Hydrogen Energy Source Research Articles

Hydrogen and syngas production from catalytic steam gasification of char derived from ion-exchangeable Na- and Ca-loaded coal

Catalytic steam gasification of char derived from low-rank coal possesses substantial potential as a source of hydrogen energy and syngas feedstocks, and its performances are largely associated with the employed catalysts. Therein, ion-exchangeable Na or Ca species are always regarded as excellent in-situ catalysts in low-rank coal. In this paper, gasification of Na-Char, Ca-Char and a Na/Ca-Char mixture with different partial pressures of steam was performed within a temperature range of 700–900 °C using a micro fluidized bed reaction analyzer. The results indicate that Na and Ca species could accelerate the gas release rate during gasification and even significantly increase H2 production, in sharp contrast to non-catalytic gasification. Variations in the product gases during Na-Char and Ca-Char gasification were completely different, which associated with the different deactivation pathways and catalytic reaction mechanisms of Na and Ca catalysts. With an increasing gasification temperature, the decreasing trend of H2 production for Na-Char gasification was mainly due to the loss of Na during gasification. Conversely, the enhancement of Ca activity promoted the H2 production. The H2/CO ratio of Ca-Char gasification at 700 °C approximately ranged from 1.0 to 2.0 as a function of the partial pressure of steam, which suggested catalytic gasification can be suitable for hydrogen-rich production and subsequent synthesis reactions. In addition, gasification of Na/Ca-Char mixture produced a higher hydrogen content in the product gases than that of Na-Char or Ca-Char gasification alone, particularly for the 30%Na/70%Ca-Char mixture. It implies that the high H2 production of 70%Ca30%Na-Char mixture was attributed to the cooperative effects of the Na and Ca species on the catalytic activity. This study provides comprehensive information regarding the effects of ion-exchangeable Na, Ca and a Na/Ca mixture on the hydrogen production and syngas composition during steam gasification, which provides new insight into the utilization of low-rank coal.

Pt-Pd co-electrodeposited nitrogenous loofah sponge as efficient pH-universal electrocatalyst for hydrogen evolution reaction

Hydrogen, a clean, renewable and efficient energy source, is considered to be one of the most appropriate candidates for traditional fossil fuels. As the most important part of the hydrogen evolution reaction (HER), HER catalysts are receiving ever increasing attention in recent years. In this work, an activated nitrogenous loofah sponge (NLS) with similar nanosheets structure like graphene and MoS2, was introduced as the nanocarbon substrate. Then, Pt, Pd and PtPd nanoparticle modified activated loofah sponge nanocomposites (Pt@NLS, Pd@NLS, PtPd@NLS) were simply obtained via electrochemical deposition in different electrolytes. The HER performances of Pt@NLS, Pd@NLS and PtPd@NLS were fully investigated in both acid and alkaline conditions, which indicated that the PtPd@NLS (electrodeposition for 10 s) with 6.95 wt% Pt and 8.65 wt% Pd had best HER performance in both solutions. The overpotentials of the PtPd@NLS (@ 10 mA cm−2) in 0.5 M H2SO4 and 1.0 M KOH were 29 and 46 mV, respectively. The corresponding Tafel slopes were 23 and 124 mV dec−1, which were quite comparable to the Pt/C (10 wt%). The PtPd@NLS also showed good long-term stability in both media.

NiMoS3 Nanorods as pH-Tolerant Electrocatalyst for Efficient Hydrogen Evolution

To meet the increasing demands for sustainable and clean hydrogen energy sources, development of pH-tolerant electrocatalysts with high-performance and low-cost toward hydrogen evolution reaction (HER) is an important but challenging task. MoS2 is postulated as a promising candidate for HER in acidic solution, however, showing poor activity in alkaline media. Herein, to widen its application in various media, we first report the synthesis of NiMoS3 nanorods using a hydrothermal method that starts from NiMoO4 nanorods. The incorporation of Ni atoms in Mo–S could arouse the synergism of ternary Ni–Mo–S and create abundant defect sites, thus substantially improving the inherent catalytic activity and catalytic sites. More importantly, Ni endows Mo–S with excellent catalytic activity in alkaline solution. As a result, NiMoS3 exhibits large cathodic current, low overpotetnial, and stable durability for HER in H2SO4 and especially in KOH. The overpotetnial at current density of 10 mA cm–2 is as low as 126 mV in KOH, making it a promising candidate for HER electrocatalyst.

