The hydrogen evolution reaction (HER) is a pivotal cathode process in electrochemical water splitting, yet the development of efficient catalysts remains a significant challenge. This study presents comprehensive density functional theory (DFT) calculations to investigate the intrinsic HER behaviors of a series of ruthenium dichalcogenide crystals—RuX₂ (X = S, Se, Te). A scalable synthesis strategy was developed to uniformly deposit RuX₂ nanoparticles onto carbon nanotubes (CNTs), enabling systematic evaluation of their electrocatalytic performance. Theoretical predictions were validated experimentally, revealing exceptional HER activity across different pH environments. Notably, marcasite-type RuTe₂ (RuTe₂-M) exhibits Pt-like catalytic efficiency in acidic media with an overpotential of only 35.7 mV at 10 mA cm⁻², while pyrite-type RuSe₂ demonstrates outstanding performance in alkaline conditions, achieving 29.5 mV at the same current density—surpassing commercial Pt/C. Furthermore, prototype proton exchange membrane (PEM) and anion exchange membrane (AEM) electrolyzers were assembled using RuTe₂-M and RuSe₂ as cathode catalysts, respectively. These devices exhibited high single-cell performance, confirming their viability for practical hydrogen production. This work establishes a foundation for designing next-generation transition metal dichalcogenide catalysts with superior activity and stability for sustainable energy applications.
The increasing global demand for clean energy and rising greenhouse gas emissions have driven research into renewable power technologies. However, intermittent sources like solar, wind, and tidal energy require effective storage solutions. Power-to-gas systems, particularly hydrogen production via water electrolysis, offer a promising pathway. Hydrogen can be stored under pressure and used in chemical industries or fuel cells, providing a flexible energy carrier. Traditional liquid electrolyte-based electrolyzers suffer from issues such as leakage, CO₂ sensitivity, and limited durability. In contrast, advanced PEM and AEM electrolyzers offer higher purity H₂ output, compact design, and enhanced safety. Within these systems, the cathodic HER is a critical step determining overall efficiency. Platinum remains the benchmark HER catalyst in acidic media due to its optimal hydrogen binding energy; however, its scarcity and cost hinder widespread use. In alkaline environments, Pt’s performance drops dramatically—by two to three orders of magnitude—limiting its application.IGF2BP3 Antibody custom synthesis Alternative materials such as pyrite-phase MX₂ (M = Fe, Co, Ni; X = S, Se, Te) have shown moderate HER activity, but their performance lags behind Pt, especially in acidic conditions. Recent studies suggest that both metal sites and chalcogenide atoms contribute to catalytic activity by facilitating rapid proton and electron transfer, though challenges remain in achieving sufficient activity and stability.
Ruthenium-based catalysts have emerged as viable alternatives due to their Pt-like hydrogen binding strength and excellent corrosion resistance in both acidic and alkaline media. Moreover, Ru is the most cost-effective platinum-group element. Despite this potential, ruthenium dichalcogenides (RuX₂) have received minimal attention in HER research. Previous attempts to synthesize RuS₂ and RuSe₂ yielded large particles with poor dispersion on supports, limiting their catalytic effectiveness. No reports exist on RuSe₂’s HER performance, and RuTe₂’s dual-phase structure (pyrite and marcasite) has been underexplored, particularly regarding catalytic activity. Existing synthesis methods rely on complex templates like telluride nanorods, which introduce inactive elemental Te and complicate processing. To date, no theoretical analysis has been conducted on the HER properties of RuX₂ materials, underscoring the need for a combined theoretical and experimental investigation. This study addresses that gap through DFT simulations of RuS₂, RuSe₂, RuTe₂ (pyrite), and RuTe₂-M (marcasite), focusing on H, H₂O, and OH⁻ adsorption energies, as well as water dissociation barriers. Based on these insights, a simple, scalable method was developed to synthesize RuX₂/CNT composites. Electrochemical testing confirmed remarkable HER performance: RuTe₂-M delivered Pt-like activity in acid, while RuSe₂ outperformed Pt/C in base. Finally, functional PEM and AEM electrolyzers were constructed, demonstrating high efficiency and scalability—highlighting the strong practical potential of these materials.
Synthesis and structural characterization revealed that RuX₂ phases could be precisely controlled by adjusting annealing temperature. XRD patterns confirmed the formation of cubic RuS₂, RuSe₂, and pyrite-type RuTe₂ at 700 °C, while increasing temperature to 850 °C induced phase transformation to marcasite-type RuTe₂-M. TEM imaging showed uniform nanoparticle distribution on CNTs, with average sizes ranging from 3.3 nm (RuS₂) to 12.8 nm (RuTe₂). High-resolution images revealed lattice fringes corresponding to specific crystal planes, confirming crystallinity. XPS analysis indicated electron transfer from Ru to S and Se, consistent with DFT predictions. The presence of surface oxides (e.g., TeO₂) was observed, suggesting partial oxidation during air exposure.PRL Antibody Cancer Nevertheless, post-HER testing showed minimal changes in valence states, indicating good stability.PMID:35264097 BET surface area measurements ranged from 118.5 to 173.1 m² g⁻¹, supporting effective mass transport. The CNT support played multiple roles: enhancing Ru anchoring, enabling fast electron conduction, and promoting reactant access and gas release.
Electrochemical evaluations in both acidic (0.5 M H₂SO₄) and alkaline (1.0 M KOH) media demonstrated superior HER performance. In acid, RuTe₂-M required just 35.7 mV overpotential at 10 mA cm⁻², with a Tafel slope of 46.6 mV dec⁻¹, indicating a Volmer–Heyrovsky mechanism. At 100 mA cm⁻², it maintained excellent activity (92.3 mV), comparable to Pt/C. In alkaline medium, RuSe₂ achieved 29.5 mV overpotential and a remarkably low Tafel slope of 39.2 mV dec⁻¹—indicating efficient Volmer–Tafel kinetics—and surpassed Pt/C in both overpotential and exchange current density (1.79 vs. 1.70 mA cm⁻²). EIS results confirmed the lowest charge transfer resistance for RuTe₂-M (acid) and RuSe₂ (alkaline), aligning with their superior activity. Long-term stability tests showed negligible degradation after 2000 CV cycles and 15 hours of chronoamperometry, with XRD and XPS confirming structural and chemical integrity post-testing.
Single-cell electrolyzer experiments further validated the practical applicability. The RuTe₂-M-based PEM electrolyzer operated efficiently at 80 °C, delivering 0.68 A cm⁻² at 1.8 V and 0.25 A cm⁻² at 1.6 V. Similarly, the RuSe₂-based AEM electrolyzer reached 0.73 A cm⁻² at 1.8 V at room temperature, increasing to 1.78 A cm⁻² at 80 °C under 1.8 V. These results significantly exceeded those of Pt/C-based counterparts, especially in alkaline conditions where Pt/C performance deteriorated. Nyquist plots confirmed reduced charge transfer resistance at elevated temperatures, enhancing overall efficiency. This work demonstrates that tailored RuX₂ phases, when integrated with conductive CNT supports, represent a highly promising class of non-precious electrocatalysts for industrial-scale hydrogen production.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
