Green H2 Research Articles

Environmental system analysis on formic acid synthesis from captured CO2 and green H2 using life cycle assessment methodology

Abstract Hydrogen (H2) is highly promising as an alternative energy source because it does not emit CO2 when used; thus, H2 utilization is a potential solution to fossil fuel depletion and global warming. In our previous studies, green H2 was developed through biomass pyrolysis. Meanwhile, the development of carbon dioxide capture utilization technologies to recycle CO2 gas from fossil fuel is being considered. Moreover, formic acid (FA) synthesis is among the candidate procedures for utilizing captured CO2. FA is a vital chemical substance with numerous industrial applications. As the simplest carboxylic acid, FA produces various chemical products. The demand for FA will continue to increase, mainly due to recent technological advancements in fuel cells and renewable energy. The primary pathway for FA synthesis involves the hydrolysis of fossil fuel–derived formic acid methyl. In this study, we investigated FA synthesis using CO2 from fossil fuel and green H2 from biomass as raw materials. Subsequently, we evaluated the environmental impact of the synthesized FA compared with the conventional fossil fuel–derived FA by applying the life cycle assessment methodology. The evaluation focuses on Japan, aiming to reduce environmental impact as an evaluation metric while considering the constraints on CO2 emissions and H2 production scale. Furthermore, we sought to identify the conditions that would reduce the environmental impact of FA synthesis.

Energetic, Exergetic, and Techno-Economic Analysis of A Bioenergy with Carbon Capture and Utilization Process via Integrated Torrefaction–CLC–Methanation

Bioenergy with carbon capture and storage (BECCS) or utilization (BECCU) allows net zero or negative carbon emissions and can be a breakthrough technology for climate change mitigation. This work consists of an energetic, exergetic, and economic analysis of an integrated process based on chemical looping combustion of solar-torrefied agro-industrial residues, followed by methanation of the concentrated CO2 stream with green H2. Four agro-industrial residues and four Italian site locations are considered. Depending on the considered biomass, the integrated plant processes about 18–93 kg h−1 of raw biomass and produces 55–70 t y−1 of synthetic methane. Global exergetic efficiencies ranged within 45–60% and 67–77% when neglecting and considering, respectively, the valorization of torgas. Sugar beet pulp and grape marc required a non-negligible input exergy flow for the torrefaction, due to the high moisture content of the raw biomasses. However, for these biomasses, the water released during drying/torrefaction and CO2 methanation could be recycled to the electrolyzer to eliminate external water consumption, thus allowing for a more sustainable use of water resources. For olive stones and hemp hurd, this water recycling brings, instead, a reduction of approximately 65% in water needs. A round-trip electric efficiency of 28% was estimated assuming an electric conversion efficiency of 40%. According to the economic analysis, the total plant costs ranged within 3–5 M€ depending on the biomass and site location considered. The levelized cost of methane (LCOM) ranged within 4.3–8.9 € kgCH4−1 but, if implementing strategies to avoid the use of a large temporary H2 storage vessel, can be decreased to 2.6–5.3 € kgCH4−1. Lower values are obtained when considering hemp hurd and grape marc as raw biomasses, and when locating the PV field in the south of Italy. Even in the best scenario, values of LCOM are out of the market if compared to current natural gas prices, but they might become competitive with the introduction of a carbon tax or through government incentives for the purchase of the PV field and/or electrolyzer.

Critical Review of Life Cycle Assessment of Hydrogen Production Pathways

In light of growing concerns regarding greenhouse gas emissions and the increasingly severe impacts of climate change, the global situation demands immediate action to transition towards sustainable energy solutions. In this sense, hydrogen could play a fundamental role in the energy transition, offering a potential clean and versatile energy carrier. This paper reviews the recent results of Life Cycle Assessment studies of different hydrogen production pathways, which are trying to define the routes that can guarantee the least environmental burdens. Steam methane reforming was considered as the benchmark for Global Warming Potential, with an average emission of 11 kgCO2eq/kgH2. Hydrogen produced from water electrolysis powered by renewable energy (green H2) or nuclear energy (pink H2) showed the average lowest impacts, with mean values of 2.02 kgCO2eq/kgH2 and 0.41 kgCO2eq/kgH2, respectively. The use of grid electricity to power the electrolyzer (yellow H2) raised the mean carbon footprint up to 17.2 kgCO2eq/kgH2, with a peak of 41.4 kgCO2eq/kgH2 in the case of countries with low renewable energy production. Waste pyrolysis and/or gasification presented average emissions three times higher than steam methane reforming, while the recourse to residual biomass and biowaste significantly lowered greenhouse gas emissions. The acidification potential presents comparable results for all the technologies studied, except for biomass gasification which showed significantly higher and more scattered values. Regarding the abiotic depletion potential (mineral), the main issue is the lack of an established recycling strategy, especially for electrolysis technologies that hamper the inclusion of the End of Life stage in LCA computation. Whenever data were available, hotspots for each hydrogen production process were identified.

