Efficient Hydrogen Production Research Articles

Porous and defective NiCo2O4 spinel derived from bimetallic NiCo-based Prussian blue analogue for enhanced hydrogen production via the urea electro-oxidation reaction

The efficient hydrogen production via overall water splitting is seriously restrained by the slow kinetics of the oxygen evolution reaction (OER). The substantially low potential for the urea electro-oxidation reaction (UOR) can tackle this problem by replacing the OER at the electrolyzer anode. Herein, the NiCo2O4 spinel with rich oxygen vacancies (Ov) and embedded within mesoporous carbon network (Ov-NiCo2O4@mC) was derived from NiCo-based Prussian blue analogous (NiCo PBA) and exploited as the bifunctional electrocatalyst of the UOR and OER for boost the hydrogen production via the overall water splitting. Benefiting to the regular skeleton and abundant dual metal sites of NiCo PBA, the derived Ov-NiCo2O4@mC comprises abundant oxygen vacancies, lattice defects, and adjustable electron structure. These features afford Ov-NiCo2O4@mC the improved UOR ability, showing the potential of 1.33 V versus reversible hydrogen electrode (RHE) at the current density of 10 mA cm−2, along with a small Tafel slopes of 31 mV dec-1, remarkably lower than that of the OER (1.51 V versus RHE, Tafel slope = 85 mV dec-1). The UOR performance of Ov-NiCo2O4@mC substantially outperforms to most of the reported Co and/or Ni-based electrocatalysts. Impressively, the assembled two-electrode urea-assisted overall water splitting device shows the small voltage for the hydrogen production (1.43 V versus RHE) and good long-term stability. The present work can provide a new alternative for the efficient hydrogen production using the MOFs-derivatives.

Au/Ag@ZnS yolk-shell photocatalysts enhanced with noble metals and hyaluronic acid for efficient hydrogen production in rheumatoid arthritis therapy

Rheumatoid arthritis, characterized by the abnormal proliferation of synovial cells and extensive macrophage infiltration, is a chronic inflammatory disease. Molecular hydrogen, known for its antioxidant properties, has shown promise in eliminating reactive oxygen species. However, the low solubility and bioavailability of hydrogen limit the effectiveness of this therapy. To overcome these issues, we developed a novel yolk-shell heterostructure, H-AAZS (Au/Ag@ZnS modified hyaluronic acid), utilizing a hydrothermal cation exchange process. Through ion doping, semiconductor hybridization, and Schottky barriers in H-AAZS, photocatalysis for hydrogen generation has been successfully implemented using 660 nm laser irradiation. Additionally, the H-AAZS demonstrate the capacity for mild photothermal therapy, inducing apoptosis in synovial cells with Au's hot electrons with 660 nm laser irradiation. This strategy not only improves the abnormal proliferation of synovial cells but also avoids the exacerbation of inflammation caused by thermal stimulation. Both in vitro and in vivo experiments validate the synergistic effects of hydrogen production mediated anti-inflammatory responses, macrophage polarization and photothermal therapy. Therefore, this work represents a significant advancement as it ingeniously harnesses photocatalysis to modulate the synovial microenvironment while mitigating the side effects associated with photothermal therapy. This nanocrystal provides new and valuable insights into the potential treatment of Rheumatoid arthritis.

Carbon nanomaterials for efficient oxygen and hydrogen evolution reactions in water splitting: A review

Water splitting has gained significant attention as a means to produce clean and sustainable hydrogen fuel through the electrochemical or photoelectrochemical decomposition of water. Efficient and cost-effective water splitting requires the development of highly active and stable catalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Carbon nanomaterials, including carbon nanotubes, graphene, and carbon nanofibers, etc., have emerged as promising candidates for catalyzing these reactions due to their unique properties, such as high surface area, excellent electrical conductivity, and chemical stability. This review article provides an overview of recent advancements in the utilization of carbon nanomaterials as catalysts or catalyst supports for the OER and HER in water splitting. It discusses various strategies employed to enhance the catalytic activity and stability of carbon nanomaterials, such as surface functionalization, hybridization with other active materials, and optimization of nanostructure and morphology. The influence of carbon nanomaterial properties, such as defect density, doping, and surface chemistry, on electrochemical performance is also explored. Furthermore, the article highlights the challenges and opportunities in the field, including scalability, long-term stability, and integration of carbon nanomaterials into practical water splitting devices. Overall, carbon nanomaterials show great potential for advancing the field of water splitting and enabling the realization of efficient and sustainable hydrogen production.

