Route For Hydrogen Production Research Articles

A Comparative Exergoenvironmental Assessment of Thermochemical Copper-chlorine Cycles for Sustainable Hydrogen Production

Hydrogen is one of the highly promising clean solutions to address the concerns of energy security in the future given the rapid rate of depletion of naturally occurring hydrocarbon sources. However, it is of immense importance that hydrogen is obtained through sources that ensure sustainability. Thermochemical water-splitting processes are among such routes of hydrogen production that are both sustainable and environmentally benign. Thus, this study focuses on assessing the copper-chlorine thermochemical cycles that are among the more promising cycles of the chlorine family in terms of efficiency and cost-effectiveness. Moreover, this study considers a comparative exergoenvironmental evaluation of the four variants of the copper-chlorine cycle that vary in the number and the nature of steps. A comparison in this regard is carried out between the various steps of each cycle in terms of the component-associated environmental impact rates and environmental impact rates of energy transfer as well as the overall environmental impacts of all cycles. In addition, a comparison of the global warming potential of hydrogen synthesized through utilizing various electricity sources is also performed. Based on our evaluations, hydrolysis and electrolysis are the common steps in the five-step cycle, the four-step cycle, and the three-step cycle configuration 1 yielding the highest component-associated environmental impact rates and environmental impact rates of energy transfer, respectively. Conversely, in the three-step cycle configuration 2, the electrolysis and thermal decomposition steps yield the highest corresponding values, respectively. In addition, the three-step cycle configuration 2 (4,869 mPts/h) and the five-step cycle (3,194 mPts/h) have the highest and the lowest component-associated environmental impact rates, respectively while the five-step (530,694 mPts/h) and the four-step (248,050 mPts/h) cycles result in the highest and the lowest environmental impact rates of energy transfer, respectively.

Negative net global warming potential hydrogen production through biomass gasification combined with chemical looping: Environmental and economic assessments

The integration of biomass gasification (BG) with chemical looping hydrogen production (CLHP) offers one prospective approach for green hydrogen production. The environmental and economic assessments are conducted to evaluated the sustainable performance of the BG-CLHP system during the hydrogen production cycle (HPC). The results showed that the environmental impacts of BG-CLHP are concentrated in freshwater aquatic ecotoxicity (FAETP), human toxicity (HTP), and acidification (AP). The BG-CLHP system can provide a more cost-competitive hydrogen supply solution for hydrogen refueling stations compared the offshore wind or photovoltaic (PV) powered electrolysis, given the same hydrogen production target. For global warming potential (GWP) and cost, the BG-CLHP demonstrates excellent integrated performance with GWP values of −15.13 and −17.00 kg CO2, eq/kg H2, for the Air case and Oxygen case, and the costs of 3.05 and 2.82 $/kg H2, respectively, and sensitivity analysis reveals that the CLHP stage is the primary contributor to GWP. Compared with existing hydrogen production routes, BG-CLHP can still be improved in terms of costs and the technical maturity, however, the excellent negative GWP properties of BG-CLHP make it will play a more important role in future large-scale hydrogen production.

Pt/Ni single-atom alloy boosts mechano-pyrolysis of alkane into hydrogen

Mechanochemistry approach was utilized to solve the carbon deposition during alkane pyrolysis process. Pt/Ni single-atom alloy (SAA) was constructed on Ni balls surface as catalyst and grinding medium simultaneously, and physical collision of metallic balls generated mechanical energy to remove the deposited carbon and accelerate reaction rates. XANES spectra proved Pt/Ni SAA structure on the Ni ball surface, and its turnover frequency (TOF) was 1530 h−1 under 1 atm and 450 °C without by-products. An extremely long lifetime of methane pyrolysis at least 350 h on stream has been obtained. This Pt/Ni SAA was also active for mechano-pyrolysis of ethane/propane, and DFT calculations confirmed that the improvement of catalytic efficiency originated from the d-band center up-shifting under mechanic stress on Pt/Ni SAA surface. This mechanical catalysis study provides an alternative route for clean hydrogen production and a strategy for deposited carbon removal under mechanical conditions.