Hydrogen energy sources with current inverters in ship AC power plants

The use of hydrogen energy sources is promising for the creation of ship electric-power systems. These sources have a number of significant advantages over conventional energy sources (diesel generators or turbine generators), such as the possibility to provide low-noise regimes of ship motion and creation of an airindependent shipboard power plant. Using hydrogen energy sources as components of electric-power systems along with conventional energy sources makes it possible to optimize the operation of diesel generators as regards minimum fuel consumption and provide a reserve of power. The article analyzes the structural variants of energy channels with hydrogen energy sources and current inverters providing parallel operation with diesel generators or turbine generators in ship ac electric-power plants. The problems of regulation and distribution of active and reactive powers between sources operating under a total load are considered. Comparative analysis of the generalized energy indicators and of the degree of distorting influence of energy channels with hydrogen energy sources on the voltage waveform of a ship electrical-power network in static operating modes is presented.

MoS2 nanosheets supported on reduced carboxylic multi-walled carbon nanotubes: An advanced catalyst for the hydrogen evolution reaction

One of the important breakthroughs in the realization of renewable hydrogen energy source is the development of innovative methods to produce non-noble-metal electrocatalysts for the hydrogen evolution reaction (HER). In this work, an efficient HER catalyst with a unique nanostructure that MoS2 nanosheets (NSs) supported on reduced carboxylic multi-walled carbon nanotubes (rCMWCNTs) has been synthesized by microwave-assisted. The preparation process is environmentally friendly, efficient, and suitable for mass production, including a liquid exfoliation technique of ultrasound probe sonication method to make small-sized MoS2 NSs and their subsequent microwave-assisted synthesis to be supported on rCMWCNTs. The study of the structural properties reveal that the MoS2 NSs supported on the rCMWCNTs are uniformly distributed and perfectly preserved their original superior structural features. The excellent catalytic performance of the as-prepared hybrid is verified by the electrochemical tests results, which exhibit a small Tafel slope of 66mV/decade and a low overpotential of −190mV. Moreover, according to the classic theory, the mechanism governing of the catalytic HER on the MoS2 NSs/rCMWCNTs nanohybrid has been clarified.

Integration of commercial alkaline water electrolysers with renewable energies: Limitations and improvements

Hydrogen can be stored, transported and used in a large number of applications in which fossil fuels are currently used. From a sustainable point of view, the synergy existing between hydrogen and renewable energy sources shows great potential. In this respect, hydrogen can be produced from water electrolysis using the electricity generated by renewable systems. This paper studies the integration of a 1 Nm3 h−1 alkaline water electrolyser with photovoltaic solar energy (PVE) and wind energy (WE) in a stand-alone system. In particular, a one year energy balance of the conventional integration of the electrolyser with PVE and WE is carried out. To do so, actual weather data are used for irradiance, ambient temperature and wind speed, in addition to the technical specifications and characteristics of a 6.8 kWp PV generator and a 6 kW wind turbine. This energy evaluation reveals the main limitations of commercial electrolysers, such as the lower operating limit and the number of stops permitted by manufacturers. Two strategies are therefore proposed to improve the integration of conventional electrolysers, namely to allow the electrolyser to operate for a period of 10 min under the lower operating limit and to integrate a battery bank. Both strategies achieve successful results, with a reduction in the number of stops by up to 62.1% for the PVE integration and 63.1% for the WE, which should increase the electrolyser service life, and an increase in energy efficiency by up to 6.3% for the PVE integration and 7.6% for the WE.

Ni&Mn nanoparticles-decorated carbon nanofibers as effective electrocatalyst for urea oxidation

Compared to alcohols, urea is considered an interesting hydrogen and electrical energy source as it is available in industrial and municipal wastes. Ni&Mn nanoparticles-decorated carbon nanofibers are introduced as effective and stable electrocatalysts for urea oxidation. The introduced decorated carbon nanofibers were synthesized by calcination of electrospun mats composed of nickel acetate, manganese acetate and poly(vinyl alcohol) in argon atmosphere at 850°C. The utilized characterization techniques, XRD, TEM, FE SEM and TEM-EDX analyses, confirmed formation of carbon nanofibers decorated by discrete Ni, Mn and NiMn nanoparticles and absence of any oxides. The electrochemical measurements indicated that the introduced nanofibers have good electrocatalytic activity toward urea oxidation as the observed current density was 300mAcm−2g−1 with an onset potential of 290mV (vs. Ag/AgCl). Moreover, the results proved that incorporation of manganese and the nanofibrous morphology distinctly enhance the electrocatalytic activity of nickel toward urea oxidation.