Experimental investigation on the electrical and hydrogen-production performance of a novel PEM electrolyzer driven by CdTe PV with a tracking system

Addressing the challenges of intermittent and variable energy supply, solar hydrogen production via electrolysis has garnered significant attention due to its unique advantages, emerging as a hot topic in the scientific research domain. However, the application of this technology is currently mainly related to the non-tracking system, which undergoes a rapid change in solar irradiation during the day. To expand the matching relationship of solar irradiation, PV characteristics, and electrolyzer, this paper proposes the development of a Proton Exchange Membrane (PEM) electrolyzer driven by Cadmium Telluride (CdTe) photovoltaic (PV) modules with a tracking system for hydrogen production. An experimental platform was set up in Chengdu and the performance tests were carried out for different operating modes during summer. The experimental results demonstrate that the average electrical and hydrogen production efficiencies of the system are 13.11% and 7.88%, respectively, on a sunny day, with a total of 566.7 L of hydrogen produced within 7 h of operation. Furthermore, the solar irradiation received by the tracking surface of the system is significantly enhanced by 10.29% in comparison to the horizontal surface. On a cloudy day with an electrolyzer inlet water temperature of 45 °C, the system has the potential to achieve a hydrogen production efficiency of 11.15 %. At a constant current density of 1.0 A/cm2, the efficiency of the electrolysis process increased by 2.07% and 1.25% for each 10 °C increase in the temperature of the electrolyzer, having an inlet temperature of 35 °C. This study offers a novel approach for a PV-PEM system with a higher hydrogen production efficiency while also establishing a robust foundation for technology optimization and broader implementation.

Boosted photothermal-assisted photocatalytic H2 production by dual heat source-based S-scheme heterojunction

With advances in catalytic research, improvement of catalytic efficiency by using photothermal synergies to strengthen the reaction mechanisms has been focused. In this work, a novel photothermal-assisted photocatalytic H2 production system was constructed by loading Co3O4 nanoparticles on surface of black carbon nitride (BCN) nanosheets, served as the dual thermal source to enhance photothermal effect for synergistically assisting in photocatalytic H2 evolution with optimal H2 production rate reached 3.7 mmol g−1 h−1, significantly higher than that of pure carbon nitride (CN) and BCN. Moreover, the S-scheme heterojunction is also formed between Co3O4 and BCN, leading to the optimization of the charge transfer path, which further promotes the improvement of photothermal-assisted photocatalytic H2 production activity. This study provides the design idea of coupling the multi-heat source effect with the heterojunction electron transport for constructing an efficient photothermal-assisted hydrogen production system.

Enhancing Photocatalytic Hydrogen Production Efficiency with Carbon Fibers: A Mini Review

Enhancing Photocatalytic Hydrogen Production Efficiency with Carbon Fibers: A Mini Review

High Performance of Mn2O3 Electrodes for Hydrogen Evolution Using Natural Bischofite Salt from Atacama Desert: A Novel Application for Solar Saline Water Splitting.

Solar saline water splitting is a promising approach to sustainable hydrogen production, harnessing abundant solar energy and the availability of brine resources, especially in the Atacama Desert. Bischofite salt (MgCl2·6H2O) has garnered significant attention due to its wide range of industrial applications. Efficient hydrogen production in arid or hyper arid locations using bischofite solutions is a novel and revolutionary idea. This work studied the electrochemical performance of Mn2O3 electrodes using a superposition model based on mixed potential theory and evaluated the superficial performance of this electrode in contact with a 0.5 M bischofite salt solution focusing on the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) that occur during saline water splitting. The application of the non-linear superposition model provides valuable electrochemical kinetic parameters that complement the understanding of Mn2O3, this being one of the novelties of this work.

