Pub Date : 2026-01-12DOI: 10.1016/j.ijhydene.2026.153452
Josef Marousek , Beata Gavurova , Anna Marouskova
Hydrogen production through dark fermentation is constrained by low yields and slow reaction kinetics, making the produced hydrogen hardly cost-competitive. A series of 6 nanomaterials, including metal oxides, bimetallic nanoparticles, and graphene oxide–based composites, were synthesized and investigated to accelerate hydrogen production during dark fermentation in both free and immobilized cell configurations. Since reactor construction accounts for most of the capital costs and reactor operation dominates the running costs, production kinetics assessed by the modified Gompertz model was chosen as the main strategy for reducing production expenses. Results demonstrated that the alternative of graphene oxide with Ni/Co composite achieved the most significant acceleration of cumulative hydrogen production (2.35 mol H2 mol−1 glucose; reduced lag phase from 6.5 to 4.2 h; and increased maximum production rate by 74 %). It is firstly reported that these nanomaterials enhanced microbial hydrogen production by facilitating electron transfer, decreasing activation energy, and establishing favourable microenvironments for hydrogen-producing microorganisms. Further analysis revealed that bimetallic nanomaterials maintained favourable fermentation conditions with higher pH, more negative oxidation reduction potential and improved metabolic efficiency, which are all prerequisites for eased market implementation.
{"title":"Bimetallic nanoparticles: A promising pathway for reducing hydrogen production costs via dark fermentation","authors":"Josef Marousek , Beata Gavurova , Anna Marouskova","doi":"10.1016/j.ijhydene.2026.153452","DOIUrl":"10.1016/j.ijhydene.2026.153452","url":null,"abstract":"<div><div>Hydrogen production through dark fermentation is constrained by low yields and slow reaction kinetics, making the produced hydrogen hardly cost-competitive. A series of 6 nanomaterials, including metal oxides, bimetallic nanoparticles, and graphene oxide–based composites, were synthesized and investigated to accelerate hydrogen production during dark fermentation in both free and immobilized cell configurations. Since reactor construction accounts for most of the capital costs and reactor operation dominates the running costs, production kinetics assessed by the modified Gompertz model was chosen as the main strategy for reducing production expenses. Results demonstrated that the alternative of graphene oxide with Ni/Co composite achieved the most significant acceleration of cumulative hydrogen production (2.35 mol H<sub>2</sub> mol<sup>−1</sup> glucose; reduced lag phase from 6.5 to 4.2 h; and increased maximum production rate by 74 %). It is firstly reported that these nanomaterials enhanced microbial hydrogen production by facilitating electron transfer, decreasing activation energy, and establishing favourable microenvironments for hydrogen-producing microorganisms. Further analysis revealed that bimetallic nanomaterials maintained favourable fermentation conditions with higher pH, more negative oxidation reduction potential and improved metabolic efficiency, which are all prerequisites for eased market implementation.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153452"},"PeriodicalIF":8.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.ijhydene.2026.153398
Mahmoud Saleh Shahreza , Brandon Harvey , Ibrahim M. Albayati , Eni Oko , Archibong Archibong-Eso , Nick Tucker , Pouriya Niknam , Aliyu Aliyu
Conventional electrodes of water electrolysis face limitations in mass transport and bubble detachment, hindering sustainable hydrogen production. This study investigates the enhancement of hydrogen evolution reaction (HER) efficiency in water electrolysis using 3D-printed macro-patterned 17-4 PH-grade stainless steel electrodes. Leveraging additive manufacturing, stainless steel-based electrodes were fabricated via 3D printing, debinding and sintering, featuring three distinct macro-patterns namely small and large semi-spherical dimples, as well as pyramidal pits. Electrochemical testing using chronoamperometry and efficiency calculations, using KOH electrolyte in a H-cell setup, revealed that patterned electrodes significantly outperformed their flat counterparts. Results show up to a 6.5-percentage point higher voltaic efficiency, and visual observation revealed enhanced bubble detachment. Scanning Electron Micrography (SEM) imaging confirmed inherent microporosity from 3D printing, increasing active surface area. The pyramidal-pit electrode initiated HER at lower voltages, while dimpled designs achieved higher peak current densities. The experimentally measured current densities showed good agreement with the Butler–Volmer model with electrode surface bubble coverage considered. An empirical model developed, shows a strong correlation between the cell’s normalised voltaic efficiency, the non-dimensional current density and the non-dimensional surface area, highlighting the critical role of surface geometry in the efficiency of electrolysis cells. Gold coating reduced ohmic losses but did not consistently improve hydrogen yield. These results add to the growing experimental evidence that 3D-printed macro-patterns are beneficial, and in this case, enabled by an innovative metal additive manufacturing process. HER voltaic efficiency is boosted by at least 5 percentage points for a flat electrode of the same form factor through optimised bubble management and surface area. The study hence underlines the importance of patterned electrodes for industrial green hydrogen production with attendant tangible economic and sustainability benefits.