Ru dispersed on CeO2{1 0 0} facets boosting the catalytic NH3 decomposition for green H2 generation

A hydrothermal process was used to prepare CeO2 nanoparticles with mainly {100} facets and {110,100} facets, and a precipitation method was used to prepare CeO2 nanoparticles with mainly {111,100} facets for supporting Ru in NH3 decomposition studies. CeO2{100} promoted the formation of partially charged Ru (Ruδ+) species over Ru/CeO2{100}, leading Ru/CeO2{100} to perform the highest NH3 decomposition activity by desorbing re-combinative N2 efficiently. Density functional theory calculations have confirmed the Ru dispersed on terminated CeO2{100} with the high negative Bader charges for decreasing the formation energy of N2. In addition, the Cs addition significantly promotes the catalytic activity, with the optimal molar ratio of Ru observed at 1:1. 1.0Cs-Ru/CeO2{100} exhibited superior catalytic activity and durability compared to the others. This study proves that CeO2{100} can improve the electron donation to Ru, which is essential for enhancing N2 re-combinative desorption to elevate the NH3 decomposition activity.

Advances in Blue Energy Fuels: Harvesting Energy from Ocean for Self‐Powered Electrolysis

Abstract70% of the earth's surface is covered by the ocean, and it represents a promising and renewable clean energy reservoir that waits for further exploration. Although hydrogen (H2) boasts a high energy density of 143 MJ kg−1 and environmentally friendly attributes, the widespread commercialization of green H2 production remains a formidable challenge. With huge amounts of water, the ocean presents an opportunity for generating H2 fuel through the process of seawater electrolysis. This review introduces ocean‐driven, self‐powered blue energy conversion devices, including triboelectric nanogenerators (TENGs), magnetoelastic generators (MEGs), and solar cells. They are able to convert renewable energy from the ocean, including water waves, wind, and solar energy, into electricity for on‐site seawater‐splitting and H2 generation. This review systematically reports this compelling approach by introducing the fundamental principles of the devices and showcasing the practical applications. Additionally, aiming to promote future research in the field of sustainable energy, this review also delves into the development of novel ocean energy harvesting systems with high energy conversion efficiency for large‐scale and effective H2 production.

The role of geophysics in geologic hydrogen resources

Abstract Transition to cleaner energy sources is crucial for reducing carbon emissions to zero. Among these new clean energy types, there is a growing awareness of the potential for naturally occurring geologic hydrogen (H2) as a primary energy resource that can be readily introduced into the existing energy supply. It is anticipated that geophysics will play a critical role in such endeavors. There are two major different types of geologic H2. One is natural H2 (referred to as gold H2), which is primarily accumulating naturally in reservoirs in certain geological setting; and the other is stimulated H2 (referred to as orange H2), which is produced artificially from source rocks through chemical and physical stimulations. We will first introduce geophysics in geologic H2 in comparison and contrast to the scenarios of blue and green H2. We will then discuss the significance of geophysics in both natural H2 and stimulated H2 in term of both exploration and monitoring tools. Comparing and contrasting the current geophysical tools in hydrocarbon exploration and production, we envision the innovative geophysical technologies and strategies for geologic H2 resources based on our current understanding of both natural and stimulated geologic hydrogen systems. The strategies for H2 exploration will involve a shift from reservoir- to source rock-centered approaches. Last, we believe that the geophysical methods including integration of multi-geophysics, efficient data acquisition, and machine learning in geologic H2 could be potentially provide sufficient new directions and significant opportunities to pursue research for the next one or two decades.

