Hydrogen Production Research Articles

State-of-the-art and perspectives of hydrogen generation from waste plastics.

Waste plastic utilization and hydrogen production present significant economic and social challenges but also offer opportunities for research and innovation. This review provides a comprehensive analysis of the latest advancements and innovations in hydrogen generation coupled with waste plastic recycling. It explores various strategies, including pyrolysis, gasification, aqueous phase reforming, photoreforming, and electrocatalysis. Pyrolysis and gasification in combination with catalytic reforming or water gas-shift are currently the most feasible and scalable technologies for hydrogen generation from waste plastics, with pyrolysis operating in an oxygen-free environment and gasification in the presence of steam, though both require high energy inputs. Aqueous phase reforming operates at moderate temperatures and pressures, making it suitable for oxygenated plastics, but it faces challenges related to feedstock limitations, catalyst costs and deactivation. Photoreforming and electrocatalytic reforming are emerging, sustainable methods that use sunlight and electricity, respectively, to convert plastics into hydrogen. Still, they suffer from low efficiency, scalability issues, and limitations to specific plastic types like oxygenated polymers. The challenges and solutions to commercializing plastic-to-hydrogen technologies, drawing on global industrial case studies have been outlined. Maximizing hydrogen productivity and selectivity, minimizing energy consumption, and ensuring stable operation and scaleup of plastic recycling are crucial parameters for achieving commercial viability.

Self-Powered Electrocatalytic Aldehyde Reforming Fuel Cell for Sustainable H2 Generation with ~200% Faradaic Efficiency.

Formaldehyde (HCHO), a promising yet enigmatic hydrogen carrier, presents both an intriguing opportunity and a formidable challenge to unlock its full potential of conversion and hydrogen (H2) generation while safeguarding environmental sustainability. This study rises to the challenge by pioneering a hybrid acid/alkali formaldehyde hydrogen production fuel cell (h-AAFHFC), an integrated system that integrates anodic partial electro-reforming of aldehydes at low potential with the cathodic hydrogen evolution reaction (HER). The device introduces a new self-powered paradigm for H2 generation, featuring high Faradaic efficiency (FE), co-generation of electricity and acetate, and seamless synergy with renewable energy sources, all while achieving zero carbon dioxide emissions. The h-AAFHFC attains an open-circuit voltage of 1.11 V and a peak power density of 94 mW cm-2, enabling simultaneous H2 production at both electrodes with an extraordinary FE of approximately 200%. This breakthrough marks a transformative shift, moving from traditional electricity-driven systems to self-sustaining H2 generation. Our work lays the foundation for an eco-friendly, sustainable approach to H2 production, advancing the transition toward a carbon-neutral energy future.

Machine Learning Stacked Model for Predicting Faradaic Efficiency in Electrochemical CO2 Reduction on Nitrogen-Doped Carbon.

Nitrogen-doped carbon materials are promising catalysts for electrochemical CO2 reduction (ECR), but achieving high Faradaic efficiency (FE) for CO production is challenging due to the competing hydrogen evolution reaction (HER). Conventional catalyst optimization approaches are often slow and labor-intensive. To overcome these limitations, we develop a machine learning-based stacked model to predict the Faradaic efficiency (FE) of CO in ECR, combining random forest (RF) and XGBoost (XGB) as base models with linear regression as a meta-model. This stacked approach significantly reduces overfitting, achieving R2 values of 0.98 for training and 0.91 for testing, compared to 0.99 (train) and 0.86 (test) using XGBoost alone with default parameters. SHAP (SHapley Additive exPlanations) analysis shows that pyridinic nitrogen plays a major role in increasing CO selectivity among the different nitrogen forms, while graphitic nitrogen is crucial for predicting hydrogen production during the HER. These findings highlight how machine learning accelerates catalyst design by providing insights into the roles of nitrogen configurations in tuning product selectivity. This study presents a novel, data-driven approach to electrocatalyst optimization, offering a pathway toward more effective CO2 reduction technologies.