The formation of unsaturated IrOx in SrIrO3 by cobalt-doping for acidic oxygen evolution reaction

Electrocatalytic water splitting is a promising route for sustainable hydrogen production. However, the high overpotential of the anodic oxygen evolution reaction poses significant challenge. SrIrO3-based perovskite-type catalysts have shown great potential for acidic oxygen evolution reaction, but the origins of their high activity are still unclear. Herein, we develop a Co-doped SrIrO3 system to enhance oxygen evolution reaction activity and elucidate the origin of catalytic activity. In situ experiments reveal Co activates surface lattice oxygen, rapidly exposing IrOx active sites, while bulk Co doping optimizes the adsorbate binding energy of IrOx. The Co-doped SrIrO3 demonstrates high oxygen evolution reaction electrocatalytic activity, markedly surpassing the commercial IrO2 catalysts in both conventional electrolyzer and proton exchange membrane water electrolyzer.

Tetrametallic mastery: Cluster-doped graphdiyne as a superior electrocatalyst for hydrogen evolution

Hydrogen evolution reaction (HER) is a promising route for sustainable hydrogen production. However, its efficiency is limited by kinetic barriers. Herein, we employ density functional theory (DFT) calculations to demonstrate a new strategy of embedding tetrametallic transition metal clusters (3TM1-TM2) into the pores of graphdiyne (GDY) to effectively optimize its HER performance. By screening 900 configurations, 10 prototypes displayed near-ideal hydrogen adsorption free energies. Among them, 3W–Hg@GDY with a ΔGH of −0.00035 eV was identified as the optimal candidate. Analysis of the electronic structure reveals hybridization between the metal d orbitals and GDY p orbitals near the Fermi level, creating partially filled impurity states to promote hydrogen adsorption. Additionally, coordination between the three TM1 atoms and active TM2 atom in the cluster enables precise tuning of TM2's electron density to achieve a moderate interaction with the adsorbed H, facilitating superior HER catalysis. Our findings showcase a new paradigm of cluster engineering for modulating GDY's reactivity that holds great promise as a universal approach for the design of high-performance GDY-based electrocatalysts beyond HER.

Optimized Transition Metal Phosphides for Direct Seawater Electrolysis: Current Trends.

Seawater electrolysis presents a viable route for sustainable large-scale hydrogen production, yet its practical application is hindered by several technical challenges. These include the sluggish kinetics of hydrogen evolution, poor stability, cation deposition at the cathode, electrode corrosion, and competing chloride oxidation at the anode. To overcome these obstacles, the development of innovative electrocatalysts is crucial. Transition metal phosphides (TMPs) have emerged as promising candidates owing to their superior catalytic performance and tunable structural properties. This review provides a comprehensive analysis of recent progress in the structural engineering of TMPs tailored for efficient seawater electrolysis. We delve into the catalytic mechanisms underpinning hydrogen and oxygen evolution reactions in different pH conditions, along with the detrimental side reactions that impede hydrogen production efficiency. Several methods to prepare TMPs are then introduced. Additionally, detailed discussions on structural modifications and interface engineering tactics are presented, showcasing strategies to enhance the activity and durability of TMP electrocatalysts. By analyzing current research findings, our review aims to inform ongoing research endeavors and foster advancements in seawater electrolysis for practical and ecologically sound hydrogen generation.

Boosting hydrogen production from alkaline water splitting by regulating interlayer stress via lattice mismatch in NiS/MoS2

Alkaline water splitting currently represents one of the most promising routes for sustainable hydrogen production. However, the key challenge with this method lies in the development of low-cost catalysts showing high-performance for hydrogen evolution reaction (HER). Given the rapid advances in the structural design of HER catalysts, a potential procedure to boost their performance is introduced herein. A controllable interlayer stress is generated at the homojunction NiS/NiS interface of electrodeposited hybrid transition metal sulphide NiS/MoS2, by precisely regulating lattice mismatches of NiS nanostructures, achieve a precise control over its charge transfer resistance and the effective balance of electrochemical area. Accordingly, an optimal design, NM5030 (NiS(50 mA/cm2)-NiS(20 mA/cm2)/MoS2/CC), showing an excellent HER performance in alkaline electrolyte is produced. It can drive a high current density of 10 mA/cm2, 100 mA/cm2 and 400 mA/cm2 at a low overpotential of 18 mV, 93 mV and 161 mV, respectively. Under chronoamperometric test, no obvious reduction in current density is observed after 48 h, indicating its high stability. Overall, this work demonstrates the feasibility and effectiveness of the strategy of fabricating lattice mismatch to find an optimal layered structure based catalyst for efficient HER.