Direct vs. indirect biogas methanation for liquefied biomethane production: A concept evaluation

Conventional liquefied biomethane (LBM) production plants consist of upgrading and liquefaction processes. Commonly, the captured CO2 during biogas upgrading is emitted into the atmosphere. One alternative, to produce more LBM, is to combine the conventional LBM production plant with the Power-to-Gas concept. Within this context, green H2 produced from renewable electricity can react with the CO2 in the biogas mixture, producing additional CH4. The present study evaluated the feasibility of integrating methanation with conventional LBM production plants. The performance of the proposed process designs was assessed through exergy and cost analysis considering detailed models. The results illustrated that integrated direct biogas methanation was superior to methanation of captured CO2. The integrated scheme with direct biogas methanation increased the LBM production by 52.2 % compared to the conventional LBM production plant but with lower exergy efficiency. It was indicated the feasibility of the integrated scheme through direct biogas methanation was highly dependent on the price of H2. A H2 price of 1.27 USD/kg H2 was required to produce LBM at a similar price as the conventional LBM production plant.

TS-1 zeolite encapsulated Pt clusters with enhanced electronic metal-support interaction of Pt−O(H)−Ti for nearly-zero-carbon-emitting photocatalytic hydrogen production from methanol

Photocatalytic H2 production from methanol is sustainable, yet challenges remain in avoiding carbon-containing gaseous by-products. Titanium silicalite-1 (TS-1) zeolite possesses attractive photocatalytic performance, but lack of modification strategies due to its microporous framework. Herein, we developed a pre-anchoring strategy to confine ultra-small Pt clusters inside TS-1 with ultra-low loading (0.2 mol%), in which Pt were anchored in Ti−OH nests by electronic metal-support interaction (EMSI). The optimal catalyst achieved a remarkable H2 generation rate of 63.2 mmol g–1 h–1 in CH3OH solutions, along with the production of high-value chemical HCHO as the oxidation product with 96.9% selectivity. Investigations reveal that the EMSI between Pt and Ti facilitated the selective decomposition of CH3OH to H2 and HCHO, leading to a nearly zero-carbon-emission process. Accordingly, we propose a light-driven carbon-negative "CO2→CH3OH→H2" route, coupling CO2 utilization and green H2 production with CH3OH as the intermediate, therefore offering a new perspective for "liquid sunshine".

Quantitative Analysis of Green H2 Production Costs: A Comparison between Domestic Developed and Imported Electrolyzers

This study aims to present a quantitative cost analysis of hydrogen utilizing a developed alkaline electrolyzer, a similar-capacity imported alkaline electrolyzer, and a similar-capacity PEM electrolyzer.The research also finds the key parameters that can reduce or increase the production cost. One of the subjected electrolyzers is a locally developed Alkaline Electrolyzer (AE); the other two are similar-capacity imported AE and Polymer Electrolytic Membrane (PEM) electrolyzers. The study uses the Hybrid Optimization of Multiple Energy Resources (HOMER) software for estimating the Levelized Cost of Electricity (LCOE) and the Life Cycle Cost (LCC) method for hydrogen production cost estimation. Results show that the imported electrolyzers have higher production costs due to import duty, fees, and taxes. The estimated cost is 88.4% (AE) and 110.3% (PEM), higher than the locally developed electrolyzer. The economic changes also significantly impact production costs. Government policies can reduce the cost by rescheduling the hydrogen components taxes.

Enhanced ammonia-cracking process via induction heating for green hydrogen: A comprehensive energy, exergy, economic, and environmental (4E) analysis

Ammonia (NH3) is gaining attention as a hydrogen carrier due to its high H2 storage capacity and ease of liquefaction at ambient temperatures. The conventional method of ammonia decomposition is thermal cracking through fossil fuel combustion, resulting in significant carbon dioxide (CO2) emissions. Therefore, developing an eco-friendly and highly efficient ammonia decomposition process is important. This study proposed four high-efficiency processes without carbon emissions by improving the induction-heating-based ammonia decomposition process designed in a previous study. The four proposed processes were designed to utilize the H2 discarded as off-gas of the PSA unit in the existing induction-heating-based ammonia decomposition process. The proposed processes incorporate various unit components, including a proton exchange membrane fuel cell (PEMFC), solid oxide fuel cell (SOFC), burner, and palladium (Pd) membrane. These units were integrated with the PSA outlet to achieve enhanced thermodynamic efficiency compared with the conventional process without carbon emissions. Energy, exergy, economic, and environmental analyses were conducted to assess the feasibility of each case. Thermodynamic analysis revealed that integrating the Pd membrane yields the highest thermal (78.29 %) and exergy (64.02 %) efficiencies. Integrating a PEMFC exhibits the lowest levelized cost of H2 (6.93 USD/kg H2). Finally, When the four proposed processes are operated with renewable energy, clean hydrogen can be produced at 2.45 to 3.21 kgCO2/kgH2 emission levels. The enhanced processes presented in this study can serve as a blueprint for achieving carbon-free green H2 production at on-site H2 refueling stations.