Understanding the Sustainable Hydrogen Generation Potential for the Region of Bavaria, Germany via Bio-Waste Processing Using Thermochemical Conversion Technology

Future decarbonization targets demand a higher penetration of renewable energy (RE) sources into the system. However, challenges such as an uneven spatial and temporal distribution of various RE sources’ potential for green electricity (GE) generation demand alternative ways to store and later utilize the generated energy. In addition to that, sustainable development goals (SDGs) highlight the need for the responsible use of resources with increased recycling and a reduction in corresponding waste generation while ensuring access to affordable, reliable, sustainable, and modern energy for all. In this paper, an attempt is made to address both the issues of biodegradable waste (BW) processing and sustainable hydrogen (SH) production through it. Thermochemical conversion technology (TCC) and, within that, especially ‘thermocatalytic reforming’ (TCR®) technology have been explored as options to provide viable solutions. An added advantage of decentralized hydrogen production can be envisioned here that can also contribute to regional energy security to some degree. To analyze the concept, the Bavarian region in Germany, along with open-source data for bio-waste from two main sources, namely domestic household and sewage sludge (SS), were considered. Based on that, the corresponding regional hydrogen demand coverage potential was analyzed.

A Multi-State Rotational Control Strategy for Hydrogen Production Systems Based on Hybrid Electrolyzers

Harnessing surplus wind and solar energy for water electrolysis boosts the efficiency of renewable energy utilization and supports the development of a low-carbon energy framework. However, the intermittent and unpredictable nature of wind and solar power generation poses significant challenges to the dynamic stability and hydrogen production efficiency of electrolyzers. This study introduces a multi-state rotational control strategy for a hybrid electrolyzer system designed to produce hydrogen. Through a detailed examination of the interplay between electrolyzer power and efficiency—along with operational factors such as load range and startup/shutdown times—six distinct operational states are categorized under three modes. Taking into account the differing dynamic response characteristics of proton exchange membrane electrolyzers (PEMEL) and alkaline electrolyzers (AEL), a power-matching mechanism is developed to optimize the performance of these two electrolyzer types under varied and complex conditions. This mechanism facilitates coordinated scheduling and seamless transitions between operational states within the hybrid system. Simulation results demonstrate that, compared to the traditional sequential startup and shutdown approach, the proposed strategy increases hydrogen production by 10.73% for the same input power. Moreover, it reduces the standard deviation and coefficient of variation in operating duration under rated conditions by 27.71 min and 47.04, respectively, thereby enhancing both hydrogen production efficiency and the dynamic operational stability of the electrolyzer cluster.

Effect of silicon doping in nanostructured hematite thin films for photoelectrochemical hydrogen generation

In this work, the researcher concentrated on the synthesis and analysis of the properties of Si-doped nanostructured hematite ([Formula: see text]-Fe2O[Formula: see text] thin films, aiming to use them as photoelectrodes in photoelectrochemical (PEC) cells for the production of hydrogen. Spray pyrolysis, deposition method is used for thin-film synthesis to achieve uniform, nanostructured layers with controllable doping levels. The confirmation of the hematite phase by XRD ensures that the desired [Formula: see text]-Fe2O3 structure was achieved in both doped and undoped films. Scanning Electron Microscopy (SEM) analysis, revealing surface morphology and nanoscale structures, provided insights into how Si-doping affected factors like grain size, porosity, etc. The significant visible light absorption observed ([Formula: see text]2.1[Formula: see text]eV) aligns well with the band gap of hematite, which is promising for PEC applications. Furthermore, the marked improvement in photocurrent — specifically, a threefold increase ([Formula: see text]680[Formula: see text] [Formula: see text]A/cm2 at 0.7[Formula: see text]V/SCE) at a 0.002 M Si-doping concentration highlights the effectiveness of Si doping by introducing favorable electronic changes, potentially increasing the conductivity of the hematite. The substitution of Fe[Formula: see text] ions by Si[Formula: see text] in the [Formula: see text]-Fe2O3 lattice likely contributes to enhanced charge separation and reduced recombination rates that are the critical factors in sustaining higher photocurrents.

S-Scheme CdS/Co₃S₄ Double-Shelled Hollow Nanoboxes for Enhanced Photocatalytic Hydrogen Evolution.