New hybrid system of PV/T, solar collectors, PEM electrolyzer, and HDH for hydrogen and freshwater production: Seasonal performance investigation

A new hybrid energy system of PV/T, flat plate collector, PEM electrolyzer, and humidification-dehumidification desalination is introduced here. A comprehensive mathematical model for the system seasonal performance is constructed and solved numerically using MATLAB software. A year-round comparison between the traditional PV/T performance and its concentrated counterpart indicates that the latter performs better compared to power, hydrogen, and freshwater production and system overall efficiency. The maximum monthly achieved PV/T efficiency, electrolyzer efficiency, desalination system Gain Output Ratio, and overall system efficiency are 52 %, 62 %, 4.8 %, and 44 %, respectively at a concentration ratio of 4 and maximum allowable PV temperature. The system produces 82,200 kWh of energy annually and provides 77,700 kWh and 1500 kWh to the electrolyzer and the electric heater, respectively. Moreover, the system produces an annual freshwater production of about 52,700 kg, out of which approximately 10,000 kg are consumed in the electrolysis process, and an annual hydrogen production of approximately 1120 kg.

Synthesis of concave Au NRs-Pt-CdS plasmonic photocatalyst with efficient hydrogen production rate

Light-driven water photolysis for hydrogen (H2) generation has been proven to be exceptionally efficient in the field of energy transformation. Nevertheless, the practical applications of many single-component semiconductors still suffer from a relatively low energy conversion efficiency. In this work, concave gold nanorods (Au NRs) with three plasmon resonance modes were synthesized using a one-step method in an aqueous solution. Pt nanoparticles and CdS nanocrystals were rational grown onto Au NRs to design the plasmonic photocatalysts with specific morphology and structure characteristic. Photocatalytic test indicated that concave Au NRs-Pt-CdS hetero-nanostructure possess efficient H2 production rate under visible and near-infrared regions. These findings offer a blueprint for creating a novel group of hetero-nanostructures that combine faceted noble metal nanoparticles with semiconductor materials, demonstrating promise for applications across fields such as photocatalysis and energy storage.

Immobilization of Metal Nanoparticles to an Ultrathin Two-Dimensional Conjugated Metal-Organic Framework for Synergistic Electrocatalysis.

Metal-organic frameworks (MOFs) have been considered as promising hosts for immobilizing ultrafine metal nanoparticles (MNPs) due to their high surface area and porosity. However, electrochemical applications of such emerging composites are severely limited by the poor electrical conductivity and large size of the MOFs. Herein, we report the general synthesis of incorporating various MNPs into a conjugated MOF ultrathin nanosheet (Cu-TCPP UNS) matrix, which not only prevents agglomeration and restricts the growth of MNPs but also benefits the exposure of active sites and the transport of electrons. Specifically, the obtained PtCu@Cu-TCPP UNSs exhibited nearly two times higher mass activity for the methanol oxidation reaction (MOR) than the commercial Pt/C catalyst. Mechanistic studies reveal that the strong interaction between MNPs and Cu-TCPP promotes the oxidation of the CO intermediate. Moreover, the PtCu@Cu-TCPP UNSs can be employed as bifunctional electrocatalysts to couple MOR with the hydrogen evolution reaction for highly efficient hydrogen production.