{"title":"Investigating the voltaic efficiency of 3D-printed macro-patterned electrodes for hydrogen evolution reactions in water electrolysis","authors":"Mahmoud Saleh Shahreza , Brandon Harvey , Ibrahim M. Albayati , Eni Oko , Archibong Archibong-Eso , Nick Tucker , Pouriya Niknam , Aliyu Aliyu","doi":"10.1016/j.ijhydene.2026.153398","DOIUrl":"10.1016/j.ijhydene.2026.153398","url":null,"abstract":"<div><div>Conventional electrodes of water electrolysis face limitations in mass transport and bubble detachment, hindering sustainable hydrogen production. This study investigates the enhancement of hydrogen evolution reaction (HER) efficiency in water electrolysis using 3D-printed macro-patterned 17-4 PH-grade stainless steel electrodes. Leveraging additive manufacturing, stainless steel-based electrodes were fabricated via 3D printing, debinding and sintering, featuring three distinct macro-patterns namely small and large semi-spherical dimples, as well as pyramidal pits. Electrochemical testing using chronoamperometry and efficiency calculations, using KOH electrolyte in a H-cell setup, revealed that patterned electrodes significantly outperformed their flat counterparts. Results show up to a 6.5-percentage point higher voltaic efficiency, and visual observation revealed enhanced bubble detachment. Scanning Electron Micrography (SEM) imaging confirmed inherent microporosity from 3D printing, increasing active surface area. The pyramidal-pit electrode initiated HER at lower voltages, while dimpled designs achieved higher peak current densities. The experimentally measured current densities showed good agreement with the Butler–Volmer model with electrode surface bubble coverage considered. An empirical model developed, shows a strong correlation between the cell’s normalised voltaic efficiency, the non-dimensional current density and the non-dimensional surface area, highlighting the critical role of surface geometry in the efficiency of electrolysis cells. Gold coating reduced ohmic losses but did not consistently improve hydrogen yield. These results add to the growing experimental evidence that 3D-printed macro-patterns are beneficial, and in this case, enabled by an innovative metal additive manufacturing process. HER voltaic efficiency is boosted by at least 5 percentage points for a flat electrode of the same form factor through optimised bubble management and surface area. The study hence underlines the importance of patterned electrodes for industrial green hydrogen production with attendant tangible economic and sustainability benefits.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153398"},"PeriodicalIF":8.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.ijhydene.2025.153261
Yasemin Torlak , Ebru Halvacı , Aysenur Aygun , Fatih Sen
Hydrogen is a key source of clean and sustainable energy for the future, helping to reduce dependence on fossil fuels and develop environmentally friendly alternative energy sources. In this study, Co-POM (K7[CoIIICoII(H2O)W11O39].15H2O), a Keggin-type polyoxometalates (POM) mixed-valence polyoxometalate compound, was synthesized by chemical methods and used as a catalyst for hydrogen production by NaBH4 methanolysis. The crystalline and morphological structures of the catalyst were analyzed using various characterization methods, including XRD, UV-Visible, FT-IR, SEM, and TEM. XRD analysis reveals that Co-POM has a highly crystalline structure, while the FT-IR spectrum confirms that the metal centers and the Co-O bond are stabilized. The characteristic absorption band observed at 270 nm in the UV-Vis spectrum was attributed to the ligand-metal charge transfer originating from the CoIII centers. In addition, the role of polyoxometalate (POM) based catalysts in hydrogen production is increasing in the literature, and the high turnover efficiency of Co-POM in this sector offers different perspectives from other research. During hydrogen production, the effects of temperature, NaBH4 concentration, and catalyst amount on the hydrogen production rate were investigated in detail. The low activation energy (15.75 kJ mol⁻¹) facilitates rapid hydrogen generation, which is reflected in the high TOF value of 657.23 s⁻¹ obtained for the Co-POM catalyst. Control experiments accompanying this study demonstrate that Co-POM is highly efficient in producing hydrogen. It confirms that Co-POM is a strong candidate among innovative hydrogen production catalysts and can be considered as a green alternative in clean energy technologies in the future.