Autonomous power systems with synchronous generators and hydrogen energy sources

This article gives a brief overview of current developments in the application of hydrogen sources as part of the autonomous power systems of ships and trains. The variants of the block diagrams of autonomous electric power systems with diesel generators or turbine generators and hydrogen energy sources in which a hydrogen source works in parallel with a synchronous generator for the total load from the inverter of current and inverter of voltage have been considered. The energy performance indicators and features of management processes have been analyzed on the basis of a consideration of equivalent circuits with fundamental harmonics on stationary processes when the synchronous generator works in parallel with a hydrogen energy source supported by means of a current or voltage inverter for an active-inductive energy consumer. Comparative analysis of the advantages and disadvantages of the considered structural variants of autonomous power systems has been provided.

Review of fossil fuels and future energy technologies

Fossil fuels production peaks, declines and depletions depend on their proved reserves, exploration and consumption rates. Worldwide proven oil, gas and coal reserves are 1688billion barrels (Bb), 6558trillion cubic feet (TCF) and 891billion tons (Bt) being consumed at rates of 0.092Bb, 0.329TCF and 7.89BT per day, respectively. The oil, gas and coal reserves are increasing at the rate of 600million barrels (Mb), 400billion cubic feet (BCF) and 19.2Giga tons of oil equivalents (GTOE) per year. While the rate of annual increase in consumption of oil, gas and coal is 1.4Mb, 4.5BCF and 3.1million tons (Mt). Global annual energy demand of over 12billion tons of oil equivalent (BTOE) results in the emission of 39.5Giga tons of carbon dioxide (Gt-CO2), and the annual CO2 emission would increase up to 75 Gt-CO2 when future energy demand will rise to 24–25BTOE. Oil, gas and coal may continue to exist for next several decades, yet the energy transition to low carbon intensity fuels is necessary to cope with rampant climate change. Renewable and alternative energy sources hold key to the solution of twin problems, energy and climate change, with a high initial investment. Transition from fossil fuels to sustainable and renewable energy resources of 150Petawatt hours (PWh) requires major investment and innovatory technologies. Perhaps CO2 and H2O based fuel systems would facilitate climate change and grand energy transition. An energy mix consisting of fossil fuels, hydrogen, bio-fuels, and renewable energy sources seems to be a good initiative. This paper reviews evidence of hydrocarbons decline scenarios and timelines of future energy technologies.

Exploration of Extracting Hydrogen Energy with Converter Waste Gas

This paper introduces the advantage of hydrogen energy source and the state of recover. It given the Thermodynamic parameter of the shift reaction of water gas into the converter waste gas contain CO(g) of high quality, and the specification of the catalysis using the smoke of the converter waste gas (Fe3O4). The paper states the principle and the process of separating out H2 from the mixture gas (H2+CO2) by the pressure swing adsorption method (PSA).

Hydrogen and renewable energy sources integrated system for greenhouse heating

A research is under development at the Department of Agro- Environmental Sciences of the University of Bari “Aldo Moro” in order to investigate the suitable solutions of a power system based on solar energy (photovoltaic) and hydrogen, integrated with a geothermal heat pump for powering a self sustained heated greenhouse. The electrical energy for heat pump operation is provided by a purpose-built array of solar photovoltaic modules, which supplies also a water electrolyser system controlled by embedded pc; the generated dry hydrogen gas is conserved in suitable pressured storage tank. The hydrogen is used to produce electricity in a fuel cell in order to meet the above mentioned heat pump power demand when the photovoltaic system is inactive during winter night-time or the solar radiation level is insufficient to meet the electrical demand. The present work reports some theoretical and observed data about the electrolyzer operation. Indeed the electrolyzer has required particular attention because during the experimental tests it did not show a stable operation and it was registered a performance not properly consistent with the predicted performance by means of the theoretical study.

Hydrogen and renewable energy sources integrated system for greenhouse heating

A research is under development at the Department of Agro- Environmental Sciences of the University of Bari “Aldo Moro” in order to investigate the suitable solutions of a power system based on solar energy (photovoltaic) and hydrogen, integrated with a geothermal heat pump for powering a self sustained heated greenhouse. The electrical energy for heat pump operation is provided by a purpose-built array of solar photovoltaic modules, which supplies also a water electrolyser system controlled by embedded pc; the generated dry hydrogen gas is conserved in suitable pressured storage tank. The hydrogen is used to produce electricity in a fuel cell in order to meet the above mentioned heat pump power demand when the photovoltaic system is inactive during winter night-time or the solar radiation level is insufficient to meet the electrical demand. The present work reports some theoretical and observed data about the electrolyzer operation. Indeed the electrolyzer has required particular attention because during the experimental tests it did not show a stable operation and it was registered a performance not properly consistent with the predicted performance by means of the theoretical study.