Life cycle assessment of synthetic natural gas production from captured cement’s CO2 and green H2

Research on the environmental benefits of carbon capture and utilization (CCU) in cement production so far, has predominantly emphasized energy efficiency enhancements and CO2 emission reductions at a CCU product level, neglecting broader environmental consequences for the sector. This research broadens this perspective by providing an extensive life cycle assessment (LCA) of a circular Portland cement (CPC) model. Synthesized methane is used as input fuel through green hydrogen and calcium-looping (CaL) post-combustion captured CO2 from cement flue gas. Comparative analysis with ordinary Portland cement (OPC) reveals significant reductions in climate change and fossil resource use environmental impact categories. However, trade-offs are evident in acidification, water use, and minerals and metals resource consumption. The electrolysis system is a critical contributor due to the high electricity demand for hydrogen production, and its environmental impact depends largely on the renewable electricity source. The wind-based electrolysis model yields the most favourable results, followed by mixed (50% solar – 50% wind) and solar scenarios. These findings offer valuable insights for the cement industry, supporting stakeholders decision making on the adoption of sustainable circular production methods.

Deactivation mechanism for water splitting: Recent advances

AbstractHydrogen (H2) has been regarded as a promising alternative to fossil‐fuel energy. Green H2 produced via water electrolysis (WE) powered by renewable energy could achieve a zero‐carbon footprint. Considerable attention has been focused on developing highly active catalysts to facilitate the reaction kinetics and improve the energy efficiency of WE. However, the stability of the electrocatalysts hampers the commercial viability of WE. Few studies have elucidated the origin of catalyst degradation. In this review, we first discuss the WE mechanism, including anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER). Then, we provide strategies used to enhance the stability of electrocatalysts. After that, the deactivation mechanisms of the typical commercialized HER and OER catalysts, including Pt, Ni, RuO2, and IrO2, are summarized. Finally, the influence of fluctuating energy on catalyst degradation is highlighted and in situ characterization methodologies for understanding the dynamic deactivation processes are described.

Electron-Rich Ru Supported on N-Doped Coffee Biochar for Selective Reductive Amination of Furfural to Furfurylamine.

Highly selective synthesis of primary amines from renewable biomass has attracted increasing attention, but it still faces great challenges in chemical industry applications. In this study, an electron-rich Ru catalyst was constructed by doping N into coffee biochar using a one-pot carbonization method (Ru/NCB-600). Ru/NCB-600 showed high catalytic activity and yield for the reductive amination of furfural with green and cheap NH3 and H2. The excellent catalytic performance of Ru/NCB-600 was closely correlated to the formation of electron-rich Ruδ- species (Ruδ--Nxδ+), which endowed Ru/NCB-600 with an enhanced H2 adsorption and activation ability. Ru/NCB-600 showed a high formation rate of 95.6 gfurfurylamine·gRu-1·h-1 and a high yield of furfurylamine (98.6%) at 50 °C. Ru/NCB-600 can also be used for the reductive amination of various carbonyl compounds in good to excellent yield (95.4-99%). This study thus provides a potential pathway for the highly selective reductive amination of carbonyl compounds by regulating the electron density of Ru.