Simple solution immersion for realizing bifunctional catalyzation of water splitting in various electrolytes

Developing cost-effective, highly efficient and scalable bifunctional electrocatalysts for hydrogen production is crucial for advancing hydrogen energy systems. However, current methods are hindered by high energy consumption and material limitations. This work introduces a bifunctional electrocatalyst (NiFe-OH@Co2P@NF), by simply immersing a hierarchical cobalt phosphide electrode in mixed Ni/Fe solution, followed by forming layered nickel-iron hydroxides on the surface. Electrochemical tests reveal that this catalyst enhances active site exposure, accelerates electron transfer, and significantly lowers the overpotential for water electrolysis. It requires minimal overpotentials (79 mV at 10 mA cm−2, 175 mV at 150 mA cm−2) in 1 M KOH solution. In a dual-electrode electrolytic cell system, the catalyst enables efficient hydrogen production at a current density of 10 mA cm−2 with just 1.52 V, demonstrating robust stability during prolonged alkaline water splitting tests. Moreover, the bifunctional electrodes display good performance and durability in simulated alkaline seawater and 1 M KOH + seawater.

Efficient photocatalytic hydrogen production via single-atom Pt anchored hydrogen-bonded organic frameworks

Constructing single-atom catalysts (SACs) using organic porous framework materials as supports presents a promising approach for developing highly efficient photocatalysts for hydrogen evolution. However, the fabrication of SACs that are both highly stable and active poses a significant challenge, particularly in the precise anchoring of metal single atoms. In this study, we utilized 1,3,6,8-tetra (p-methyl benzoate) pyrene as a ligand to synthesize pyrene-based hydrogen-bonded organic frameworks (denoted as PFC-1) through a self-assembly approach. Subsequently, a liquid-phase photoreduction process was employed to deposit noble metal platinum (Pt) onto PFC-1, resulting in the fabrication of SACs (PFC-1@Pt). Characterization results confirmed that Pt existed in a monatomic state, anchored through PtC and PtO coordination bonds with PFC-1. Serving as electron capture and separation centers, the Pt single atoms effectively suppressed electron-hole recombination, thereby prolonging carrier lifetimes. Consequently, the PFC-1@Pt SAC exhibited efficient hydrogen evolution performance with a rate of 2202.5 μmol g−1 h−1 and maintained photocatalytic activity for over 40 h. Our findings provide a systematic approach for developing efficient and stable SACs based on HOFs, expanding the potential applications of HOF materials in photocatalysis.

Photocatalytic seawater splitting by Earth-abundant catalysts: metal-semiconductor metamaterials made of plasmonic magnesium diboride and transitional metal dichalcogenides.

Metal-semiconductor metamaterials hold great promise for photocatalytic water splitting due to their excellent light harvesting in a broad spectral range as well as efficient charge carrier generation and transfer. In majority of such metamaterials, semiconductors are used to initiate the water splitting reaction, while their metal counterparts are employed to improve light harvesting through plasmonic effects. Here, we describe for the first time an exceptional reversed case of metal-semiconductor photocatalysts in which metals are used to initiate the water splitting reaction and semiconductors are employed to improve light harvesting through blackbody effect and serve as co-catalysts. The studied photoanodes are made of non-noble plasmonic MgB2 combined with transition metal dichalcogenides (TMDCs). The plasmonic resonances of the MgB2 component contribute to field confinement, plasmon-exciton coupling, and hot-electron transfer providing an enhancement of photoactivity in the entire solar spectrum capable of water splitting. The TMDC component provides impedance matching and enhances light absorption by the metal catalyst. We demonstrate seawater splitting with MgB2-TMDCs photoanodes attaining current densities of ~ 3 mA⋅cm-2 at solar radiation. The overall efficiency of hydrogen production in seawater splitting by sunlight with the help of the studied photoanodes is 3% at bias voltage of Vbias = 0.3 V.