Comparison of life cycle assessment between hydrogen production from silicon waste and alkaline water electrolysis

With global warming becoming increasingly severe, environmental issues are receiving international attention. Crystalline silicon is an indispensable and important raw material for photovoltaic and semiconductor fields, but the cutting of crystalline silicon materials generates a large amount of silicon wastes. This article evaluates the environmental impact of a hydrogen production process using diamond-wire sawing silicon waste (DSSW) using the life cycle assessment (LCA) methodology. For comparison, it was also analyzed the environmental impact of the alkaline water electrolysis (AEL) hydrogen production route. In the DSSW alkaline catalyzed hydrolysis (DACH) hydrogen production route, the hydrogen production stage accounts for the main contribution of nine environmental impact indexes, including GWP, PED, ADP, AP, EP, ODP, ET, HT-cancer, and HT-non cancer, exceeding 56 %. Whereas for the AEL route, the environmental impacts of the electrolytic cell manufacturing stage can be neglected, and the operating stage contributes almost all the environmental impacts, contributing more than 92 % to the twelve environmental impact indexes. Compared to the AEL route, the DACH route has higher environmental impacts, with GWP index reaching 87.78 kg CO2 -eq/kg H2, PED index reaching 1772.90 MJ/kg H2, and IWU index reaching 622.37 kg/kg H2 which are 2.85, 4.07 and 7.56 times higher than the former, respectively. Although the environmental impact of the DACH route is significant, most of its indirect impacts were caused by the use of raw materials, and the energy consumption and direct environmental impact are both low. The environmental impact of the AEL route is mainly indirect effects generated due to the use of electricity. If clean renewable energy sources (e.g., solar PV, hydropower, geothermal or biofuels), were used for the AEL route, all twelve environmental impact indexes would be significantly reduced.

Cyan Hydrogen Process: A New Route for Simultaneous Hydrogen Production and Carbon Valorization.

Hydrogen is expected to largely contribute to the near-future circular economy. Today, most hydrogen is still produced from fossil fuels or renewable pathways with low efficiency and high cost. Herein, a proof of concept for a novel hydrogen production process is proposed, here named cyan hydrogen, inspired by a combination of the green and blue processes, due to the key role played by water and the low carbon content in the gas phase, respectively. The developed novel process, recently patented and demonstrated at the lab scale, is based on successive steps in which ethanol (5.0 mL) and water (10.0 mL) are alternately fed, with a fixed initial amount of sodium metaborate (2.0 g), in a batch reactor at 300 °C. Preliminary results showed the simultaneous production of a 95% v/v hydrogen stream, a polymeric byproduct with a repetitive carbon pattern -CH2-CH2-, and a liquid phase rich in oxygenated chemicals at temperatures lower than conventional hydrogen production processes.

Microbial activity of lactic acid bacteria and hydrogen producers mediated by pH and total solids during the consolidated bioprocessing of agave bagasse