Developing S-scheme systems with high photocatalytic performance is crucial for long-term solar-to-hydrogen conversion. In this study, hollow cobalt tetrasulfide (Co3S4) nanoboxes (NBs), synthesized via sulfurization using zeolitic imidazolate framework (ZIF-67) as a template, are combined with cadmium sulfide (CdS) nanoparticles (NPs) to construct heterojunction photocatalysts under mild conditions. The optimized CdS/Co3S4 double-shelled nanoboxes (DSNBs) achieved a superior photocatalytic hydrogen production rate of 23.45mmol h-1 g-1 under visible light, approximately 24 times greater than that of pure CdS NPs. The apparent quantum efficiency (AQE) of CdS/Co3S4 DSNBs is 18.5 %. The distinctive hollow structure enhances visible-light-harvesting by exposing active sites, enabling multiple light reflections, and allowing the thin shells to shorten the transport distance for charge carriers, effectively minimizing charge recombination. The improved photoactivity results from the synergistic effects of the aligned bandgap structures, strong visible-light absorption, and interfacial interactions driven by the inherent electric field (IEF). The findings offer insights into designing efficient S-scheme heterojunction catalysts for sustainable hydrogen evolution through photocatalytic water splitting.

Interfacial-Free-Water-Enhanced Mass Transfer to Boost Current Density of Hydrogen Evolution.

The advancement of water electrolysis highlights the growing importance of electrolyzers capable of operating at high current densities, where mass transfer dynamics plays a crucial role. In the electrode reactions, the interfacial water is a key factor in regulating these dynamics. However, the potential of utilizing interfacial-free water (IFW) to modulate electrode behavior remains underexplored. Herein, we investigate the effect of interfacial water structure on hydrogen evolution reaction (HER) performance across different current density ranges, using designed platinum-coated nickel hydroxide on nickel foam (Pt@Ni(OH)2-NF) electrodes. We reveal that with increasing current density, changes in interfacial water structure alter the rate-determining step of the HER. Pt@Ni(OH)2-NF exhibited excellent performance in alkaline electrolytes, achieving 1000 mA cm-2 at 114 mV overpotential. This study provides a novel approach to optimizing alkaline water electrolysis dynamics by enhancing mass transfer, further paving the way for more efficient and energy-saving hydrogen production.

Unassisted self-healing photocatalysts based on Le Chatelier’s principle

Self-healing is a fundamental ability inherent in humans, plants, and other living organisms. To date, a variety of materials with self-healing properties have been developed. However, these materials usually require external inputs such as electric potentials or healing agents to initiate or promote self-healing reactions. Herein, we present a novel self-healing mechanism that operates without any external input, utilizing the dynamic equilibrium between the solid-state and dissolved materials. We employed organic–inorganic perovskites to validate our strategy. Single-particle spectroscopy and imaging demonstrated the spontaneous self-healing of perovskites after photodamage under dynamic equilibrium conditions. Furthermore, we found that perovskites can generate hydrogen in both healed and damaged states. Remarkably, the perovskites exhibited hydrogen generation over four cycles of photodamage and self-healing. The proposed concept and experimental results provide valuable insights for the development of energy conversion and storage systems with improved long-term durability.

MXene Jacketed Amorphous Ga2O3 Nanofibers Modulate the Fiber Surface-Rich Electron for Boosted Electrocatalytic Ammonia Synthesis.

Nitrogen (N2) activation and the hydrogen evolution reaction pose significant limitations on the electrocatalytic nitrogen reduction reaction (NRR) performance. The exclusive electronic structure of the main group elements has the advantage of inhibiting hydrogen generation in electrochemical NRR. However, the poor conductivity and activity remain the obstacles to its application. Herein, we report a combination strategy of cation-induced amorphous Ga2O3 nanofibers and heterostructure engineering, thereby effectively enhancing electrocatalytic performance. The amorphization of Ga2O3 nanofibers generates more oxygen vacancies that enhance the N2 activation and electron transfer ability. Additionally, by constructing heterogeneous structures to drive the charge transfer, we enrich electronics on the surface of a-Ga2O3 nanofibers and increase their catalytic activity. Thus, the a-Ga2O3/MXene nanofibers deliver the NH3 yield of 50.00 μg h-1 mg-1 and FE of 19.13% at -0.35 V. We anticipate that these findings will offer a new reference value for further ammonia synthesis research on Ga2O3 materials.

Ways to assess hydrogen production via life cycle analysis.

