which hydrogen is produced at the various operating conditions (very flexible reactor), albeit subject to the presence of carbon by-product. This suggests that this type of methane conversion system could be a good substitute for the most common hydrogen production technologies.

First-principles calculation on electronic properties of hydrogen evolution reaction of Ni-based electrode surfaces with different monatomic doping

At present, the hydrogen evolution reaction (HER) of Ni-based electrode has an important influence on water electrolysis hydrogen production technology, involving complex electrochemical process of electrode. In this project, Materials Studio (MS) software was used to design and construct Ni-based electrode surface (NES) models with monatomic Mo, Co, Fe, Cr doping, and the NES models attached 1 H atom and 2H atoms were denoted as the NES-H models and NES-2H model, respectively. Then the first-principles calculation was carried out.The results showed that the doping of different atoms can effectively change the work function of the pure Ni. In the charge transfer process of the four NES-2H models, the distance between the two H atoms is most affected by Mo doping, and they leave the Ni electrode surface as a single H ion, respectively, while the effect on Co, Fe and Cr doping is relatively consistent, and they leave the Ni electrode surface with H2 molecules, respectively. The doping of four single atoms changes the distance of valence band (VB) top and conduction band (CB) bottom from Fermi level in NES, NES-H and NES-2H models, and affects the HER, in which Mo doping has the greatest effect. The TDOS of the above models is mainly derived from the PDOS of the d orbitals of the doped atoms and Ni atoms. The results will provide a theoretical basis for the research and development of Ni-based electrode materials in HER.

Techno-Economic Analysis of Heat-Assisted Hydrogen Production from Nuclear Power

To play a full role in decarbonisation, hydrogen must be produced economically at scale; the role of nuclear power is interesting to national governments as it is capable of supplying both low-carbon electricity and high-quality heat. Depending on the hydrogen production technology choice, a plant may require electricity and/or heat input. This techno-economic evaluation considers not only the costs of the hydrogen plant itself but also the costs of the power supply it requires. This paper calculates cost estimates for HTSE (High Temperature Steam Electrolysis) coupled with nuclear heat and electricity, and a thermochemical SI (Sulphur Iodine) cycle coupled with nuclear heat, based on the predictions of technical process models. These estimates are then compared to estimates made elsewhere for the costs of using wind with low temperature liquid water electrolysis, and steam methane reformation with carbon capture. This analysis led to the identification of the conditions under which nuclear-heat-coupled hydrogen production would be competitively priced. Estimates for nuclear-coupled LCOH2 (levelised cost of hydrogen) in 2050 range from 2.14 to 1.24 £/kg for HTSE, and from 2.88 to 0.89 £/kg for the SI cycle. There is still a great deal of uncertainty around the efficiency of SI and how it may improve over time, and this limits the accuracy to which the LCOH2 can be predicted.

Silk derived electrospun carbon nanofibers loaded with CoS nanoparticles as efficient hydrogen evolution reaction catalysts in acidic and alkaline media

The design of a stable and efficient hydrogen evolution catalyst across the entire pH range is of significant importance for the development of hydrogen production technology by electrocatalytic water splitting. This study chose biomass silk fibroin protein as the electrospinning raw material, synthesizing a hybrid membrane of CoS@carbon nanofibers (CNF) with a layered core–shell structure through simple carbonization and hydrothermal treatment. The CoS nanoparticles can grow uniformly and densely on the CNF. By varying the concentrations of hexahydrate cobalt nitrate (Co(NO3)2·6H2O) and thiourea (CH4N2S), the morphology of the synthesized CoS nanoparticles on CNF can be controlled. Different microscopic morphologies lead to differences in the activity of the hydrogen evolution reaction (HER), attributed to variations in the exposed active sites for different morphologies. Compared to pure CNF, the CoS-2@CNF hybrid membrane exhibits excellent HER activity in both acidic and alkaline electrolytes. This highlights the synergistic catalytic effect between CNF and CoS particles. This work provides guidance for the rational design of bio-based catalysts with excellent performance.

Systems design and techno-economic analysis of a novel cryogenic carbon capture process integrated with an air separation unit for autothermal reforming blue hydrogen production system

In the transition of the global energy paradigm toward decarbonization, hydrogen is expected to play a crucial role as an energy vector. To enhance the sustainability of hydrogen as an energy source, it is important to reduce costs and carbon emissions in the hydrogen production. Among various hydrogen production technologies, the autothermal reforming (ATR)-based blue hydrogen production method can stand out as a promising option in terms of both economic and environmental considerations. However, there are several bottlenecks: (i) ATR requires an air separation unit that increases the cost burden, and (ii) conventional amine-based carbon capture method consumes a significant amount of energy. To address these bottlenecks, this study proposes a novel cryogenic carbon capture process for ATR-based blue hydrogen production. In the proposed process, air separation unit are utilized not only for oxygen production but also for carbon capture. The compressed air from the air separation unit provides cooling energy to the mixture gas, leading to solidification and separation of carbon dioxide. Despite imposing an additional burden on the air separation unit, it significantly reduces the energy and cost associated with carbon capture. Consequently, there exists a trade-off relationship between the increased load on the air separation unit and the decreased load in carbon capture. This trade-off was evaluated by comparing it with the conventional absorption-based carbon capture process in terms of energy and economic aspects. The proposed process exhibits a 36.4% reduction in total energy consumption, with a particularly approximately 49.5% decrease in the energy consumed for carbon capture (0.278 kW h/kg-CO2). The economic performance indicates an 11% decrease in the levelized cost of hydrogen (1.62$/kg-H2), and a 45.3% decrease in CO2 avoidance cost (40.1$/kg-CO2). The captured solid CO2 can offer advantages during storage and transportation. Furthermore, the potential utilization of cooling energy of solid CO2 from an end-user perspective is expected to contribute to the establishment of a new industrial value chain.

Optimally Splitting Solar Spectrums by Concentrating Solar Spectrums Splitter for Hydrogen Production via Solid Oxide Electrolysis Cell

The concentrating solar spectrums splitter (CSSS)-driven solid oxide electrolysis cell (SOEC) is an attractive technology for green hydrogen production. The CSSS mainly comprises a concentrating photovoltaic (CPV), which converts sunlight with shorter wavelengths into electricity, and a concentrating solar collector (CSC), which converts the remaining sunlight into heat. However, the optimal splitting of the solar spectrums is a critical challenge that directly impacts the efficiency and normal operation of the SOEC. To address this challenge, a mathematical model integrating the CSSS with the SOEC is developed based on principles from thermodynamics and electrochemistry. By analyzing the requirements of electricity and heat for the SOEC, the model determines the optimal configuration and operational parameters. The results show that the anode-supported type, higher operating temperature, larger inlet flow rate of water, higher operating pressure of the SOEC, higher operating temperature of the CSC, and larger electric current of the CPV contribute to allocating more solar spectrums to the CSC for heat generation. However, the greater effectiveness of the heat exchangers, higher operating temperature, and larger optical concentration ratio of the CPV exhibit contrasting effects on the spectrum allocation. The obtained results provide valuable theoretical guidance for designing and running the CSSS for hydrogen production through SOEC.