Hydrogen Production Technologies Research Articles

Anion Exchange Membrane Water Electrolysis at 10 A·cm-2 Over 800 Hours.

Anion exchange membrane water electrolyzer (AEMWE) is a potentially cost-effective technology for green hydrogen production. Although the normal current densities of AEMWEs are below 3 A·cm-2, operating them at higher current densities represents an efficient, but little-explored approach to decrease the total cost of hydrogen production. We show here that a benchmark AEMWE has an operational lifetime of only seconds at an ultrahigh current density of 10 A·cm-2. By using a more conductive and robust AEM, and judicious choices of ionomers, catalyst, and porous transport layer, we have developed AEMWEs that stably operate at 10 A·cm-2 with extended lifetimes. The optimized AEMWE has an operational lifetime of more than 800 hours, a 5-order magnetite improvement over the current benchmark. The cell voltage is only 2.3 V at 10 A·cm-2, comparable to those of the state-of-the-art devices operating at current densities lower than 3 A·cm-2. This work demonstrates the potential of ultrahigh current density AEMWEs.

Direct Hydrogen Production Promoted by Laser-Induced Water Plasma.

Hydrogen, as a clean energy carrier, plays an important role in addressing the current energy and environmental crisis. However, conventional hydrogen production technologies require extreme reaction conditions, such as high temperature, high pressure, and catalysts. Herein, we study the microscopic mechanism of laser-induced water plasma and subsequent H2 production with real-time time-dependent density functional theory simulations and ab initio molecular dynamics simulations. The results demonstrate that intense laser excites liquid water to generate nonequilibrium plasma in a warm-dense state, which constitutes a superior reaction environment. Subsequent annealing leads to the recombination of energetic reactive particles to generate H2, O2, and H2O2 molecules. Annealing rate and laser wavelength are shown to modulate the product ratio, and the energy conversion efficiency can reach ∼9.2% with an annealing rate of 1.0 K/fs. This work reveals the nonequilibrium atomistic mechanisms of hydrogen production from laser-induced water plasma and shows far-reaching implications for the design of optically controllable hydrogen technology.

THE IMPORTANCE OF EXPANDING RESEARCH ON THE SERPENTINIZATION OF OPHIOLITE ROCKS BY NATURAL “WHITE” HYDROGEN FOR KAZAKHSTAN

In Kazakhstan, options and regions for hydrogen production are being considered, including in Western Kazakhstan, the Mangystau region, using the water of the Caspian Lake. The current advanced hydrogen production technologies, including green hydrogen, are very expensive, requiring billions of dollars of investment and potentially creating difficulties for the local population and nature, ecology, flora and fauna. At the same time, geological studies of alternative hydrogen production options in Kazakhstan are poorly developed. Kazakhstan needs and is currently very important to study serpentinization of ophiolite rocks using natural «white» hydrogen. In many countries, there is practically a «gold rush» now, hydrogeologists are conducting research on the search for natural «white» hydrogen. Hydrogeologists have now discovered numerous sources of natural hydrogen in geological environments from Mali to Switzerland, France, Germany, the USA, Canada, and Australia. More than 50 companies have sprung up to discover and mine it. A natural hydrogen well operates in Mali to provide energy to a local city with a population of about 4,000 people for free and forever. Unlike other geological fuels, which are formed over millions of years, natural hydrogen is generated by mixing water and iron particles, serpentinization of ophiolite rocks, and is renewable on the scale of human time, and not in geological epochs. Alternative options for the production and use of hydrogen are presented in this review, including various types of hydrogen, black, gray, green, blue, turquoise, pink and yellow, depending on the method of its extraction and production. Kazakhstan, with the richest natural ore reserves, including coal and polymetals, where ophiolite rocks may be located, may well have deposits of natural «white» hydrogen, such geological studies in Kazakhstan are poorly developed.