As global energy demand increases and reliance on fossil fuels becomes unsustainable, hydrogen presents a promising clean energy alternative due to its high energy density and potential for significant CO2 emission reductions. However, current hydrogen production methods largely depend on fossil fuels, contributing to considerable CO2 emissions and underscoring the need to transition to renewable energy sources and improved production technologies. Life Cycle Analysis (LCA) is essential for evaluating and optimizing hydrogen production by assessing environmental impacts such as Global Warming Potential (GWP), energy consumption, toxicity, and water usage. The key findings indicate that energy sources and feedstocks heavily influence the environmental impacts of hydrogen production. Hydrogen production from renewable energy sources, particularly wind, solar, and hydropower, demonstrates significantly lower environmental impacts than grid electricity and fossil fuel-based methods. Conversely, hydrogen production from grid electricity primarily derived from fossil fuels shows a high GWP. Furthermore, challenges related to data accuracy, economic analysis integration, and measuring mixed gases are discussed. Future research should focus on improving data accuracy, assessing the impact of technological advancements, and exploring new hydrogen production methods. Harmonizing assessment methodologies across different production pathways and standardizing functional units, such as "1 kg of hydrogen produced, " are critical for enabling transparent and consistent sustainability evaluations. Techniques such as stochastic modelling and Monte Carlo simulations can improve uncertainty management and enhance the reliability of LCA results.

Plasma-Assisted Hydrogen Production: Technologies, Challenges, and Future Prospects

As global demand for clean energy continues to rise, hydrogen, as an ideal energy carrier, plays a crucial role in the energy transition. Traditional hydrogen production methods predominantly rely on fossil fuels, leading to environmental pollution and energy inefficiency. In contrast, plasma-assisted hydrogen production, as an emerging technology, has gained significant attention due to its high efficiency, environmental friendliness, and flexibility. Plasma technology generates high-energy electrons or ions by exciting gas molecules, which, under specific conditions, effectively decompose water vapor or hydrocarbon gases to produce hydrogen. This review systematically summarizes the basic principles, technological routes, research progress, and potential applications of plasma-assisted hydrogen production. It focuses on various plasma-based hydrogen production methods, such as water vapor decomposition, hydrocarbon cracking, arc discharge, and microwave discharge, highlighting their advantages and challenges. Additionally, it addresses key issues facing plasma-assisted hydrogen production, including energy efficiency improvement, reactor stability, and cost optimization, and discusses the future prospects of these technologies. With ongoing advancements, plasma-assisted hydrogen production is expected to become a mainstream technology for hydrogen production, contributing to global goals of zero carbon emissions and sustainable energy development.

Energy Management of a 1 MW Photovoltaic Power-to-Electricity and Power-to-Gas for Green Hydrogen Storage Station

Green hydrogen is increasingly recognized as a sustainable energy vector, offering significant potential for the industrial sector, buildings, and sustainable transport. As countries work to establish infrastructure for hydrogen production, transport, and energy storage, they face several challenges, including high costs, infrastructure complexity, security concerns, maintenance requirements, and the need for public acceptance. To explore these challenges and their environmental impact, this study proposes a hybrid sustainable infrastructure that integrates photovoltaic solar energy for the production and storage of green hydrogen, with PEMFC fuel cells and a hybrid Power-to-Electricity (PtE) and Power-to-Gas (PtG) configurations. The proposed system architecture is governed by an innovative energy optimization and management (EMS) algorithm, allowing forecasting, control, and supervision of various PV–hydrogen–Grid transfer scenarios. Additionally, comprehensive daily and seasonal simulations were performed to evaluate power sharing, energy transfer, hydrogen production, and storage capabilities. Dynamic performance assessments were conducted under different conditions of solar radiation, temperature, and load, demonstrating the system’s adaptability. The results indicate an overall efficiency of 62%, with greenhouse gas emissions reduced to 1% and a daily production of hydrogen of around 250 kg equivalent to 8350 KWh/day.