Hydrogen: Technologies, Policies and Challenges

Hydrogen energy has been considered as a clean alternative energy source substituting fossil fuels. Many countries consider it as the ultimate solution to the energy and environmental problems, even draw up the blueprint of “hydrogen economy” and heavily invest for research and development. However, after decades of research, the hydrogen energy technologies are still being prospective and explored, and haven’t been put into large scale production by now. This article begins with expatiation on the essence of hydrogen energy, makes analysis of various big challenges for hydrogen energy technologies, and reaches the conclusion that we should hold the rational and cautious attitude towards hydrogen energy source because the transition to hydrogen economy of unclear prospect must pay a very high cost, which is unbearable for the social and economic development status of developing countries.

Polymer electrolyte membrane water electrolysis: status of technologies and potential applications in combination with renewable power sources

Technological improvements in polymer electrolyte membrane water electrolysers (PEMWEs) are promoted by their exciting possibilities to operate with renewable power sources. In this paper, a synopsis of the research efforts concerning with the development of electrocatalysts, polymer electrolytes and stack hardware components is presented. The most challenging problem for the development of PEMWEs is the enhancement of oxygen evolution reaction rate. At present, there are no practical alternatives to noble metal-based oxide catalysts such as IrO2 and RuO2. As well as carbon supported Pt nanoparticles are the benchmark cathode catalysts for hydrogen evolution. High noble metal loading on the electrodes and the use of perfluorosulfonic membranes significantly contribute to the cost of these devices. Critical areas include the design of appropriate mixed electrocatalysts and their dispersion on low cost Ti-oxide like supports to increase catalyst utilization. Moreover, the development of alternative membranes with enhanced mechanical properties for high pressure applications, proper conductivity and reduced gas cross-over is strongly required. This latter aspect is also addressed by the development of proper recombination catalysts. The development of anodic mixed non-noble transition metal oxides with spinel or perovskite structure and proper resistance to chemical degradation in the acidic environment and electrochemical corrosion is also an active area of research. Similarly, efforts are also being addressed to Pd and Ru based cathode formulations with cheaper characteristics than Pt. Whereas, concerning with stack hardware, cost reduction may be addressed by replacing Ti-based diffusion media and bipolar plates with appropriate and cost-effective stainless steel materials with enhanced resilience to chemical and electrochemical corrosion. Regarding the combination with renewable power sources, PEM electrolysers can find suitable applications for peak shaving in integrated systems grid connected or in grid independent operating conditions where hydrogen generated through electrolysis is stored and then via fuel cell converted back to electricity when needed or used to refill fuel cell-based cars. Hydrogen is the most promising clean energy carrier to accomplish the sustainable production of energy and a synergy among hydrogen, electricity and renewable energy sources is highly desired.

Production of hydrogen and light hydrocarbons as a potential gaseous fuel from microwave-heated pyrolysis of waste automotive engine oil

Waste automotive engine oil was pyrolyzed in a continuous stirred bed reactor using microwave energy as the heat source; the yield and characteristics of the incondensable gaseous products are discussed. The recovered gases (41 wt% yield) were found to contain substantial concentrations of light aliphatic hydrocarbons (up to 86 vol.%) that could potentially be used as a chemical feedstock or a fuel source to power the process, or to be reformed to produce hydrogen for use as a second-generation fuel. Examination of the composition of the gases also showed the formation of H2 (up to 19 vol.%) and CO that could also be used as a valuable syngas (with a H2 + CO content of up to 35 vol.%). The high yield of gaseous hydrocarbons can be attributed to the unique heating mode and chemical environment present during microwave-heated pyrolysis. The use of a microwave-heated bed of particulate-carbon showed advantages in transforming waste oil into valuable gases. Hence an environmentally unfriendly waste material can be transformed into a useful resource and serves as an alternative source of hydrogen or hydrocarbon energy. The recovery of valuable gases shows advantage over traditional destructive approaches and suggests excellent potential for recycling problematic waste oil.