{"title":"Polyoxometalate catalyzed hydrogen production for green energy: A kinetic approach to the high catalytic activity of Co-POM","authors":"Yasemin Torlak , Ebru Halvacı , Aysenur Aygun , Fatih Sen","doi":"10.1016/j.ijhydene.2025.153261","DOIUrl":"10.1016/j.ijhydene.2025.153261","url":null,"abstract":"<div><div>Hydrogen is a key source of clean and sustainable energy for the future, helping to reduce dependence on fossil fuels and develop environmentally friendly alternative energy sources. In this study, Co-POM (K<sub>7</sub>[Co<sup>III</sup>Co<sup>II</sup>(H<sub>2</sub>O)W<sub>11</sub>O<sub>39</sub>].15H<sub>2</sub>O), a Keggin-type polyoxometalates (POM) mixed-valence polyoxometalate compound, was synthesized by chemical methods and used as a catalyst for hydrogen production by NaBH<sub>4</sub> methanolysis. The crystalline and morphological structures of the catalyst were analyzed using various characterization methods, including XRD, UV-Visible, FT-IR, SEM, and TEM. XRD analysis reveals that Co-POM has a highly crystalline structure, while the FT-IR spectrum confirms that the metal centers and the Co-O bond are stabilized. The characteristic absorption band observed at 270 nm in the UV-Vis spectrum was attributed to the ligand-metal charge transfer originating from the Co<sup>III</sup> centers. In addition, the role of polyoxometalate (POM) based catalysts in hydrogen production is increasing in the literature, and the high turnover efficiency of Co-POM in this sector offers different perspectives from other research. During hydrogen production, the effects of temperature, NaBH<sub>4</sub> concentration, and catalyst amount on the hydrogen production rate were investigated in detail. The low activation energy (15.75 kJ mol⁻¹) facilitates rapid hydrogen generation, which is reflected in the high TOF value of 657.23 s⁻¹ obtained for the Co-POM catalyst. Control experiments accompanying this study demonstrate that Co-POM is highly efficient in producing hydrogen. It confirms that Co-POM is a strong candidate among innovative hydrogen production catalysts and can be considered as a green alternative in clean energy technologies in the future.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153261"},"PeriodicalIF":8.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photocatalytic H2 evolution by oxidation photocatalyst is limited in poor solar energy utilization and rapid recombination of photogenerated electron-hole pairs. Herein, a novel ZnIn2S4@Ov-ZnO core-shell S-scheme heterostructure (ZZIS) is rationally fabricated through the in-situ growth of ZnIn2S4 on an oxygen vacancy-rich ZnO spheres. The introduction of oxygen vacancies leads to enhanced photoabsorption. Density functional theory (DFT) calculations and experimental studies confirm the S-scheme charge-transfer mechanism, which concurrently realizes separated charge carriers and sufficient redox ability. Therefore, the optimal 20-ZZIS photocatalyst exhibits high hydrogen evolution rate of 27.85 mmol g−1 h−1 without cocatalyst, which is about 146.5-fold of the pristine ZnO. These findings offer valuable guidance for designing highly efficient and stable inorganic heterojunction photocatalysts for solar energy applications.