A frontier for advancement in hydrogen generation from engineered MXenes: a mini review

A frontier for advancement in hydrogen generation from engineered MXenes: a mini review

Theoretical Understanding of LaTaON2 Decorated With Metal Cocatalysts for Photocatalytic Hydrogen Evolution Reaction

ABSTRACTLaTaON2 is a promising visible‐light‐responsive photocatalyst for water splitting because of its broad visible light absorption and suitable band edge positions. However, the high defect concentration hinders the charge transfer and results in the poor photocatalytic performance of LaTaON2. Loading proper cocatalysts is one of the most efficient strategies for promoting charge separation/transfer and achieving high reaction activity. In this work, we have used density functional theory calculations to study the depositions of Pt, Ru, and Ni single atom cocatalysts on LaTaON2(010) surface. The most stable adsorption configuration is the same site for all the elements, namely the top of the N atom on the La‐terminated surface and the fourfold hollow site on the Ta‐terminated surface. The adsorption of the metal single atom on Ta‐termination is stronger than that on La‐termination due to the formation of more bonds. Upon the deposition, no localized impurity states appear in the middle of the forbidden gap since the nd states of metal adatoms are located within the valence band and conduction band of LaTaON2. The efficiency of the photocatalysts is probed by investigating their ability to adsorb the H atom in a thermodynamically favorable manner. Our results reveal that the energetically favorable sites of HER are the N atom on the La‐termination and the O and N atoms on the Ta‐termination, respectively. Compared with the clean surface, the surfaces with Pt, Ru, and Ni single adatoms exhibit higher performance for HER because loading metal cocatalysts can further activate the surface nonmetal atoms and reduce the Gibbs free energy of hydrogen adsorption. The work gives an atom‐level insight into the role of metal single atom cocatalysts in the LaTaON2 photocatalyst for hydrogen production.

Stable Ni(II) sites in Prussian blue analogue for selective, ampere-level ethylene glycol electrooxidation

The industrial implementation of coupled electrochemical hydrogen production systems necessitates high power density and high product selectivity for economic viability and safety. However, for organic nucleophiles (e.g., methanol, urea, and amine) electrooxidation in the anode, most catalytic materials undergo unavoidable reconstruction to generate high-valent metal sites under harsh operation conditions, resulting in competition with oxygen evolution reaction. Here, we present unique Ni(II) sites in Prussian blue analogue (NiFe-sc-PBA) that serve as stable, efficient and selective active sites for ethylene glycol (EG) electrooxidation to formic acid, particularly at ampere-level current densities. Our in situ/operando characterizations demonstrate the robustness of Ni(II) sites during EG electrooxidation. Molecular dynamics simulations further illustrate that EG molecule tends to accumulate on the NiFe-sc-PBA surface, preventing hydroxyl-induced reconstruction in alkaline solutions. The stable Ni(II) sites in NiFe-sc-PBA anodes exhibit efficient and selective EG electrooxidation performance in a coupled electrochemical hydrogen production flow cell, producing high-value formic acid compared to traditional alkaline water splitting. The coupled system can continuously operate at stepwise ampere-level current densities (switchable 1.0 or 1.5 A cm−2) for over 500 hours without performance degradation.

High-efficiency photocatalytic hydrogen production with Zn-VIA (VIA=O, S, Se, Te) enhanced by lamellar Cu2MoS4 under visible light

High-efficiency photocatalytic hydrogen production with Zn-VIA (VIA=O, S, Se, Te) enhanced by lamellar Cu2MoS4 under visible light

Key Role of Bridge Adsorbed Hydrogen Intermediate on Pt-Ru Pair for Efficient Acidic Hydrogen Production.

Atop and multiple adsorbed hydrogen are considered as key intermediates on Pt-group metal for acidic hydrogen evolution reaction (HER), yet the role of bridge hydrogen intermediate (*Hbridge) is consistently overlooked experimentally. Herein, a Pt atomic chain modified fcc-Ru nanocrystal (Pt-Ru(fcc)) is developed with a co-crystalline structure, featuring *Hbridge intermediate bonded on the Pt-Ru pair site. Electrons leap from the pair site to *Hbridge facilitate hydrogen desorption, thus accelerating the Tafel kinetics and ensuring outstanding electrocatalytic performance, with a low overpotential (4.0mV at 10mA cm-2) and high turnover frequency (56.4 H2 s-1 at 50 mV). Notably, the proton exchange membrane water electrolyzer PEMWE with ultra-low loading of 10 ugPt cm-2 shows excellent activity (1.61V at 1.0 A cm-2) and low average degradation rate (4.0 µV h-1 over 1000h), significantly outperforming the benchmark Pt/C. Furthermore, the PEMWE-based 80µm Gore membrane under identical operating conditions requires only 1.54 and 1.58V to achieve 1.0 and 1.5 A cm-2. This finding highlights the key role of *Hbridge at the Pt-Ru interface in obtaining high HER intrinsic activity and underscores the transformative potential in designing next-generation bimetallic catalysts for clean hydrogen energy.