Lactic acid bacteria (LAB) coexist with Clostridium spp. in hydrogen production processes from complex substrates; however, the role of LAB is still unclear. This study analyzed the fermentation products in a wide range of initial pH (pHi, 5.5–6.9) and total solids (TS%, 8–22%) to determine the activity of these two microbial groups over time (from 24 to 120 h). Agave bagasse served as the feedstock for hydrogen production via consolidated bioprocess (CBP), while the inoculum source was the indigenous mature microbiota. In the early stage of the CBP, hydrogen production from lactic acid occurred only at pHi ≥ 6.0 (ρ = 0.0004) with no effect of TS%; lactic acid accumulated below this pHi value. In this stage, lactic acid production positively correlated with a first cluster of LAB represented by Paucilactobacillus (r = 0.64) and Bacillus (r = 0.81). After 72 h, hydrogen production positively correlated with a second group of LAB led by Enterococcus (r = 0.71) together with the hydrogen producer Clostridium sensu stricto 1 (r = 0.8) and the acetogen Syntrophococcus (r = 0.52) with the influence of TS% (ρ < 0.0001). A further experiment showed that buffering the pH to 6.5 increased and lengthened the lactic acid production, doubling the hydrogen production from 20 to 41 mL H2/gTSadded. This study confirmed the prevalence of distinct groups of LAB over time, whose microbial activity promoted different routes of hydrogen production.

Renewable and high-purity hydrogen from lignocellulosic biomass in a biorefinery approach

Unprecedented efforts are being deployed to develop hydrogen production from bioresources in a circular economy approach, yet their implementation remains scarce. Today’s Challenges are associated with the shortage in the value chain, lack of large-scale production infrastructure, high costs, and low efficiency of current solutions. Herein, we report a hydrogen production route from cellulose pulp, integrating biomass fractionation and gasification in a biorefinery approach. Softwood sawdust undergoes formic acid organosolv treatment to extract cellulose, followed by steam gasification. High-purity hydrogen-rich syngas at a concentration of 56.3 vol% and a yield of 40 gH2/kgcellulose was produced. Char gasification offers the advantage of producing free-tar syngas reducing cleaning costs and mitigating downstream issues. A comprehensive assessment of mass and energy balance along the hydrogen value chain revealed an efficiency of 26.5% for hydrogen production, with an energy requirement of 111.1 kWh/kgH2. Optimizing solvent recovery and valorization of other constituents as added-value products in a biorefinery approach would further improve the process and entice its industrial takeoff.

Process modelling and assessment of thermochemical sulfur-iodine cycle for hydrogen production considering Bunsen reaction kinetics

Thermochemical sulfur-iodine (SI) cycle is one of the large-scale, clean, and efficient hydrogen production routes. The Bunsen reaction process is always simulated by a stoichiometric reaction, without considering the realistic Bunsen reaction kinetic process. Herein, a user-defined Fortran module concerning Bunsen reaction kinetics was developed and embedded into a continuous stirred tank reactor (RCSTR), and then a SI flowsheet with 100 L/h hydrogen production was modelled. The key parameter optimization, mass and energy balance were analyzed, the internal heat exchange network was created using the pinch point temperature difference analysis and the principle of energy cascade utilization, along with thermal efficiency evaluation. Bunsen reaction process reaches equilibrium after a period, which is consistent with experiments. The increase of H2SO4 decomposition ratio is beneficial to reduce the energy consumption of system. Increase in temperature has less effect on increasing the equilibrium decomposition ratio of HI. The theoretical thermal efficiency of system reaches 14.0-57.4% considering the recovery of exothermic heat. This work provides a theoretical basis for the optimization of SI cycle.

Economic Evaluation and Technoeconomic Resilience Analysis of Two Routes for Hydrogen Production via Indirect Gasification in North Colombia

Hydrogen has become a prospective energy carrier for a cleaner, more sustainable economy, offering carbon-free energy to reduce reliance on fossil fuels and address climate change challenges. However, hydrogen production faces significant technological and economic hurdles that must be overcome to reveal its highest potential. This study focused on evaluating the economics and technoeconomic resilience of two large-scale hydrogen production routes from African palm empty fruit bunches (EFB) by indirect gasification. Computer-aided process engineering (CAPE) assessed multiple scenarios to identify bottlenecks and optimize economic performance indicators like gross profits, including depreciation, after-tax profitability, payback period, and net present value. Resilience for each route was also assessed, considering raw material costs and the market price of hydrogen in relation to gross profits and after-tax profitability. Route 1 achieved a gross profit (DGP) of USD 47.12 million and a profit after taxes (PAT) of USD 28.74 million, while Route 2 achieved a DGP of USD 46.53 million and a PAT of USD 28.38 million. The results indicated that Route 2, involving hydrogen production through an indirect gasification reactor with a Selexol solvent unit for carbon dioxide removal, demonstrated greater resilience in terms of raw material costs and product selling price.