{"title":"Oxygen-vacancy-Engineered S-scheme heterojunction for cocatalyst-Free photocatalytic H2 evolution","authors":"Xin Sun, Haipeng Hu, Tong Li, Yingcong Wei, Yuanping Chen, Jing Xu","doi":"10.1016/j.ijhydene.2026.153454","DOIUrl":"10.1016/j.ijhydene.2026.153454","url":null,"abstract":"<div><div>Photocatalytic H<sub>2</sub> evolution by oxidation photocatalyst is limited in poor solar energy utilization and rapid recombination of photogenerated electron-hole pairs. Herein, a novel ZnIn<sub>2</sub>S<sub>4</sub>@Ov-ZnO core-shell S-scheme heterostructure (ZZIS) is rationally fabricated through the in-situ growth of ZnIn<sub>2</sub>S<sub>4</sub> on an oxygen vacancy-rich ZnO spheres. The introduction of oxygen vacancies leads to enhanced photoabsorption. Density functional theory (DFT) calculations and experimental studies confirm the S-scheme charge-transfer mechanism, which concurrently realizes separated charge carriers and sufficient redox ability. Therefore, the optimal 20-ZZIS photocatalyst exhibits high hydrogen evolution rate of 27.85 mmol g<sup>−1</sup> h<sup>−1</sup> without cocatalyst, which is about 146.5-fold of the pristine ZnO. These findings offer valuable guidance for designing highly efficient and stable inorganic heterojunction photocatalysts for solar energy applications.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153454"},"PeriodicalIF":8.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.ijhydene.2026.153382
Lucas Warmuth , Clemens Hofsäß , Thomas A. Zevaco , Dieter Schild , Stephan Pitter , Jörg Sauer
Methanol synthesis’ carbon footprint can be reduced using SynGas feeds from renewable power, but such feeds may strain catalysts due to impurities inherited from its production. Renewable sources include (biogas) pyrolysis, reforming, electrolysis, and shift reactions, whose possible poisons critically affect catalysis for future methanol production. In this work, Cu/ZnO/ZrO2 and Cu/ZnO/ZrO2/SiO2 catalysts were tested under simulated feed conditions containing impurities from hydrogen sources. Since methane impurities and trace oxygen are rarely studied yet highly relevant, solar-powered methane or biogas pyrolysis and alkaline electrolysis were considered as case studies for a wide-rainging, sustainable hydrogen supply. Catalysts were investigated across their lifetime: before and after initial reduction, and during varying times on stream. Results show Cu0 sintering strongly depends on the feed, whereas oxygen-containing feeds promote ZnO crystallization, reducing long-term performance. Incorporating silicon suppresses these effects, enabling more stable catalysts and supporting future use of solar-powered hydrogen feeds.
