Hydrogen Energy Applications Research Articles

Abundant Surface Defects in Cobalt Hydroxides/Oxyhydroxides Induced by Zinc Species Facilitate Water Oxidation.

The complex process of the anodic oxygen evolution reaction (OER) severely hinders overall water splitting, which further limits the large-scale production and application of hydrogen energy. In this work, one type of bimetallic coordination polymer of ZnCoBTC using the MOF-on-MOF strategy has been synthesized where both Co(II) and Zn(II) cations exhibit the same coordination environment. By applying an electric potential, the predesigned bimetallic MOF precursor can be conveniently degraded into CoOxHy as an active species for efficient OER. Owing to the dissolution of ZnOxHy species, in situ formed disordered defects on the external surface of the catalyst increase the specific surface area as well as expose abundant active materials. Therefore, the ZnCoOxHy nanosheet shows excellent OER performance and reaches an overpotential of only 334 mV at 10 mA cm-2 with a Tafel slope of 66.4 mV dec-1, indicating fast reaction kinetics. The results demonstrate that metals with the same coordination environment can undergo in situ replacement or secondary growth on the pristine MOF, and they can be electrochemically degraded into highly efficient catalysts for future energy applications.

Stable and 7.7 wt% hydrogen storage capacity of Ti decorated Irida-Graphene from first-principles calculations

Solid-state hydrogen storage is crucial for the widespread applications of hydrogen energy. It is a grand challenge to find appropriate materials that provide high hydrogen density and ambient temperature stability. Herein, we investigated the potential of Ti-decorated Irida-Graphene, a promising effective hydrogen storage system, as a novel hydrogen storage material using first-principles calculation. Irida-Graphene is a two-dimensional isomer of carbon consisting of tri-, hexa-, and octagon rings of carbon. Ti atoms are tightly bounded to the hexagonal rings. Binding energy analysis reveals that a single Ti atom in the primitive unit-cell of Ti-decorated Irida-Graphene is capable to bind up with 5H2 molecules and the average adsorption energy was −0.41 eV/H2. It indicates the gravimetric density of 7.7 wt%. The stability is attributed to Kubas-type interactions and ensured by a 5.0 eV diffusion energy barrier that prevents the Ti–Ti clustering. Further, ab initio molecular dynamics simulations results illustrate that the system remains stable at 600 K, higher than the desorption temperature of 524 K, implying the stability of the system during hydrogen recharge and discharge. The exceptional hydrogen storage performance suggests that Ti-decorated Irida-Graphene is an outstanding candidate for hydrogen storage materials.

Quantitative risk assessment of China's first liquid hydrogen refueling station.

Hydrogen refueling stations (HRSs) are among the most important infrastructures for fuel cell vehicles. However, the safety issue of HRSs has become a key constraint to the wide application and development of hydrogen energy. This article presents a quantitative risk assessment of the first liquid HRS (LHRS) in China and conducts a comprehensive assessment in terms of both individual (IR) and societal risks (SRs). The results showed that both the IRs and SRs related to the LHRS exceeded the risk acceptance criteria. The rupture of the flexible hose of the dispenser and the leak from the compressor are the main contributors to these risks. On the other hand, implementing appropriate mitigation measures on the level of the LHRS dispenser and compressor, including the addition of breakaway couplings in the flexible hose of the dispenser, the installation of hydrogen detection sensors, the arrangement of automatic and manual emergency shutdown buttons, and the elevation of the compressor, is capable of reducing the risk of the LHRS to be within the risk acceptance criteria.

Probing the catalytic activity of first-row transition metal doped C20 fullerene as remarkable HER electrocatalysts: A DFT study

Hydrogen evolution reaction (HER) has captivated the interest of researchers due to ever increasing demand for future sources of energy. With the advancement in renewable energy resources, electrocatalytic production of hydrogen has been considered as the most suitable way for hydrogen production for fuel cells and combustion engines. Herein, we studied HER activity of transition metal doped C20 fullerene (M@C20) by means of adsorption energy, Gibbs free energy and electronic density calculations. Ni@C20 and Cu@C20 complexes provide the best HER activity with Gibbs free energy of −0.09 eV for each. Furthermore, electronic properties such as the density of states (DOS) and frontier molecular orbital analyses are performed which indicate that transition metal doping significantly alters the electronic properties of studied M@C20 complexes. Whereas the adsorption of hydrogen does not affect the electronic parameters much. The basic understanding of hydrogen adsorption mechanism together with analyses of electronic parameters is crucial for the synthesis of highly efficient electrocatalysts for hydrogen energy applications. The critical findings of this study declares that both Ni@C20 and Cu@C20 complexes can act as promising electrocatalysts for hydrogen evolution reaction with low overpotential.