Current Trends of Iridium‐Based Catalysts for Oxygen Evolution Reaction in Acidic Water Electrolysis

The proton exchange membrane water electrolysis (PEMWE) powered by renewable electricity offers a facile route for clean hydrogen production. The oxygen evolution reaction (OER) at the anode plays a major role in affecting the overall device efficiency due to its sluggish OER kinetics. Thus, it remains a challenge to develop robust and active catalysts for OER in acid media for efficient PEMWE. Currently, iridium (Ir)‐based materials, such as mono‐ and multimetallic Ir, Ir‐based oxides, pyrochlore iridate oxides, and Ir‐based perovskites, are the most promising OER catalysts in acid media for PEMWEs. Extensive research has been conducted to enhance the specific activity of Ir species to make cost‐effective. The present review aims to provide the recent progress on addressing the long‐term durability issue of Ir‐based catalyst for OER in acidic conditions, aspiring to inspire the researchers to design highly efficient and stable Ir‐based catalysts. Moreover, the detailed OER mechanism along with the dissolution nature of Ir species is discussed and summarized. Finally, the status, challenges, and prospects for the development of Ir‐based OER catalysts are discussed.

Iron-doped cobalt nitride as an efficient electrocatalyst towards energy saving hydrazine assisted seawater splitting in near neutral to highly alkaline pH achieving industry level current density

Replacing sluggish anodic oxygen evolution reaction by hydrazine oxidation reaction in seawater electrolysis is one of the smartest ways of getting multiple benefits as it offers an energy saving route for hydrogen production keeping the cell voltage way smaller than responsible voltage for corrosive chloride oxidation. Here, we report iron-doped Co3N as highly active electrocatalyst towards hydrazine oxidation reaction and hydrogen evolution reaction in wide pH range of 7–14. The two-electrode electrolyser system reached industry scale current density of 1000 mA cm−2 at ultralow cell voltage of 0.65 V, and found sustainable at 500 mA cm−2 over 95 h in hydrazine assisted alkaline seawater splitting. The electrolyser system also achieved 200 mA cm−2 current density at 0.75 V in hydrazine assisted neutral seawater medium. Interestingly, a thin amorphous iron oxide layer formed in Fe-doped Co3N provided much needed protection during electrocatalysis offering long term stability at industry level current density.

Medium and long-term hydrogen production technology routes and hydrogen energy supply scenarios in Guangdong Province

Hydrogen is a type of clean secondary energy, and the hydrogen energy supply is vital to regional energy development. Guangdong is at the forefront of hydrogen energy deployment in China, and aims to achieve peak carbon by 2030. However, hydrogen production research is challenging due to complex technical routes, technical maturity levels, life-cycle carbon emissions, and costs. Multi-time-scale research is necessary to explore optimal production paths and their contributions to CO2 emission reduction. This study discussed key technologies and the technical maturity of five hydrogen production routes: production from industrial byproducts and coal, wind, hydro-, and photovoltaic power. Policy scenarios were designed to investigate the potential of these routes and technology deployment intensity under medium- and long-term scenarios. This paper proposes a roadmap for hydrogen development and provides a reference for hydrogen production planning in Guangdong. This methodology can be applied in other regions for hydrogen energy development research.

Process modeling and integration of hydrogen and synthetic natural gas production in a kraft pulp mill via black liquor gasification