{"title":"Investigation of methanol catalyst stability in presence of potential green hydrogen impurities","authors":"Lucas Warmuth , Clemens Hofsäß , Thomas A. Zevaco , Dieter Schild , Stephan Pitter , Jörg Sauer","doi":"10.1016/j.ijhydene.2026.153382","DOIUrl":"10.1016/j.ijhydene.2026.153382","url":null,"abstract":"<div><div>Methanol synthesis’ carbon footprint can be reduced using SynGas feeds from renewable power, but such feeds may strain catalysts due to impurities inherited from its production. Renewable sources include (biogas) pyrolysis, reforming, electrolysis, and shift reactions, whose possible poisons critically affect catalysis for future methanol production. In this work, Cu/ZnO/ZrO<sub>2</sub> and Cu/ZnO/ZrO<sub>2</sub>/SiO<sub>2</sub> catalysts were tested under simulated feed conditions containing impurities from hydrogen sources. Since methane impurities and trace oxygen are rarely studied yet highly relevant, solar-powered methane or biogas pyrolysis and alkaline electrolysis were considered as case studies for a wide-rainging, sustainable hydrogen supply. Catalysts were investigated across their lifetime: before and after initial reduction, and during varying times on stream. Results show Cu<sup>0</sup> sintering strongly depends on the feed, whereas oxygen-containing feeds promote ZnO crystallization, reducing long-term performance. Incorporating silicon suppresses these effects, enabling more stable catalysts and supporting future use of solar-powered hydrogen feeds.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153382"},"PeriodicalIF":8.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.ijhydene.2026.153465
Zi-Qiang Luo , Da-Kang Xiong , Ya Hu , Tao Peng , Tao Zou
Chitosan derived hierarchical porous materials (CDHPM) were successfully prepared using chitosan as a ‘green’ carbon source and potassium permanganate as a pore-making agent through a simple pyrolytic synthesis. CDHPM were used as carriers for Pt-based catalysts and tested for their electrocatalytic performance oxygen reduction reaction (ORR) in alkaline electrolyte. The prepared CDHPM can effectively optimize the electrocatalytic performance of Pt-based catalysts due to their large specific surface area, abundant oxygen-containing functional groups, and defect sites. Compared with the commercial catalyst Pt/C (20 % Pt content), Pt/CDHPM (5.75 % Pt content) has higher catalytic activity, durability, and methanol resistance. In conclusion, this study provides an effective strategy for the synthesis of ORR catalysts with high-performance and high-stability, which paves a new way for the development of advanced fuel cell catalysts.
{"title":"Pt nanoparticles loaded chitosan derived hierarchically porous materials as efficient catalysts for oxygen reduction reaction","authors":"Zi-Qiang Luo , Da-Kang Xiong , Ya Hu , Tao Peng , Tao Zou","doi":"10.1016/j.ijhydene.2026.153465","DOIUrl":"10.1016/j.ijhydene.2026.153465","url":null,"abstract":"<div><div>Chitosan derived hierarchical porous materials (CDHPM) were successfully prepared using chitosan as a ‘green’ carbon source and potassium permanganate as a pore-making agent through a simple pyrolytic synthesis. CDHPM were used as carriers for Pt-based catalysts and tested for their electrocatalytic performance oxygen reduction reaction (ORR) in alkaline electrolyte. The prepared CDHPM can effectively optimize the electrocatalytic performance of Pt-based catalysts due to their large specific surface area, abundant oxygen-containing functional groups, and defect sites. Compared with the commercial catalyst Pt/C (20 % Pt content), Pt/CDHPM (5.75 % Pt content) has higher catalytic activity, durability, and methanol resistance. In conclusion, this study provides an effective strategy for the synthesis of ORR catalysts with high-performance and high-stability, which paves a new way for the development of advanced fuel cell catalysts.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153465"},"PeriodicalIF":8.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photocatalytic hydrogen evolution represents a pivotal pathway for clean energy conversion. However, the development of high-performance photocatalysts is often constrained by unsustainable synthesis methods and, more fundamentally, by the limited ability to precisely control the interfacial structure for directed charge transport. Herein, we develop a green synthesis strategy to fabricate a polyaromatic carbon layer-encapsulated TiO2 heterojunction bridged by interfacial Ti-O-C bonds. This is achieved through the controlled calcination of biomass-derived xylose, yielding carbonaceous layers with well-defined sp2-hybridized configurations. The optimized Pt-2X-T300 photocatalyst demonstrates a remarkable hydrogen evolution rate of 8570.9 μmol g−1 h−1 under visible light, which is approximately 1993 times higher than that of the Pt-T300 benchmark. The enhanced performance is attributed to efficient charge carrier separation driven by the interfacial Ti-O-C bond, which optimizes the band alignment between TiO2 and sp2-carbon layers. Mechanistic studies verify that the atomic-level interface establishes a rapid electron transfer pathway, yielding an apparent quantum yield of ∼8.4 % at 420 nm. This work not only establishes a methodology for converting carbohydrates into tailored carbon nanostructures but also develops a novel Ti-O-C bridged TiO2@carbon heterojunction architecture, offering a novel approach for designing high-efficiency solar-driven hydrogen production systems.
