Shaping the Future of Green Hydrogen Production: Overcoming Conventional Challenges with Molecular Catalysts, Immobilization, and Scalable Electrolyzers

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 1073 - 1096

Published: Jan. 2, 2025

The energy crisis is a daunting global problem that calls for innovative and supportable solutions to ensure future security environmental stability. To counter this uncertainty, accelerating renewable-driven hydrogen production stands as vital option foster carbon-neutral infrastructure. This review conveys an overview of worldwide generation techniques (steam methane reformation, thermochemical, biological, electrolytic), highlighting the key features, indicating pros cons, unraveling potential consequences. Herein, conventional gray cutting-edge green technologies are compared, with focus on sustainable water electrolysis utilizing renewable sources. existing difficulties electrolysis, including usage expensive catalysts in both cathode anode, discussed along possible gateway cost-effective electrocatalysts. focuses three types 3d transition metal-based molecular catalysts─cobaloximes, iron porphyrins, nickel bis-phosphines─for evolution reactions (HER), stressing their strategic synthetic designs, mechanistic routes, catalytic parameters. Despite high activity selectivity, these systems confront stability scalability issues, limiting practical applicability. address this, immobilization into solid matrices studied, simplifying integration membrane electrode assembly (MEA) electrolyzers industrial-scale production. bridge gap between lab-scale investigations commercial implementation, several design components MEA stack examined, such flow patterns scaling methodologies. A comprehensive approach catalyst development deployment ensured by significance Life Cycle Assessment (LCA) Techno-Economic Analysis (TEA) assessing sustainability economic viability. closes call multidisciplinary research innovation improve electrochemical water-splitting technology accelerate enduring economy.

Language: Английский

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Selective PNP Pincer-Ir-Promoted Acceptorless Transformation of Glycerol to Lactic Acid and Hydrogen

Inorganic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 17, 2025

The catalytic transformation of glycerol (GLY) using [(iPr2PNHP)Ir(COD)]Cl [iPr2PNHP = κ3-(iPr2PCH2CH2)2NH] affords hydrogen and lactic acid (LA), trapped as its sodium salt (Na[LA]) with high yield (96%) selectivity (99%) in the presence an equivalent situ generated NaOEt at 140 °C within 4 h. A diminution activity was observed when PNMeP ligand used instead PNHP, or Cl– replaced by [BArF4]−. An Ir to Rh substitution also resulted poor activity. Kinetic studies show a first-order dependence initial rate turnovers on concentrations [(iPr2PNHP)Ir(COD)]Cl, NaOEt, glycerol. outer-sphere mechanism does not explain [(iPr2PNMeP)Ir(COD)]Cl, DFT support inner-sphere mechanism, oxidative addition 14-electron intermediate [(iPr2PNHP)Ir]Cl determined rate-determining step (RDS). kH/kD 2.7 obtained glycerol-d8 shows major contribution from O–H activation RDS. kinetics reaction become favorable (ΔG140⧧ 27.01 kcal/mol) one terminal O–H's is bonded N–H pincer backbone, contrast cases where no bonds are invoked 31.96 possible [(iPr2PNMeP)Ir]Cl 30.36 kcal/mol).

Language: Английский

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Production of Lactic Acid via Catalytic Transfer Dehydrogenation of Glycerol Catalyzed by Base Metal Salt Ferrous Chloride and Its NNN Pincer-Iron Complexes

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(33), P. 15294 - 15310

Published: Aug. 7, 2024

NNN-Bis(imino) pyridine-based pincer-Fe(II) complexes with an expected trigonal bipyramidal (TBP) geometry equilibrated to a rearranged ion pair of octahedral dicationic Fe complex containing two bis(imino)pyridine ligands that are neutralized by tetrahedral dianionic-[FeCl4]2–. Single-crystal X-ray diffraction (SCXRD), high-resolution mass spectrometry (HRMS), and UV–visible (UV–vis) studies suggested the equilibrium was dictated sterics R group on imine N, less-crowded groups tilting bulky ones favoring TBP geometry. Electron paramagnetic resonance (EPR) Evan's magnetic moment measurements indicated were Fe(II) in high-spin state. In solution, over period 7 days, these oxidized mixture low-spin Fe(III) species. These found be highly active toward transformation biodiesel waste glycerol value-added lactic acid (LA). Particularly, (Ph2NNN)FeCl2 (0.1 mol %) gave 91% LA 99% selectivity at 140 °C using 1.2 equiv NaOH. With 0.0001 % (Ph2NNN)FeCl2, very high turnovers (74% LA, 98% selectivity, 740 000 turnover number (TON) 4405 per hour (TOs/h)) obtained after days. EPR species catalyst, few which detected HRMS. Experiments Hg suggestive mostly homogeneous molecular nature catalyst minor contribution from heterogeneous nanoparticles.

Language: Английский

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Temperature-dependent switchable synthesis of imines and amines via coupling of alcohols and amines using pyrrolyl-imine ruthenium catalysts

Journal of Catalysis, Journal Year: 2024, Volume and Issue: unknown, P. 115895 - 115895

Published: Dec. 1, 2024

Language: Английский

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A catalytic approach for the dehydrogenative upgradation of crude glycerol to lactate and hydrogen generation

RSC Advances, Journal Year: 2024, Volume and Issue: 14(50), P. 37082 - 37086

Published: Jan. 1, 2024

An adequate method for the synthesis of lactic acid from a mixture glycerol, ethylene glycol, and methanol industrial waste biomass resources has been demonstrated using Ru catalyst functionalised with proton-responsive ligand framework.

Language: Английский

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