Integrating solar-powered branched GAX cycle and claude cycle for producing liquid hydrogen: Comprehensive study using real data and optimization

The present study introduces a novel hydrogen liquefaction system that integrates a Claude cycle and a branched GAX cycle, marking the first instance of such a combination. Utilizing solar energy improves hydrogen manufacturing efficiency and sustainability. This research uses actual data to estimate the best operating time by examining thermodynamic performance, payback duration, exergoeconomic parameters, environmental effect, and sustainability. A current bi-objective optimization technique maximizes exergy efficiency and minimizes hydrogen liquefaction cost. Evaporator and generator temperatures, solar direct beam irradiation, and cycle's high pressure are key decision variables. The sensitivity analysis highlights the substantial influence of cycle's high pressure on hydrogen liquefaction cost, as indicated by a sensitivity index of 0.486. The research calculates the best solution using TOPSIS decision-making, resulting in 50.22 % exergy efficiency and $1.366/kg hydrogen liquefaction cost. After conducting a thorough case study, it becomes evident that May is the most optimal month for liquid hydrogen production, payback period, and net profit. However, January has a high coefficient of performance and exergy efficiency and low liquid hydrogen production cost. The cheapest capital investment month is July. This complete study of the solar-driven hydrogen liquefaction system uncovers critical parameters and their effects, enabling hydrogen production efficiency and sustainability.

Full-spectrum solar water decomposition for hydrogen production via a concentrating photovoltaic-thermal power generator-solid oxide electrolysis cell system

This study introduces a novel solar-powered concentrating photovoltaic-thermal power generator-solid oxide electrolysis cell system designed to enhance hydrogen production efficiency by optimizing both electrical and thermal energy utilization. The system incorporates a thermal power generator to convert excess high-temperature thermal energy into electrical energy, addressing energy losses associated with high-temperature water electrolysis. Thermodynamic analysis shows that the integration of the thermal power generator improves energy and exergy efficiencies to 0.60 and 0.52, while lowering the optimal operating temperature to 1173 K. The system’s efficiency is sensitive to the proportion of electrical energy supplied by the thermal power generator, with an optimal range identified between 0.1 and 0.2. Higher temperatures improve hydrogen production and efficiency, but increased voltage negatively impacts thermodynamic efficiency. These findings demonstrate that the proposed system offers substantial improvements over conventional solar hydrogen production methods, making it a promising candidate for sustainable hydrogen production. Further research will focus on system integration, material costs, and scalability for commercial use.

Efficient hydrogen production from food waste leachate using single-chamber microbial electrolysis cell

The aim of this study was to develop an efficient strategy for enhancing H2 production in the single-chamber microbial electrolysis cell (MEC) using food waste leachate as a substrate. Different pH (8.5, 9.5, 10.5, and 11.2), applied voltage (0.8, 1.2, 1.5, 1.8, 2.0, 2.2, 2.3, and 2.4 V) and negative pressure control (−50 kPa) were tested in the single-chamber MEC. Suitable pH adjustment could greatly promote electricity generation and H2 production rather than negative pressure control. Under pH of 11.5 and 2.4 V, the maximum current density reached 121.9 ± 10.9 A/m³ with an average H2 concentration of 91.9 ± 3.2% in a 1.2-L single-chamber MEC within 30 continuous cycles of operation (∼607 h), which was constructed with carbon brushes as the anode and stainless steel brushes as the cathode. The maximum H2 production rate reached 853.2 ± 70.3 L/m³•d with an H2 yield of 26.3 mmol•H2/g•COD. The COD removal of 68.3 ± 6.8% and three-dimensional excitation-emission matrix spectra of the effluent in the MEC within 21 ± 3h indicated efficient organics degradation in the leachate. Our results should provide a promising way to enhance the H2 production of MEC during leachate treatment.

Thermal and Sono-Aqueous Reforming of Alcohols for Sustainable Hydrogen Production.

Hydrogen is a clean-burning fuel with water as its only by-product, yet its widespread adoption is hampered by logistical challenges. Liquid organic hydrogen carriers, such as alcohols from sustainable sources, can be converted to hydrogen through aqueous-phase reforming (APR), a promising technology that bypasses the energy-intensive vaporization of feedstocks. However, the hydrothermal conditions of APR pose significant challenges to catalyst stability, which is crucial for its industrial deployment. This review focuses on the stability of catalysts in APR, particularly in sustaining hydrogen production over extended durations or multiple reaction cycles. Additionally, we explore the potential of ultrasound-assisted APR, where sonolysis enables hydrogen production without external heating. Although the technological readiness of ultrasound-assisted or -induced APR currently trails behind thermal APR, the development of catalysts optimized for ultrasound use may unlock new possibilities in the efficient hydrogen production from alcohols.