{"title":"Engineering TiO2@polyaromatic carbon heterojunctions via biomass-derived precursors for efficient visible light photocatalytic H2 evolution","authors":"Jingyun Mao, Chengjing Lu, Qingrong Qian, Qinghua Chen, Hun Xue, Fangyuan Cheng","doi":"10.1016/j.ijhydene.2026.153447","DOIUrl":"10.1016/j.ijhydene.2026.153447","url":null,"abstract":"<div><div>Photocatalytic hydrogen evolution represents a pivotal pathway for clean energy conversion. However, the development of high-performance photocatalysts is often constrained by unsustainable synthesis methods and, more fundamentally, by the limited ability to precisely control the interfacial structure for directed charge transport. Herein, we develop a green synthesis strategy to fabricate a polyaromatic carbon layer-encapsulated TiO<sub>2</sub> heterojunction bridged by interfacial Ti-O-C bonds. This is achieved through the controlled calcination of biomass-derived xylose, yielding carbonaceous layers with well-defined sp<sup>2</sup>-hybridized configurations. The optimized Pt-2X-T300 photocatalyst demonstrates a remarkable hydrogen evolution rate of 8570.9 μmol g<sup>−1</sup> h<sup>−1</sup> under visible light, which is approximately 1993 times higher than that of the Pt-T300 benchmark. The enhanced performance is attributed to efficient charge carrier separation driven by the interfacial Ti-O-C bond, which optimizes the band alignment between TiO<sub>2</sub> and sp<sup>2</sup>-carbon layers. Mechanistic studies verify that the atomic-level interface establishes a rapid electron transfer pathway, yielding an apparent quantum yield of ∼8.4 % at 420 nm. This work not only establishes a methodology for converting carbohydrates into tailored carbon nanostructures but also develops a novel Ti-O-C bridged TiO<sub>2</sub>@carbon heterojunction architecture, offering a novel approach for designing high-efficiency solar-driven hydrogen production systems.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153447"},"PeriodicalIF":8.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.ijhydene.2026.153430
Amir Mardani , Hanyoung Kim , Sechul Oh , Kyung Chun Kim , Xi Xia , Fei Qi
This paper presents an experimental investigation of a non-premixed gas turbine model combustor designed for ammonia fuel or blended compositions within an atmospheric setting. The fuels considered include methane, hydrogen, ammonia, or their mixtures. The study focuses on flame stability in terms of equivalence ratio of Lean Blowout (LBO) for various fuel mixtures, natural flame chemiluminescence, and emissions, with a particular emphasis on hydrogen and ammonia blends. Initial assessments aim to enhance ammonia reactivity through methane or hydrogen, ultimately recommending hydrogen. The results show that the burner exhibits an LBO equivalence ratio range below 0.58 for methane, decreasing further to below 0.3 for hydrogen-ammonia fuel blends. The study indicates that complete combustion (Zero ppmv of ammonia and hydrogen in exhaust gas) of ammonia/H2 with low NOx levels (<40 ppmv) under lean conditions is achievable. To address NOx and N2O emissions, variations in fuel H2 content, preheating, and dilution offer control mechanisms for both of them. Increasing hydrogen content and preheating elevate NOx levels and, conversely, reduce N2O emissions. Air dilution decreases NOx levels while increasing N2O emissions. The data suggest that a hydrogen content of 16–19 % (by volume) presents a trade-off between NOx and N2O emissions, maintaining levels below 500 ppmv. Furthermore, higher levels of preheating and dilution enable the transition to flame transparency and uniformity in the OH field, while exhaust gas composition measurements ensure complete combustion (without unburned fuel) and NOx levels below 40 ppmv, resembling the MILD (Moderate or Intense Low-oxygen Dilution) combustion regime.