Towards a more sustainable hydrogen energy production: evaluating the use of different sources of water for chloralkaline electrolyzers

Water scarcity is becoming a serious threat for the implementation of energy storage devices based on hydrogen in the inland of dry regions, because of the difficulties in finding appropriate sources of water and the important environmental problem associated with the discharge of rejection saline streams produced during the purification of water. This becomes an opportunity for chloralkaline technology in which the quality of water used is lower than the required in other hydrogen production technologies. This work compares the performance of chloralkaline electrolyzers fed with different solutions of NaCl (from brackish water to brines) with that obtained feeding two natural water samples (seawater and porewater) and three processed waters (rejections streams of the electrodialysis, reverse osmosis of the porewater and a real rejection of the reverse osmosis of a vineyard). All tests were made with a lab-scale 3-D printed cell where, in addition, the performance of Ti/RuO2 and Pb/PbO2 anodes were compared, being always better the results obtained in the tests made with the Ti/RuO2 electrode. Results obtained indicate that efficiencies reached using these alternative sources are lower than those which can be reached using synthetic brines that, in turn, were very near to the standards reached in the chloralkaline industry. In the case of hydrogen production, the maximum values were obtained for seawater, reaching efficiencies proximate to 8.0 mg H2 (Wh)-1. Rejection streams of desalination processes were found to be less efficient, attaining values in the range 2 and 4 mg H2 (Wh)-1. Regarding the production of chlorine and caustic soda, better performances were reached again with seawater (161.7 mg Cl2 (Wh)-1 and 0.092 mg OH- (Wh)-1 ) and with the rejection of the electrodialysis, which also reached sound values of 90.4 mg Cl2 (Wh)-1 and 0.107 mg OH- (Wh)-1. Results obtained are promising and indicate a path that must be further worked for the implementation of a greener water management strategy in the hydrogen -based energy storage technology.

Comparative life cycle analysis of electrolyzer technologies for hydrogen production: Manufacturing and operations

Comparative life cycle analysis of electrolyzer technologies for hydrogen production: Manufacturing and operations

High-performance porous 3D Ni skeleton electrodes for the oxygen evolution reaction

A key component of green hydrogen production technologies is the fabrication of large-scale porous transport layer (PTL) for use in anion electrolyte membrane water electrolysers (AEMWEs). One strategy to achieve that goal is to manufacture Ni-based 3D electrode skeletons that can be further catalyzed to achieve high current densities at low overpotentials. In the present work, shock-wave induced spray (SWIS) and cold spray (CS) deposition techniques were used to prepare 20 cm2 Ni-based electrode skeletons. In our experimental conditions, the porosity of coatings prepared using the SWIS deposition system and Ni powders with particle sizes D50 = 32 and 75 μm never exceeded 28%. Higher porosity could only be achieved using the CS deposition system and a spheroidal Ni–Al powder, whose particles consist of an aluminum core encapsulated in a nickel shell. After Al leaching in an alkaline solution, the resulting electrodes showed good mechanical and structural integrity with up to 41% porosity. The electrochemical active surface area of the most porous electrodes is a factor of 2100 larger than a polished Ni plate, and it has superaerophobic properties with a captive air bubble contact angle of 151°. During 1 h of electrolysis, the overpotential at 100 mA cm−2 of the most active leached Ni–Al cold spray deposited electrode was 330 mV, compared to 380 mV for a Ni foam electrode.

Greenhouse Gas Emissions and Net Energy Production of Dark Fermentation from Food Waste Followed by Anaerobic Digestion

There are diverse estimations regarding the carbon reduction effects of alternative hydrogen production technologies. This study assessed the greenhouse gas (GHG) emissions and energy balance of a two-stage process combining dark fermentative hydrogen production and anaerobic digestion from food waste using the cradle-to-gate life cycle assessment (LCA). The system boundary included collection and transportation, pretreatment and feedstock storage, dark fermentation, H2 purification, anaerobic digestion and heat and power generation and the estimated GHG emission was compared with a single anaerobic digestion of food waste. GHG emission of the biohydrogen production was estimated as 2.48 kg CO₂-eq per kg H₂ without considering avoided emissions from heat and power generation. The environmental impacts were majorly influenced by electricity use. The net energy ratio of the two-stage process was calculated to be 8.18, confirming a net energy gain and the potential GHG emission avoidance for electricity and heat use. Given that the single-stage anaerobic digestion of 16 tons of food waste is replaced by the two-stage dark fermentation process, 76.6 kg CO₂-eq would be avoided. Sensitivity analysis revealed that energy-saving strategies are the most sensitive factors for achieving positive net energy production and low global warming potential.