The black liquor gasification integrated to chemical plants has shown potential for reducing the process irreversibility and promoting the decarbonization of this industrial sector. In the integrated chemical plants proposed in this work, the purpose is co-producing pulp and gaseous fuels, either hydrogen or synthetic natural gas, in order to expand the biorefinery product portfolio and, consequently, increase the plant revenues. However, due to additional equipment and utility demands, along with the uncertainty about the prices of the commodities; the benefits of the integrated setups must be thoroughly weighed by considering thermodynamic, economic and environmental indicators before the retrofit of the existing configuration is implemented. The exergy method is used along with the energy integration technique and other financial indicators to determine whether and in which scenarios the integrated biorefineries would be more attractive. The average exergy efficiency of the integrated chemical production plants is 44%, which is higher than that of the conventional case (40%). The balance of the overall CO2 emissions vary from 1.97 to −0.56 tCO2/tPulp, for the conventional and integrated setups, respectively. An incremental financial analysis under uncertainty also shows that the hydrogen production route with partial import of electricity and carbon taxations above 60 EUR/tCO2 outperforms the other scenarios. Therefore, the import of electricity from low-carbon grids and the upgrade of biorefinery residues arise as key factors for ensuring the sustainable production of traditionally fossil-based chemicals under more stringent environmental regulations.

Recent advances in efficient and scalable solar hydrogen production through water splitting

Solar hydrogen production through water splitting is the most important and promising approach to obtaining green hydrogen energy. Although this technology developed rapidly in the last two decades, it is still a long way from true commercialization. In particular, the efficiency and scalability of solar hydrogen production have attracted extensive attention in the field of basic research. Currently, the three most studied routes for solar hydrogen production include photocatalytic (PC), photoelectrochemical (PEC), and photovoltaic-electrochemical (PV-EC) water splitting. In this review, we briefly introduce the motivation of developing green hydrogen energy, and then summarize the influential breakthroughs on efficiency and scalability for solar hydrogen production, especially those cases that are instructive to practical applications. Finally, we analyze the challenges facing the industrialization of hydrogen production from solar water splitting and provide insights for accelerating the transition from basic research to practical applications. Overall, this review can provide a meaningful reference for addressing the issues of efficiency improvement and scale expansion of solar hydrogen production, thereby promoting the innovation and growth of renewable hydrogen energy industry.Graphical

Enhanced morphological maintenance and redox stability by dispersing nickel ferrite into silica matrix for chemical looping hydrogen production via water splitting

Chemical looping hydrogen production (CLHP) is widely regarded as a clean and efficient route for high purity hydrogen production. However, a huge barrier is how to avoid serious deactivation caused by sintering and agglomeration of oxygen carriers. A novel fabrication process of highly dispersing NiFe2O4 into silica matrix is proposed. The oxygen carriers of NiFe2O4 completely dispersed over silica matrix (NFSM) are successfully synthesized. The characterizations, hydrogen production capacity and cycle redox performance of oxygen carriers are further investigated. The results illustrate that NiFe2O4 active components are homogeneously dispersed on the silica matrix without any impurities. NFSM demonstrates the highest reactivity with CO as well as the greatest hydrogen production of 296 mL/g due to the strong confinement effect of silica matrix and good particle dispersion. The porous silica matrix offers large amounts of channels for the lattice oxygen transport and effectively prevents Fe and Ni cations outward migration to particle surface, which actually inhibits the larger clusters and sintering. NFSM can keep stable hydrogen production of approximately 290 mL/g during the cyclic experiments. Briefly, the innovation method of embedding active component into well-established silica matrix supports contributes to the enhanced anti-sintering properties and redox stability of oxygen carriers.

Anti-coking Cu-Ni bimetallic catalyst for hydrogen production: Thermodynamic and experimental study of methanol autothermal reforming

Autothermal reforming has emerged as a promising route for hydrogen production from bio-methanol, offering a balance between hydrogen production and the energy demand of the process. To address the low catalytic performance of non-precious metal catalysts, one of the approaches is to introduce a second metal. In this work, a series of Cu-Ni bimetallic catalysts derived from Ca-Al hydrotalcite-like compounds were prepared by the urea hydrolysis method combined with hydrothermal treatment, featuring well-dispersion with a size of 3-5 nm. The electron redistribution triggered by the incorporation of Cu enhances the absorption of methanol at the electron-poor surface, leading to maintained catalytic activity at 450°C for 96 hours with few carbon-deposition observed for methanol autothermal reforming. The boundary conditions of the thermal-neutrality system are analyzed by thermodynamic calculations and similar trends to the simulation results were also obtained from experiments.