{"title":"Experimental investigation of an ammonia-hydrogen-methane non-premixed high swirl model combustor for preheated and diluted air regime","authors":"Amir Mardani , Hanyoung Kim , Sechul Oh , Kyung Chun Kim , Xi Xia , Fei Qi","doi":"10.1016/j.ijhydene.2026.153430","DOIUrl":"10.1016/j.ijhydene.2026.153430","url":null,"abstract":"<div><div>This paper presents an experimental investigation of a non-premixed gas turbine model combustor designed for ammonia fuel or blended compositions within an atmospheric setting. The fuels considered include methane, hydrogen, ammonia, or their mixtures. The study focuses on flame stability in terms of equivalence ratio of Lean Blowout (LBO) for various fuel mixtures, natural flame chemiluminescence, and emissions, with a particular emphasis on hydrogen and ammonia blends. Initial assessments aim to enhance ammonia reactivity through methane or hydrogen, ultimately recommending hydrogen. The results show that the burner exhibits an LBO equivalence ratio range below 0.58 for methane, decreasing further to below 0.3 for hydrogen-ammonia fuel blends. The study indicates that complete combustion (Zero ppmv of ammonia and hydrogen in exhaust gas) of ammonia/H<sub>2</sub> with low NO<sub>x</sub> levels (<40 ppmv) under lean conditions is achievable. To address NO<sub>x</sub> and N<sub>2</sub>O emissions, variations in fuel H<sub>2</sub> content, preheating, and dilution offer control mechanisms for both of them. Increasing hydrogen content and preheating elevate NO<sub>x</sub> levels and, conversely, reduce N<sub>2</sub>O emissions. Air dilution decreases NO<sub>x</sub> levels while increasing N<sub>2</sub>O emissions. The data suggest that a hydrogen content of 16–19 % (by volume) presents a trade-off between NO<sub>x</sub> and N<sub>2</sub>O emissions, maintaining levels below 500 ppmv. Furthermore, higher levels of preheating and dilution enable the transition to flame transparency and uniformity in the OH field, while exhaust gas composition measurements ensure complete combustion (without unburned fuel) and NO<sub>x</sub> levels below 40 ppmv, resembling the MILD (Moderate or Intense Low-oxygen Dilution) combustion regime.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153430"},"PeriodicalIF":8.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In proton exchange membrane water electrolyzers (PEMWEs), performance limitations and high catalyst costs are primarily associated with mass transport bottlenecks and suboptimal anode catalyst layer structures. This study presents a validated two-dimensional model that incorporates key mass transport and reaction phenomena, including oxygen evolution and two-phase flow dynamics, to investigate and optimize anode catalyst layer performance. Using topology optimization (TO) based on the density method, we identified electrode structures that significantly enhance electrochemical activity and catalyst utilization. The fully optimized catalyst layer design achieved up to a 65 % improvement in overall performance and a 58 % improvement in catalyst utilization, while a physically fabricated demonstration structure, inspired by the optimized design, achieved a 44 % improvement in catalyst utilization. Comparative analysis of simulated and experimental results highlighted improvements in mass transport, reactant distribution, and oxygen removal as the primary mechanisms underlying the performance gains. This work demonstrates the potential of to reduce catalyst usage while enhancing PEMWE efficiency and provides a practical framework for translating computationally optimized designs into manufacturable electrode structures, advancing the development of high-performance and cost-effective PEMWE systems.