Theoretical design and synthesis of Co30Ni60/CC for high selective methanol oxidation assisted energy-saving hydrogen production

The integration of methanol oxidation reaction (MOR) with hydrogen evolution reaction (HER) represents an advanced approach to hydrogen production technology. Nonetheless, the rational design and synthesis of bifunctional catalysts for both MOR and HER with exceptional activity, stability and selectivity present formidable challenges. In this work, firstly, density functional theory (DFT) was utilized to design and evaluate material models with high performance for both MOR and HER. Secondly, guided by DFT, Co30Ni60/CC (CC, carbon cloth) composites with a leaf-like nanosheet structure were successfully fabricated via electrodeposition. In the MOR process, Ni acts as the predominant active center, while Co amplifies the electrochemically active surface area (ECSA) and enhances the selectivity of methanol oxidation. Conversely, in the HER process, Co serves as the primary active center, with Ni augmenting the charge transfer rate. The electrochemical results demonstrate that Co30Ni60/CC exhibits exceptional performance in both MOR and HER at a current density (j) of 10 mA cm−2, with peak potentials of 1.323 V and −95 mV, respectively. Additionally, it shows remarkable selectivity for the oxidiation of methanol to high value-added formic acid. Thirdly, following a 100 h chronopotentiometry (CP) test, the required potential demonstrates an increase of 4.9 % (MOR) and 8.1 % (HER), signifying the superior stability of Co30Ni60/CC compared to those reported in the literature. The exceptional performance of Co30Ni60/CC can be primarily attributed to that the leaf-like nanosheets structure not only exposes a plethora of active sites but also facilitates electrolyte diffusion, the monolithic structure prepared by electrodeposition enhances its stability, and the transfer of electrons from Co to Ni regulates its electronic structure, as corroborated by X-ray photoelectron spectroscopy (XPS) and density of states (DOS) analyses. Finally, at the same j, the voltage required by the Co30Ni60/CC||Co30Ni60/CC electrolytic cell, powered by an electrochemical workstation, is 198 mV lower than that required for alkaline water-splitting. Meanwhile, at higher j (100 mA cm−2), the electrolytic cell exhibits sustained and stable operation for 150 h, enabling high-efficiency hydrogen production and the synthesis of high value-added formic acid.

Construction of novel β-XY (X = Ge, Sn, Y = S)/g-C3N4 heterostructures: efficient visible light-driven water splitting catalysts

The logical design of inexpensive, non-polluting, and extremely effective photocatalysts is a crucial step toward achieving clean energy. The currently low solar-to-hydrogen (STH) conversion efficiency (ηSTH) makes hydrogen production technologies less than optimal. Herein, novel β-XY (X = Ge, Sn, Y = S)/g-C3N4 heterostructures have been constructed. Among them, the β-SnS/g-C3N4 exhibits low carrier recombination, and its geometry, optoelectronic properties, as well as the thermodynamic feasibility of its reaction, have been thoroughly examined through DFT calculations. The results demonstrate that the β-SnS/g-C3N4 heterostructure is a type-II heterostructure, exhibiting an indirect band gap of 2.57 eV. Photocatalysis is more efficient because of the built-in electric field that extends from the g-C3N4 monolayer to the β-SnS monolayer, effectively separating electrons and holes. The continuously decreasing free energy validates the thermodynamic spontaneity of water splitting. Additionally, the heterostructure demonstrates robust absorption in both the visible and UV ranges. Notably, the ηSTH of 15.54 % underscores the commercial viability of this material. These findings thus suggest that β-SnS/g-C3N4 heterostructure is a good candidate material for water splitting via photocatalysis.