Exploring Metal- and Porphyrin-Modified TiO2-Based Photocatalysts for Efficient and Sustainable Hydrogen Production

Photocatalytic H2 production is one of the most promising approaches for sustainable energy. The literature presents a plethora of carefully designed systems aimed at harnessing solar energy and converting it into chemical energy. However, the main drawback of the reported photocatalysts is their stability. Thus, the development of a cost-effective and stable photocatalyst, suitable for real-world applications remains a challenge. An ideal photocatalyst for H2 production must possess appropriate band-edge energy positions, an effective sacrificial agent, and a suitable cocatalyst. Among the various photocatalysts studied, TiO2 stands out due to its stability, abundance, and non-toxicity. However, its efficiency in the visible spectrum is limited by its wide bandgap. Metal doping is an effective strategy to enhance electron–hole separation and improve light absorption efficiency, thereby boosting H2 synthesis. Common metal cocatalysts used as TiO2 dopants include platinum (Pt), gold (Au), copper (Cu), nickel (Ni), cobalt (Co), ruthenium (Ru), iron (Fe), and silver (Ag), as well as bimetallic combinations such as Ni-Fe, Ni-Cu, Nb-Ta, and Ni-Pt. In all cases, doped TiO2 exhibits higher H2 production performance compared to undoped TiO2, as metals provide additional reaction sites and enhance charge separation. The use of bimetallic dopants further optimizes the hydrogen evolution reaction. Additionally, porphyrins, with their strong visible light absorption and efficient electron transfer properties, have demonstrated potential in TiO2 photocatalysis. Their incorporation expands the photocatalyst’s light absorption range into the visible spectrum, enhancing H2 production efficiency. This review paper explores the principles and advancements in metal- and porphyrin-doped TiO2 photocatalysts, highlighting their potential for sustainable hydrogen production.

Bio-inspired computational intelligence metaheuristic-based optimization and sensitivity analysis approach to determine techno-economic feasibility of hydrogen refueling stations for fuel cell vehicles

This study presents a comprehensive economic and technological evaluation of renewable hybrid power systems for hydrogen refueling stations (HRS) in Nizwa, Oman, leveraging cutting-edge optimization algorithms to determine the most cost-effective and efficient hybrid energy system configurations. Three hybrid energy systems of photovoltaic-wind turbine-battery (PV-WT-B), photovoltaic-wind-fuel cell-battery (PV-WT-FC-B), and wind turbine-battery (WT-B) were evaluated based on net present cost (NPC), levelized cost of energy (LCOE), and levelized cost of hydrogen (LCOH). The study employs advanced optimization techniques, including the Mayfly Algorithm, Genetic Algorithm, CUKO Search, Gray Wolf Optimizer (GWO), Constrained Particle Swarm Optimization (CPSO), Harmony Search (HS), and Flower Pollination Algorithm to determine the most viable hybrid energy system for the HRS in Nizwa. The results indicate that CPSO consistently achieves the lowest NPC, LCOE, and LCOH, whereas HS and GWO yield higher costs due to convergence inefficiencies. Sensitivity analysis reveals a strong inverse correlation between PV capacity and cost metrics, highlighting the economic advantage of increased solar generation. Additionally, hybrid configurations integrating PV and wind turbine (PV-WT-B, PV-WT-FC-B) significantly reduce NPC compared to WT-B, reinforcing the role of solar energy in optimizing economic costs. Furthermore, fuel cell integration (PV-WT-FC-B) imposes additional economic burdens, making PV-WT-B the most viable solution for HRS deployment in Oman. More so, the annual worth and return-on-investment analysis demonstrated that the PV-WT-B is the preferred energy system to meet the needs of the HRS in terms of investment. The findings underscore the importance of renewable energy fraction and capacity factor in energy economics, demonstrating that higher PV integration enhances sustainability and cost-efficiency. This study provides a transformative framework for decarbonizing Oman’s transportation sector, offering insights into optimal hydrogen production strategies to advance the global clean energy transition.