Ultrasmall RuM (Mo, W, Cr) Decorated on Nitrogen-doped Carbon Nanosheet with Strong Metal-support Interactions for Electrocatalytic Hydrogen Generation in Wide pH Range

Developing efficient electrocatalysts for hydrogen evolution reaction (HER) in full pH range can promote the practical applications of hydrogen energy. In this work, nitrogen doped carbon nanosheets supported RuM (Mo, W, Cr) (RuM/NCN) are prepared through an ultrafast microwave approach. The carbon nanosheet structure coupled with the ultrasmall RuM nanoparticles can expose rich active sites to optimize the catalytic activity. Moreover, the strong metal-support interactions also favor to accelerate the reactions kinetics and improve stability. Thus, the developed RuMo/NCN (RuW/NCN) show excellent HER catalytic activities with overpotentials of 72 (75) mV, 82 (82) mV and 124 (119) mV to reach current density of 10 mA cm -2 in 1 M KOH, 0.5 M H2SO4 and alkaline seawater, respectively, and also achieve excellent performance in 1 M PBS. This work provides a valid and novel avenue to design efficient electrocatalysts in renewable energy-related fields.

Electrolytic Hydrogen Evolution Study of Porous Tungsten Carbide‐Loaded Pt Derived from ZIFs

AbstractThe development of an electrochemical hydrogen evolution catalyst with high activity and low Pt loading and excellent stability is of high significance for the extensive promotion and practical application of hydrogen energy. Hence, we introduced ZIFs and their derivatives with tunable pore size and large specific surface area, which were carbonized at high temperatures and supported with Pt as catalysts for hydrogen evolution reaction. We used ZIF‐8 as the seed to obtain the precursor Co@ZIFs, W element was introduced into Co@ZIFs by impregnation method to synthesize WC. A series of Pt/WC catalysts were prepared with WC as support. The best sample Pt/WC‐3 in 0.5 M H2SO4 with a Pt content of 8.3 wt % has a low overpotential (η10=28 mV), which is much less than the 34 mV of 20% commercial Pt/C and had a Tafel slope of only 18.9 mV dec−1. It is noteworthy that at 8.3% Pt/WC after 40,000 s of continuous operation at 10 mA cm−2, the overpotential of Pt/WC‐3 barely rises by 5%, which indicates its excellent durability.

An effective strategy to boost hydrogen separation performance through stable mixed proton‐electron conducting membrane

AbstractHydrogen separation and purification are key to widespread application of hydrogen energy. Hydrogen permeable membranes based on lanthanum tungstate (LWO) attract attention due to favorable mechanical strength and chemical stability. However, industrial application of LWO‐based membranes has remained challenging because of modest hydrogen permeances. Here we report a novel graded porous supported symmetric (GPSS) LWO‐based membrane with improved transport properties, gas exchange dynamics, and operational stability, boosting stable hydrogen flux by several times over previously reported state‐of‐the‐art membranes.

Advanced Hybrid Ceramics for Nuclear and Hydrogen Energy Applications

AbstractGlobal energy crisis has encouraged the need for sustainable energy resources, which is the viable alternate of providing effective energy operations and considered as remedy for the ongoing energy crisis. Development in the science and technology eases out plenty of issues that were once thought to be uphill. Presently, earth is being subjected to several grave issues which need to be addressed as soon as possible. Nuclear and hydrogen energy are the important areas which promise the optimistic way of handling the existential energy crisis due to cost, scarcity of resources and unavailability of considerable feedstock. Ceramics are the diverse inorganic materials which offer tremendous chemical and physical characteristics. Due to their structural, compositional and morphological versatility, advanced ceramics based hybrid materials can be exploited in nuclear and hydrogen energy applications as discussed in this review. Extensive survey outlined the applicability of ceramics in various nuclear science based applications as they include fissionable species and possess higher thermal conductivity, their enormous resistance towards radiation and refractoriness in fuels and in waste residuals due to their potential to hold radio nuclides and surveyed the scope of several metal oxides ceramics in carrying out hydrogen energy operations via overall water splitting.