The water footprint of hydrogen production

Hydrogen (H2) is the most promising energy carrier for reducing the carbon emissions of the energy sector, but the impact of its production on water resources remains unclear. Here, we quantify the water footprint (WF) of different H2 production pathways accounting for the WF of the primary energy used in the production process, as well as feedstock and infrastructure water requirements. Results suggest that green H2 obtained from water electrolysis powered by renewable energy has the lowest WF (65 ± 2 m3/TJ for wind and 204 ± 79 m3/TJ for solar) mostly due to the low WF of renewable energy. The WF of blue H2 derived from fossil fuels is significantly higher (369 ± 30 m3/TJ for natural gas and 564 ± 82 m3/TJ for coal) due to high WF of fossil fuels as well as the water required for carbon capture and storage (CCS). H2 produced from nuclear energy and biomass have extremely high WF (741 ± 277 m3/TJ for nuclear and > 50,000 m3/TJ for biomass). Considering global and country-based energy scenarios, where the main H2 colors (green and blue) individually account for 15 % of energy consumption, we find that the use of green H2 could reduce the water demand of the energy sector while blue H2 would generally increase it, except in countries already characterized by high water consumption due to reliance on water-intensive energy sources. At the global level, we find that for every 5 % of H2 energy adoption, the energy sector could have water savings between 1 and 4 % for green H2 and increase water consumption between 1 and 5 % for blue H2. These results highlight the potential and criticalities of H2 within the water-energy nexus.

A new strategy of carbon-energy coupling transfer enhancement by formate on phototrophic green microalga Chlamydomonas reinhardtii

Low efficient CO2 and solar energy transfer in aquatic microalgae cultivation are always challenges and have consumed huge efforts during the last two decades. With the development of solar fuels technologies, formate can come from the reduction of CO2 with green H2. As a water-soluble solar fuel, formate is a good carbon-energy coupling enhancement carrier for biosynthesis. However, formate is also an inhibitor to the electron transfer chain (ETC) in the cell. Based on the chloroplast engineering, a series of Chlamydomonas reinhardtii mutants with chloroplast transit peptide chimeric NADPH-dependent formate dehydrogenase (FDH) were constructed, and these mutants were named as PsFDHs. Results showed that exogenous FDH alleviated the inhibition of formate on the photosynthetic system and promoted the growth, and a win–win result obtained between the natural and artificial photosynthesis: 40 % more carbon from formate was fixed than heterotrophic only, and 62 % increase in dry weight (DW), while no obvious formate consumption was detected in the wide type (WT). The maximum overall biomass productivity was 15.4 mg·L−1·h−1, which was 36 % higher than that of WT. It’s postulated that formate enhanced the carbon and energy transportation close to carbon fixation reaction center, and photosynthesis made up for energy shortages in the conversion of formate to biomass. The results showed the potential of formate in achieving a higher-than-nature artificial-natural hybrid photosynthesis by microalgae, to meet requirements of both the carbon neutralization and protein supply for human nutrients.

Interlinking electronic band properties in catalysts with electrochemical nitrogen reduction performance: a direct influence

Abstract The wordwide energy demands and the surge towards a net-zero sustainable society let the researchers set a goal towards the end of carbon cycle. This has enormously exaggerated the electrocatalytic processes such as water splitting, CO2 capture and reduction and nitrogen reduction reaction (NRR) as a safe and green alternative as these involve the utilization of renewable green power. Interestingly, the NH3 produced from NRR has been realized as a future fuel in terms of safer green H2 storage and transportation. Nevertheless, to scale up the NH3 production electrochemically, a benevolent catalyst needs to be developed. More interestingly, the electronic features of the catalyst that actually contribute to the interaction and binding between the adsorbate and reaction intermediates should be analyzed such that these can be tuned based on our requirements to obtain the desired high-standard goals of NH3 synthesis. The current topical review aims to provide an illustrative understanding on the experimental and theoretical descriptors that are likely to influence the electronic structure of catalysts for NRR. We have widely covered a detailed explanation regarding work function, d-band center and electronic effect on the electronic structures of the catalysts. While summarizing the same, we realized that there are several discrepancies in this field, which have not been discussed and could be misleading for the newcomers in the field. Thus, we have briefed the limitations and diverging explanations and have provided a few directions that could be looked upon to overcome the issues.

Self-powered water-splitting using triboelectric nano-generators for green hydrogen production: Recent advancements and perspective

The discovery of triboelectric nano-generators (TENGs) has resulted in the invention and development of self-powered electronics and devices. TENGs offer numerous benefits including their portability, affordability, and sustainable micro-scale energy harvesting in the realm of self-powered sensors and portable devices. TENGs have the capability to function as an autonomous power source. Integration of TENG with electrochemical processes can facilitate self-powered electrochemistry such as water splitting (or electrolysis) for H2 production, thereby eliminating the requirement for an external power supply. This review primarily centers on the operation and the recent advancements of TENGs in self-powered water-splitting for clean and environment-friendly H2 production utilizing renewable energy sources including wind, wave, and low-scale mechanical energy. The concept of conducting water-splitting without reliance on an external power source holds the potential for significant use in the field of clean and green H2 production with cost advantages, sustainability, and other environmental benefits.