{"title":"Integrating two-phase modeling and topology optimization for high-performance proton exchange membrane water electrolyzer electrodes","authors":"Peerapat Orncompa , Phonlakrit Passakornjaras , Takahiro Suzuki , Shohji Tsushima , Patcharawat Charoen-amornkitt","doi":"10.1016/j.ijhydene.2026.153453","DOIUrl":"10.1016/j.ijhydene.2026.153453","url":null,"abstract":"<div><div>In proton exchange membrane water electrolyzers (PEMWEs), performance limitations and high catalyst costs are primarily associated with mass transport bottlenecks and suboptimal anode catalyst layer structures. This study presents a validated two-dimensional model that incorporates key mass transport and reaction phenomena, including oxygen evolution and two-phase flow dynamics, to investigate and optimize anode catalyst layer performance. Using topology optimization (TO) based on the density method, we identified electrode structures that significantly enhance electrochemical activity and catalyst utilization. The fully optimized catalyst layer design achieved up to a 65 % improvement in overall performance and a 58 % improvement in catalyst utilization, while a physically fabricated demonstration structure, inspired by the optimized design, achieved a 44 % improvement in catalyst utilization. Comparative analysis of simulated and experimental results highlighted improvements in mass transport, reactant distribution, and oxygen removal as the primary mechanisms underlying the performance gains. This work demonstrates the potential of to reduce catalyst usage while enhancing PEMWE efficiency and provides a practical framework for translating computationally optimized designs into manufacturable electrode structures, advancing the development of high-performance and cost-effective PEMWE systems.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153453"},"PeriodicalIF":8.3,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-11DOI: 10.1016/j.ijhydene.2026.153479
Qiang Gao , Yang Hu , Hongyun Hu , Chan Zou , Xinhong Yuan , Xian Li , Hong Yao
Hydrogen production from organic solid waste via pyrolysis is a low-carbon and promising way. However, low hydrogen conversion capability limited by heat transfer and catalysis hinders highly efficient utilization of solid waste pyrolysis gases. In this study, the selected NaOH–Na2CO3 binary salt was introduced to optimize H2 production during thermal treatment of waste tires, and the characteristics of hydrogen distribution and its generation mechanism were investigated. The results demonstrated that molten salt treatment increased H2 yield by 17 times compared to conventional pyrolysis at 575 °C, and H2 share in pyrolysis gas exceeded 72 vol%. An increase in temperature also increased hydrogen yield under molten salt conditions, and the hydrogen yield rose to 14.3 mmol/g-feedstock at 575 °C. Additionally, molten salt exhibited large H2 production with over 2 mmol/g-feedstock for large particle feedstocks with a particle size of 10 mm. According to oil analysis and rubber pure substance validation, molten salt promoted the Diels-Alder reaction and aromatization of butadiene monomers from the decomposition of cis-butadiene and styrene-butadiene rubber, leading to the release of hydrogen and increasing the H2 concentration level in the pyrolysis gas. This study provides a technical practice for the hydrogen production from solid waste.
{"title":"Optimizing H2 production of waste tires pyrolysis gas using NaOH–Na2CO3 binary salt","authors":"Qiang Gao , Yang Hu , Hongyun Hu , Chan Zou , Xinhong Yuan , Xian Li , Hong Yao","doi":"10.1016/j.ijhydene.2026.153479","DOIUrl":"10.1016/j.ijhydene.2026.153479","url":null,"abstract":"<div><div>Hydrogen production from organic solid waste via pyrolysis is a low-carbon and promising way. However, low hydrogen conversion capability limited by heat transfer and catalysis hinders highly efficient utilization of solid waste pyrolysis gases. In this study, the selected NaOH–Na<sub>2</sub>CO<sub>3</sub> binary salt was introduced to optimize H<sub>2</sub> production during thermal treatment of waste tires, and the characteristics of hydrogen distribution and its generation mechanism were investigated. The results demonstrated that molten salt treatment increased H<sub>2</sub> yield by 17 times compared to conventional pyrolysis at 575 °C, and H<sub>2</sub> share in pyrolysis gas exceeded 72 vol%. An increase in temperature also increased hydrogen yield under molten salt conditions, and the hydrogen yield rose to 14.3 mmol/g-feedstock at 575 °C. Additionally, molten salt exhibited large H<sub>2</sub> production with over 2 mmol/g-feedstock for large particle feedstocks with a particle size of 10 mm. According to oil analysis and rubber pure substance validation, molten salt promoted the Diels-Alder reaction and aromatization of butadiene monomers from the decomposition of <em>cis</em>-butadiene and styrene-butadiene rubber, leading to the release of hydrogen and increasing the H<sub>2</sub> concentration level in the pyrolysis gas. This study provides a technical practice for the hydrogen production from solid waste.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"207 ","pages":"Article 153479"},"PeriodicalIF":8.3,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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