The Current Status of Hydrogen Energy Industry and Application of Hydrogen Fuel Cell Vehicles

At present, traditional fossil fuels like coal, oil, and natural gas are the main sources of the world's energy supply. With economic development and the expansion of the world population, traditional fossil energy sources are getting depleted and environmental pollution is becoming more and more serious, so it is important to find new and alternative clean energy sources to ensure energy security, enhance the natural environment and encourage the modernization and transformation of the energy infrastructure. Hydrogen energy is a type of clean energy with attributes like being clean, highly efficient, having a flexible application form, having a wide range of application scenarios, etc. One of the most important sources of sustainable energy is hydrogen. The transportation sector is a significant user of gasoline on the global energy market. Hydrogen has the potential to be a viable fuel for eco-friendly transportation since it provides energy that is reliable, safe, practical, easy to use, and competitively priced. Meanwhile, as hydrogen-powered vehicles advance quickly, there is an urgent need to improve the construction of hydrogen infrastructure for transportation in order to accommodate the wide application of hydrogen energy in transportation in the future.

Environmental Friendliness And Availability of Hydrogen Transportation and Future Improvements

As civilization develops, so does society's reliance on the earth's resources. New forms of energy are being created in order to limit the usage of nonrenewable resources. The utilization of new, clean energy sources decreases not just reliance on nonrenewable resources, but also pollutant emissions. Hydrogen is a sustainable and environmentally friendly energy source. Hydrogen transport is one of the most important applications of hydrogen energy in civilization. This research compares the differences in energy usage and emissions between hydrogen and traditional transportation. It also exhibits the economic benefits of hydrogen transportation and the adoption of hydrogen transportation in many nations. The current problems of hydrogen transport are analyzed and suggestions for improvement are given. The significance of this paper is to demonstrate the characteristics of hydrogen transport itself and to improve and popularise the use of hydrogen transport in the context of real-life situations.

First-principles prediction of enhanced hydrogen sensing performance of Pt–MoS2 monolayer upon pre-adsorption of oxygen gas

Developing hydrogen sensors with high sensitivity and selectivity is particularly critical for applications of hydrogen energy. In this work, the sensing mechanisms of Pt-doped and O2-pre-adsorbed MoS2 monolayer toward hydrogen gas are investigated by first-principles. The results of adsorption energies, adsorption distance, band gaps change and Mulliken charge suggest that the doping of Pt in MoS2 leads to more stable configuration and better sensitivity for hydrogen adsorption, and this performance is further improved with pre-adsorption of oxygen molecule on MoS2. The strong hybridization indicates the strong interaction and chemisorption between the constructed oxygen and Pt–MoS2. The sensing mechanism of Pt–MoS2 is also revealed by the energy profile for dissociation of O2 and H2 molecules on Pt–MoS2, the reaction process increases the charge carrier concentration and conductivity of the sensing material. The proposed numerical framework provides a perspective foundation for developing high-performance and complicate gas sensor.

Parametric Study on Fin Structure and Injection Tube in Metal Hydride Tank Packed with LaNi5 Alloy for Efficient and Safe Hydrogen Storage

Efficient hydrogen storage methods are crucial for the large-scale application of hydrogen energy. This work studied the effects of fin structure and injection tube on the system performance of a hydrogen storage tank packed with LaNi5 alloy. An axisymmetric finite element model of the metal hydride hydrogen storage tank was established. The fin structure and injection tube were added to the hydrogen storage tank, and the effects of the fin location and injection tube on the efficiency and safety of the hydrogen storage tank during hydriding were analyzed. A parametric study on the wall fin structure and injection tube has been carried out to optimize the design of a hydrogen storage tank, and to improve its efficiency and safety. The hydrogen storage capacity of the optimized tank packed with LaNi5 alloy can reach 1.312 wt%, which is 99% of its maximum capacity, at around 650 s. The results show that the fin structure can improve the heat transfer performance of the storage tank, and that the injection tube can enhance the mass transfer of hydrogen in the tank.