Fabrication of In-doped CdSe/Zn3In2S6 type II heterojunction composite for efficient photocatalytic hydrogen evolution

Conversion of water into renewable hydrogen energy using solar energy is one of the ideal methods to address the current environmental pollution and increasing energy demand. Thus developing the photocatalyst with high efficiency, stability, and a low electron-hole recombination rate becomes very important. In this paper, Zn3In2S6 microspheres were synthesized by hydrothermal method, and then In-doped CdSe nanoparticles were loaded on the surface of Zn3In2S6 microspheres to form Cd0.9In0.1Se/Zn3In2S6 type II heterojunction. Under simulated sunlight irradiation, the photocatalytic hydrogen production of Cd0.9In0.1Se/Zn3In2S6 reached 11.41 mmol h−1 g−1, which was 4.61 times and 1.97 times that of Cd0.9In0.1Se and Zn3In2S6, respectively. The experimental results showed that the formation of type II heterojunction could improve the photocatalytic hydrogen production efficiency by shortening the charge transport distance and inhibiting the recombination of electron-hole pairs. This work will provide new ideas and insights for the development of photocatalytic hydrogen production technology.

Upcycling of Spent LiFePO4 Cathodes to Heterostructured Electrocatalysts for Stable Direct Seawater Splitting.

The pursuit of carbon-neutral energy has intensified the interest in green hydrogen production from direct seawater electrolysis, given the scarcity of freshwater resources. While Ni-based catalysts are known for their robust activity in alkaline water oxidation, their catalytic sites are prone to rapid degradation in the chlorine-rich environments of seawater, leading to limited operation time. Herein, we report a Ni(OH)2 catalyst interfaced with laser-ablated LiFePO4 (Ni(OH)2/L-LFP), derived from spent Li-ion batteries (LIBs), as an effective and stable electrocatalyst for direct seawater oxidation. Our comprehensive analyses reveal that the PO4 3- species, formed around L-LFP, effectively repels Cl- ions during seawater oxidation, mitigating corrosion. Simultaneously, the interface between in situ generated NiOOH and Fe3(PO4)2 enhances OH- adsorption and electron transfer during the oxygen evolution reaction. This synergistic effect leads to a low overpotential of 237 mV to attain a current density of 10 mA cm-2 and remarkable durability, with only a 3.3 % activity loss after 600 h at 100 mA cm-2 in alkaline seawater. Our findings present a viable strategy for repurposing spent LIBs into high-performance catalysts for sustainable seawater electrolysis, contributing to the advancement of green hydrogen production technologies.

Upcycling of Spent LiFePO4 Cathodes to Heterostructured Electrocatalysts for Stable Direct Seawater Splitting

AbstractThe pursuit of carbon‐neutral energy has intensified the interest in green hydrogen production from direct seawater electrolysis, given the scarcity of freshwater resources. While Ni‐based catalysts are known for their robust activity in alkaline water oxidation, their catalytic sites are prone to rapid degradation in the chlorine‐rich environments of seawater, leading to limited operation time. Herein, we report a Ni(OH)2 catalyst interfaced with laser‐ablated LiFePO4 (Ni(OH)2/L‐LFP), derived from spent Li‐ion batteries (LIBs), as an effective and stable electrocatalyst for direct seawater oxidation. Our comprehensive analyses reveal that the PO43− species, formed around L‐LFP, effectively repels Cl− ions during seawater oxidation, mitigating corrosion. Simultaneously, the interface between in situ generated NiOOH and Fe3(PO4)2 enhances OH− adsorption and electron transfer during the oxygen evolution reaction. This synergistic effect leads to a low overpotential of 237 mV to attain a current density of 10 mA cm−2 and remarkable durability, with only a 3.3 % activity loss after 600 h at 100 mA cm−2 in alkaline seawater. Our findings present a viable strategy for repurposing spent LIBs into high‐performance catalysts for sustainable seawater electrolysis, contributing to the advancement of green hydrogen production technologies.

Rational Design of Heterostructured MXene‐based Nanomaterials in Electrocatalytic Water Splitting

Hydrogen energy is widely considered the potential energy resource for energy conversion systems owing to its high energy density and pollution‐free nature. This review provides a comprehensive overview of recent advancements in heterostructured MXenes for hydrogen production. The fundamental properties of MXenes and their unique contribution to catalytic application are addressed, including the synthesis strategies, interlayer modification, and hybridization with other materials to enhance catalytic performance. Comparative analysis highlights the effect of different heterostructured MXenes on enhanced catalytic efficiency by tuning their electronic properties and increasing the surface interactions. We provide the future research direction and challenges of functionalized MXene composites, such as material stability, scalability, and environmental impact. Ultimately, the recent progress underscores the potential of heterostructured MXenes in advancing hydrogen production technologies, offering a path toward cleaner energy solutions.