Seawater Electrolysis: Challenges, Recent Advances, and Future Perspectives

AbstractDriven by the advantages of hydrogen energy, such as environmental protection and high energy density, the market has an urgent demand for hydrogen energy. Currently, the primary methods for hydrogen production mainly include hydrogen generation from fossil fuels, industrial by‐products, and water electrolysis. Seawater electrolysis for hydrogen production, due to its advantages of cleanliness, environmental protection, and ease of integration with renewable energy sources, is considered the most promising method for hydrogen production. However, seawater electrolysis faces challenges such as the reduction of hydrogen production efficiency due to impurities in seawater, as well as high costs associated with system construction and operation. Therefore, it is particularly necessary to summarize optimization strategies for seawater electrolysis for hydrogen production to promote the development of this field. In this review, the current situation of hydrogen production by seawater electrolysis is first reviewed. Subsequently, the challenges faced by seawater electrolysis for hydrogen production are categorized and summarized, and solutions to these challenges are discussed in detail. Following this, an overview of an in situ large‐scale direct electrolysis hydrogen production system at sea is presented. Last but not least, suggestions and prospects for the development of seawater electrolysis for hydrogen production are provided.

Photocatalytic Ammonia Decomposition Using Dye-Encapsulated Single-Walled Carbon Nanotubes

The photocatalytic decomposition of ammonia to produce N2 and H2 was achieved using single-walled carbon nanotube (SWCNT) nanohybrids. The physical modification of ferrocene-dye-encapsulated CNTs by amphiphilic C60-dendron yielded nanohybrids with a dye/CNT/C60 coaxial heterojunction. Upon irradiation with visible light, an aqueous solution of NH3 and dye@CNT/C60-dendron nanohybrids produced both N2 and H2 in a stoichiometric ratio of 1/3. The action spectra of this reaction clearly demonstrated that the encapsulated dye acted as the photosensitizer, exhibiting an apparent quantum yield (AQY) of 0.22% at 510 nm (the λmax of the dye). This study reports the first example of dye-sensitized ammonia decomposition and provides a new avenue for developing efficient and sustainable photocatalytic hydrogen production systems.

Dahlia ball shape bimetallic phosphide-tungsten phosphide composite for anion-exchange membrane water electrolysis

Revolutionizing Water Splitting: Introducing a Breakthrough Single Heterostructure Catalyst for Highly Efficient Hydrogen and Oxygen Evolution Reactions. In this study, we present an innovative method for water splitting that introduces a remarkable single heterostructure catalyst capable of efficiently catalyzing both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Our research utilizes a highly effective hydrothermal synthesis technique to create a unique nanosphere composed of iron cobalt phosphide and tungsten phosphide (FCPWP). This FCPWP nanosphere exhibits finely tuned electronic structures and incorporates multiple active sites, resulting in significantly reduced overpotentials. When operating at current densities of 50 and 100 mA cm−2, the HER overpotentials are as low as 220 mV and 280 mV, respectively, while the OER overpotentials are only 270 mV and 350 mV. By employing the FCPWP nanosphere in a two-electrode electrolyzer configuration, we achieve exceptional results with minimal power requirements. At an operating current density of 10 mA cm−2, the electrolyzer functions at an impressively low voltage of 1.44 V, and at 1.85 V, it attains a high current density of 425 mA cm−2, showcasing an outstanding cell efficiency of 71.63% in an anion exchange membrane electrolyzer. These experimental findings are further supported by computational study. The FCPWP nanosphere emerges as an extraordinary electrocatalyst with dual-functionality for water splitting, offering great promise in the efficient production of hydrogen through electrochemical means. Our research not only introduces a fresh perspective but also paves the way for significant advancements in renewable energy technologies.