Technical and economic analysis of a pilot-scale hydrogen system: From production to application

The uneven distribution of renewable energy resources and different levels of development have produced a large amount of abandoned electricity. Hydrogen production from the electrolysis of water can effectively consume abandoned electricity. And hydrogen energy has been hailed as the ultimate energy source in the 21st century. However, the many branches of the industry have made the overall layout of local hydrogen energy a tricky issue. Therefore, combining the characteristics and development status, and pilot project data, this article selects three typical hydrogen energy industry routes with high development potential for focused study. These three routes cover the main hydrogen production, storage and transportation technologies, and hydrogen energy application scenarios. A modeling-based approach is applied to calculate the energy utilization and economics of each route. The analysis is then combined with the current development status to obtain the advantages and disadvantages, suitable conditions, and development potential of each route. Among the three routes, the PEMFC route has the highest energy efficiency of 46.6% but is less economical. Suitable for construction in and around power plants to improve energy utilization. The hydrogen transportation route has a lower energy utilization rate of 34.9%. However, this route is more economical, with a conservative estimate of hydrogen refueling cost of about 60 RMB/kg at the current demonstration level. Suitable for medium and large cities with mature hydrogen energy development. The transportation cost of pipeline hydrogen transportation is low, but the preliminary pipeline construction and modification are more complicated. Based on the research results and local conditions, the government or enterprises can personalize the design of the hydrogen energy industry chain faster and more effectively.

High-performance amorphous carbon films on titanium foils: Toward industrial preparation of coated metallic bipolar plates for proton exchange membrane fuel cells

The proton exchange membrane fuel cells (PEMFCs) composed of amorphous carbon (a-C) film surface modified metal bipolar plates (BPP) have been widely used as a new generation power source for hydrogen energy applications. However, one of the main challenges limiting the industrial deployment of a-C coated BPP remains the low deposition rate. In this study, arc ion plating with a deposition rate exceeding 100 nm/min was used to rapidly deposit a-C films with excellent performance on the surface of titanium foil (TA1). The experimental results show that the ICR of a-C coated TA1 decreases to 1.125 mΩ cm2 at a pressure of 1.4 MPa and the corrosion current density is about 3.37 × 10−9 A cm−2. In addition, industrially useable BPPs with large-sized coated a-C films has been successfully deposited. This work provides valuable reference for the industrial preparation of low-cost a-C film coating metal BPP for PEMFCs.

Key Technologies of Pure Hydrogen and Hydrogen-Mixed Natural Gas Pipeline Transportation.

Thanks to the advantages of cleanliness, high efficiency, extensive sources, and renewable energy, hydrogen energy has gradually become the focus of energy development in the world's major economies. At present, the natural gas transportation pipeline network is relatively complete, while hydrogen transportation technology faces many challenges, such as the lack of technical specifications, high safety risks, and high investment costs, which are the key factors that hinder the development of hydrogen pipeline transportation. This paper provides a comprehensive overview and summary of the current status and development prospects of pure hydrogen and hydrogen-mixed natural gas pipeline transportation. Analysts believe that basic studies and case studies for hydrogen infrastructure transformation and system optimization have received extensive attention, and related technical studies are mainly focused on pipeline transportation processes, pipe evaluation, and safe operation guarantees. There are still technical challenges in hydrogen-mixed natural gas pipelines in terms of the doping ratio and hydrogen separation and purification. To promote the industrial application of hydrogen energy, it is necessary to develop more efficient, low-cost, and low-energy-consumption hydrogen storage materials.

Heterogeneous Catalysts in N-Heterocycles and Aromatics as Liquid Organic Hydrogen Carriers (LOHCs): History, Present Status and Future.

The continuous decline of traditional fossil energy has cast the shadow of an energy crisis on human society. Hydrogen generated from renewable energy sources is considered as a promising energy carrier, which can effectively promote the energy transformation of traditional high-carbon fossil energy to low-carbon clean energy. Hydrogen storage technology plays a key role in realizing the application of hydrogen energy and liquid organic hydrogen carrier technology, with many advantages such as storing hydrogen efficiently and reversibly. High-performance and low-cost catalysts are the key to the large-scale application of liquid organic hydrogen carrier technology. In the past few decades, the catalyst field of organic liquid hydrogen carriers has continued to develop and has achieved some breakthroughs. In this review, we summarized recent significant progress in this field and discussed the optimization strategies of catalyst performance, including the properties of support and active metals, metal-support interaction and the combination and proportion of multi-metals. Moreover, the catalytic mechanism and future development direction were also discussed.