Impacts of process parameters on diesel reforming via interpretable machine learning

Diesel reforming is a promising hydrogen production technology used for the clean energy conversion of high-carbon-content fuels. Although the reaction system has been established, predicting the optimal reaction conditions for the system remains challenging. Here, we obtained a set of 675 data points from Aspen Plus simulations and trained regression models to predict the reaction condition ranges that yield the highest hydrogen production in diesel reforming. The ETR model achieved the best predictive performance, with an R2 value of 0.99. Interpretable machine learning methods revealed that temperature is a crucial feature determining the baseline hydrogen yield of the diesel reforming reaction, while the steam-to-carbon ratio is key to enhancing hydrogen yield. Our exploratory study underscores the ability of data-driven ML models to uncover the condition-yield relationship in catalytic diesel reforming for hydrogen production by isolating the effects of individual design parameters, a feat that is difficult to achieve through experimental means.

Enriching wind power utility through offshore wind-hydrogen-chemicals nexus: Feasible routes and their economic performance

The offshore wind-hydrogen strategy is crucial for achieving carbon neutrality, yet faces challenges like wind power variability, surplus hydrogen, and elevated costs. Recently, linking offshore wind, hydrogen, and chemicals is proposed to address these challenges. However, there is a lack of a comprehensive techno-economic analysis of this nexus. This study, as one of the first attempts, performs the techno-economic analysis of 8 feasible offshore wind-hydrogen-chemical nexus routes, in which factors of technology, economics, and financial policy are considered. The research indicates that Route 7, which incorporates offshore wind power utilizing proton exchange membrane technology for hydrogen production and blends it with natural gas on offshore platforms, demonstrates the most cost-effective outcome. The key factors influencing the cost reduction of these routes encompass the green hydrogen price, capital costs, internal rate of return, electricity price, value-added tax rate, and loan ratio. Among these, the green hydrogen price is the primary determinant influencing the cost of green products. If the price of green hydrogen decreases to 2.19 USD/kg, green synthetic ammonia can meet the current standard of 605.47 USD/t. Finally, the results can provide important reference to support stakeholders for seeking cost-effective routes of offshore wind-hydrogen-chemical nexus in China and other regions.

Research Progress on Characteristics of On‐Line Hydrogen Production by Methanol Steam Reforming

On‐line hydrogen production via methanol steam reforming (MSR) has gained considerable interest due to its high efficiency, affordability, and eco‐friendliness. Currently, this technology has been widely applied in the industry and has become an important method for hydrogen energy production. However, there are still some issues with this technology, such as short catalyst lifespan and CO pollution, which require further research and improvement. This article provides a comprehensive review of the research progress made in this field, with a particular focus on the catalyst development, reaction mechanism, theoretical calculation, and reactor design. Additionally, the challenges and prospects of on‐line hydrogen production by MSR are also discussed. In conclusion, MSR technology for hydrogen production has vast application prospects and development potential. It will be further explored in‐depth and extensively in future research.

Mo-Induced Surface Reconstruction in Ni/Co-OOH Prickly Flower Clusters for Improving the Hydrogen Production in Alkaline Seawater Splitting.

Seawater electrolysis is the most promising technology for hydrogen production, in which surface reconstruction on the interface of electrode/electrolyte plays a crucial role in activating the catalytic reactions with a low activation energy barrier. Herein, an efficient Mo modifying NiCoMo prickly flower clusters electrocatalyst supported on nickel foam (Mo-doped Ni/Co-OOH prickly flower clusters) is obtained, which serves as an eminently active and durable catalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) due to the surface reconstruction during the alkaline seawater electrolysis with ultralow overpotentials. It just requires a cell voltage of 1.52V to achieve the current density of 10mAcm-2 for water electrolysis along with robust durability over 30h. Mo doping effectively regulates the surface reconstruction of Ni/Co-OOH, which facilitates the adsorption of oxygen-containing intermediates on the active center, and the nonhomogeneous interface induces charge rearrangement for the catalytic process to improve efficiency, providing a new strategy for revealing the seawater electrolytic mechanism.