Methodology for Assessing Retrofitted Hydrogen Combustion and Fuel Cell Aircraft Environmental Impacts

Hydrogen (H2) combustion and solid oxide fuel cells (SOFCs) can potentially reduce aviation-produced greenhouse gas emissions compared to kerosene propulsion. This paper outlines a methodology for evaluating performance and emission tradeoffs when retrofitting conventional kerosene-powered aircraft with lower-emission H2 combustion and SOFC hybrid alternatives. The proposed framework presents a constant-range approach for designing liquid hydrogen fuel tanks, considering insulation, sizing, center of gravity, and power constraints. A lifecycle assessment evaluates greenhouse gas emissions and contrail formation effects for carbon footprint mitigation, while a cost analysis examines retrofit implementation consequences. A Cessna Citation 560XLS+ case study shows a 5% mass decrease for H2 combustion and a 0.4% mass decrease for the SOFC hybrid, at the tradeoff of removing three passengers. The lifecycle analysis of green hydrogen in aviation reveals a significant reduction in CO2 emissions for H2 combustion and SOFC systems, except for natural-gas-produced H2 combustion, when compared to Jet-A fuel. However, this environmental benefit is contrasted by an increase in fuel cost per passenger-km for green H2 combustion and a rise for natural-gas-produced H2 SOFC compared to kerosene. The results suggest that retrofitting aircraft with alternative fuels could lower carbon emissions, noting the economic and passenger capacity tradeoffs.

Towards building clean hydrogen supply chain network in Iran for future domestic demand and exports. Part II: 4E analyses of prioritized scenarios

In continuation of the previous part, this paper comprehensively focuses on energy, exergy, exergo-economic, and environmental (4E) analyses of two prioritized clean hydrogen (H2) supply chains pathways. The first scenario relies on domestic demand, involves blue H2 production and storage using steam methane reforming coupled with carbon capture and storage through H2 conversion to hydrogen carriers in liquid form (ammonia and methanol) aligned with the existing infrastructure. The second scenario involves green H2 production from photovoltaic panels as the power source follows by storing H2 in liquid form which is more suitable to export. The findings indicate that the blue H2 system outperforms the green H2 system in terms of energy and exergy, boasting 41.38% and 22.15% compared to 12.16% and 12.75%, respectively. However, when examining economic parameters, the blue H2 system shows a total cost rate of 1976 US$/h, a net profit of $747.2 million (mn) at the end of its lifetime, and a payback period of approximately nine years. Conversely, the green H2 system demonstrates economic indicators of a 125.2 $/h as a total cost rate, $1.26 billion (bn) net profit, and an 8.17 year payback period. Moreover, the production cost rates for blue and green H2 are 1.32 $/kg and 2.55 $/kg, respectively; while the CO2 emissions rate in the blue H2 system is 10.71 kg/s. The green H2 system prevents 19.84 kg/s of CO2 emissions resulted a significant environmental cost reduction of 2.28 $/kg H2. This analysis facilitates a thorough comparison of these two clean H2 production and storage systems, offering insights for policymakers across performance, economic, and environmental dimensions.

Identification of the environmental hotspots of a recycling process - Case study of a Pt PEMFC catalyst closed-loop recycling system evaluated via life cycle assessment methodology

Proton-exchange membrane fuel cell (PEMFC) technology using green H2 as a fuel to produce decarbonized electricity is considered as a promising substitute for fossil fuels. However, its development is impeded by the use of critical raw materials, such as platinum which catalyzes the hydrogen oxidation and oxygen reduction reactions. In this paper, a novel closed-loop system for the re-manufacturing of platinum-based catalyst electrode from recycled material is developed. Three different recycling alternatives are compared using the life cycle assessment (LCA) methodology. The most promising one, which combines the extraction step with an innovative synthesis of recycled Pt/C catalyst, leads to the manufacturing of an electrochemically active Pt/C catalyst with a high recovery efficiency of 96 %. Sensitivity analyses display that the recycling processes significantly relieve the environmental burdens associated with platinum mining and that their efficiencies directly relate to a decrease in environmental impacts.