Microstructure, hydrogen permeability and ductile-to-brittle transition-hydrogen concentration of (V, Nb)-Ti-Co quaternary alloys

The ongoing development of hydrogen permeation alloys promotes the wide application of hydrogen energy, especially in the industry of hydrogen production from the water-gas shift reaction (WGS). However, before being widely used, it is still necessary to improve their comprehensive properties, such as hydrogen permeation flux and durability. Pd and its alloy membranes have been deeply studied and have appeared in the market in recent years. Vanadium-based alloys, as a new substitute for these palladium membranes, not only have lower cost but also higher hydrogen permeability. However, huge challenges remain-especially the poor mechanical stability and high susceptibility to hydrogen embrittlement (HE) which is closely related to high absorbed hydrogen concentration of Vanadium. To solve these problems, this paper investigated the structure, hydrogen diffusion, hydrogen dissolution, and hydrogen embrittlement properties of vanadium-based quaternary (V-Nb-Ti-Co) alloys. On this basis, the boundary of ductile brittle transition hydrogen concentration (DBTC) was described. It was found that new phases (such as Co2(V, Nb)3, Co7Nb6 etc.) will be formed in the structure when V is gradually replaced by Nb. Accordingly, the above changes the gradual substitution of V by Nb increased the hydrogen diffusivity and decreased hydrogen absorption. The overall effect is that the permeability decreases first and then increases, but larger hydrogen absorption will weaken the mechanical strength. As a result, the DBTC of the V-Nb-Ti-Co alloys shifts to the right somewhat (about 0.36 (H/M)), expanding the gap of the V-based single-phase alloys. This work demonstrated that the lower limit of DBTC can be adjusted by adding an appropriate amount of Nb in V-based alloys, thus simultaneously increasing the hydrogen permeability and hydrogen embrittlement resistance. This provides help and guidance for the design of novel hydrogen purification alloys.

Ultrafast synthesis of halogen-doped Ru-based electrocatalysts with electronic regulation for hydrogen generation in acidic and alkaline media

Developing a facile and time-saving method for preparing hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts can accelerate the practical applications of hydrogen energy. In this study, halogen (X = F, Cl, Br and I) doped Ru-RuO2 on carbon cloth (CC) (X-Ru-RuO2/MCC) was synthesized via an ultrafast microwave-assisted method for 30 s. Particularly, the doped Br (Br-Ru-RuO2/MCC) significantly improved the electrocatalytic performances of the catalyst through the regulation of electronic structures. Then, the Br-Ru-RuO2/MCC catalyst featured HER overpotentials of 44 mV and 77 mV in 1.0 M KOH and 0.5 M H2SO4, and the OER overpotential of 300 mV at 10 mA cm−2 in 1.0 M KOH. This study provides a novel method for developing of halogen-doped catalysts.

Experimental investigation of Pt membrane on ZrVFe hydrogen storage alloy for hydrogen elimination performance

Hydrogen safety is a primary obstacle to the widespread use of hydrogen energy, and the risk of hydrogen utilization can be avoided by eliminating unnecessary hydrogen immediately. Here we report a new kind of hydrogen elimination catalyst based on ZrVFe hydrogen storage alloy supported Pt. The chemical reduction temperature and the Pt loading have a great influence on the hydrogen elimination performance. When the reduction temperature is 60 °C and the Pt loading is 2 wt%, the ZrVFe/Pt catalyst exhibits excellent hydrogen elimination ability at 2–20 vol% hydrogen concentration, especially the efficiency of hydrogen elimination at 20 vol% hydrogen concentration is as high as 99%. The hydrogen adsorption capacity of the ZrVFe/Pt catalyst was 13 times higher than that of the commonly used metal carrier FeCrAl/Pt catalyst. This work paves a new direction for the design and on-going development of hydrogen elimination catalyst for hydrogen energy applications.

Dual Modification of Stainless Steel by Small Molecule Oxalic Acid for Oxygen Evolution Reaction

A electrocatalyst with low cost and high performance is the key to achieve the industrial application of hydrogen energy. In this work, inexpensive commercial stainless steel is modified by a simple hydrothermal method. For the first time, surface corrosion modification and active substance loading are realized simultaneously with small-molecule oxalic acid. Compared with 304-type stainless steel mesh (SSM-304), the overpotential of the sample after two-step treatment (noted as OESSM) is largely decreased (125 mV), and exceptional stability (48 h) is achieved. In acidic hydrothermal corrosion, the metal on the surface of stainless steel is eroded into the solution. Then, the C2O42– recomplexes with the dissolved metal ions, and the oxalate is grown on the surface. The excellent catalytic activity and stability come from the unique framework structure of the metal oxalate crystals. Oxalic acid is widely available and with double carboxyl group in C2O42–. The electrons enriched in C═O can enhance the adsorption energy on the catalyst surface and induce the production of active catalytic sites *OOH. In addition, the oxalate crystal framework provides critical support for maintaining positive catalytic activity and stability. This work creates the possibility of realizing the large-scale application of stainless steel-based electrocatalysts in actual production.