Coordinated planning model for multi-regional ammonia industries leveraging hydrogen supply chain and power grid integration: A case study of Shandong

With the advancement of green hydrogen production technology, power-to-ammonia (P2A) has emerged as a pivotal approach for consuming large-scale renewable resources. However, the inherent intermittency of wind and solar resources leads to a spatial and temporal mismatch between supply and demand, rendering effective integration within a single region challenging and necessitating cross-regional collaborative planning. To address this, we propose a coordinated planning model for a multi-regional ammonia industrial system (MAIS) that leverages the integration of a hydrogen supply chain (HSC) and power grid (PG), termed HSC-PG-MAIS. During the modeling of the HSC, we developed a novel hydrogen truck transportation model that allows trucks to serve as both hydrogen storage and transportation resources. Furthermore, considering the cooperative relationships among ammonia industrial systems in different regions, we proposed a Nash bargaining method based on the magnitude of interactive value contributions to equitably allocate the cooperation costs and benefits of the MAIS. Finally, real data from Shandong Province in China is used to validate the effectiveness and significance of the proposed model and strategy. The results indicate that the proposed model can effectively reduce the overall operating costs of the system and enhance its flexibility, providing valuable insights into exploring the collaborative potential of large-scale renewable resources across regions.

Regulating Strain and Electronic Structure of Indium Tin Oxide Supported IrOx Electrocatalysts for Highly Efficient Oxygen Evolution Reaction in Acid.

The development of proton exchange membrane water electrolysis is a promising technology for hydrogen production, which has always been restricted by the slow kinetics of the oxygen evolution reaction (OER). Although IrOx is one of the benchmark acidic OER electrocatalysts, there are still challenges in designing highly active and stable Ir-based electrocatalysts for commercial application. Herein, a Ru-doped IrOx electrocatalyst with abundant twin boundaries (TB-Ru0.3Ir0.7Ox@ITO) is reported, employing indium tin oxide with high conductivity as the support material. Combing the TB-Ru0.3Ir0.7Ox nanoparticles with ITO support could expose more active sites and accelerate the electron transfer. The TB-Ru0.3Ir0.7Ox@ITO exhibits a low overpotential of 203 mV to achieve 10 mA cm-2 and a high mass activity of 854.45 A g-1noblemetal at 1.53 V vs RHE toward acidic OER, which exceeds most reported Ir-based OER catalysts. Moreover, improved long-term stability could be obtained, maintaining the reaction for over 110 h at 10 mA cm-2 with negligible deactivation. DFT calculations further reveal the activity enhancement mechanism, demonstrating the synergistic effects of Ru doping and strains on the optimization of the d-band center (εd) position and the adsorption free energy of oxygen intermediates. This work provides ideas to realize the trade-off between high catalytic activity and good stability for acidic OER electrocatalysts.

Optimization of a novel hydrogen production process integrating biomass and sorption-enhanced reforming for reduced CO2 emissions

Recently, there has been a growing demand for clean and sustainable energy sources to bridge the energy gap. Hydrogen has emerged as an attractive and environmentally friendly energy carrier due to its potential for high energy efficiency and minimal pollution generation, making it a promising alternative to fossil fuels. This study proposes and investigates a novel coupled process that utilizes chemical looping technologies for hydrogen production, simultaneously utilizing natural gas and biomass as feedstocks. The primary objective of this research is to develop a process model that maximizes hydrogen production while minimizing carbon dioxide emissions. Aspen Plus version 10 was employed to simulate and analyze the proposed process configuration to achieve this. One of the proposed process's key advantages is its competitiveness compared to conventional steam methane reforming (SMR) processes, which are widely used in industry. The novel process offers significant benefits, such as enhanced hydrogen purity and reduced CO2 content in the product gas. The simulation results obtained from Aspen Plus reveal the successful production of highly pure hydrogen with a molar ratio of H2/CO equal to 268 and syngas with a molar ratio of H2/CO approximately equal to 1. Additionally, the process demonstrates the capability to produce highly high-purity hydrogen with a molar ratio of H2/CO equal to 155,000 in three-section reactors.