Renewable Hydrogen Carrier — Carbohydrate: Constructing the Carbon-Neutral Carbohydrate Economy

The hydrogen economy presents an appealing energy future but its implementation must solve numerous problems ranging from low-cost sustainable production, high-density storage, costly infrastructure, to eliminating safety concern. The use of renewable carbohydrate as a high-density hydrogen carrier and energy source for hydrogen production is possible due to emerging cell-free synthetic biology technology—cell-free synthetic pathway biotransformation (SyPaB). Assembly of numerous enzymes and co-enzymes in vitro can create complicated set of biological reactions or pathways that microorganisms or catalysts cannot complete, for example, C6H10O5 (aq) + 7 H2O (l) à 12 H2 (g) + 6 CO2 (g) (PLoS One 2007, 2:e456). Thanks to 100% selectivity of enzymes, modest reaction conditions, and high-purity of generated hydrogen, carbohydrate is a promising hydrogen carrier for end users. Gravimetric density of carbohydrate is 14.8 H2 mass% if water can be recycled from proton exchange membrane fuel cells or 8.33% H2 mass% without water recycling. Renewable carbohydrate can be isolated from plant biomass or would be produced from a combination of solar electricity/hydrogen and carbon dioxide fixation mediated by high-efficiency artificial photosynthesis mediated by SyPaB. The construction of this carbon-neutral carbohydrate economy would address numerous sustainability challenges, such as electricity and hydrogen storage, CO2 fixation and long-term storage, water conservation, transportation fuel production, plus feed and food production.

Determination of trace borohydride in basic solutions using differential pulse polarography

Synthesis of borohydride is important because of its use as a hydrogen energy source. The objective of this study was to develop a new and simple method for the trace determination of borohydride so that it can be used during the investigation of a new reaction for its synthesis or in some kinetic studies. A differential pulse polarographic method has been developed for this purpose since the results obtained with this method are very reproducible and the instrument used is not expensive. The optimum working condition was found to be as 0.05 M phosphate buffer (pH 9), containing 0.1 M KNO_3 electrolyte. It allows trace determination of borohydride in the range of 10^{-4}-10^{-6} M using the oxidation peak at --0.06 V with high accuracy. The detection limit was 6 \times 10^{-7} M in phosphate buffer. The nature of the peak was evaluated using direct current polarography and it was found that this peak at --0.06 V was an oxidation peak. There was no serious interference from some cations such as Cr(III), Cr(VI), Fe(III), Cd(II), Pb(II), Zn(II), Ni(II), and Se(IV) and anions such as chloride, bromide, nitrate, and sulfite when 2-14 times of borohydride was present. It was found that only copper (II) had an overlapping peak. This interference of copper was eliminated by the addition of EDTA. Using this procedure, in the presence of 5 \times 10^{-5} M copper, for 2 \times 10^{-5} M borohydride the result found was (1.9 \pm 0.2)10^{-5} M for N = 3 and 90\% confidence interval.

The possibilities for hydrogen production from H<sub align=right>2S and storage in the Black Sea

The Black Sea, a highly isolated inland sea, is the largest anoxic zone in the world. Since the hydrogen sulphide (H2S) zone was discovered in the early 19th century in the Black Sea, it has been accepted that there is no life in the depths of the Black Sea and only bacteria live in the H2S layer. A high content of organic matter, with maximum processes of bacterial sulphate reduction, is the major source of this H2S zone. H2S is one of the most poisonous gases in the world, but it has great economic value to obtain hydrogen via dissociation into hydrogen and sulphur. Thus, the Black Sea not only has a serious environmental contamination, but is also a potential source of hydrogen energy if a decomposition process can be developed. In this study, a proposal is made for the production of hydrogen from hydrogen sulphate to be extracted from the waters of the Black Sea and storage by the natural sources of the Black Sea.

Fuels: Corn Ethanol Goal Revives Dead Zone Concerns

Fuels: Corn Ethanol Goal Revives Dead Zone Concerns

Non-toxic hydride energy source for biochemical and industrial venues: ORP and NAD + reduction analyses

A recently described novel compound, silica hydride, was used to investigate potential alternative hydrogen energy sources for use in industry, pharmacology and biochemistry. Acting as an anionic hydride, the silica hydride does not react violently with water and produces stable oxidation-reduction potential readings of greater than −860 mV for extended periods providing capacity as an alternative for current transfer, hydrogen production and fuel cell applications in industrial arenas. In a biological venue, the silica hydride definitively reduces the pyridine NAD + to the NADH form, indicating potential for use as a biochemical fuel cell. Subsequent analyses of the compound indicate no induced cytotoxicity as a result of the silica hydride and the increased NADH in a cell.