The rational design and synthesis of single-layer noble metal clusters directly anchored on support materials represent a long-standing challenge in catalysis science. This study presents a breakthrough through the successful fabrication of well-defined single-layer platinum (Pt-SL) clusters anchored on ultrathin TiO₂ nanosheets, marking a new frontier in electrocatalysis. The structural evolution from isolated single Pt atoms (Pt-SA) to self-assembled single-layer Pt clusters is systematically investigated using advanced characterization techniques. Notably, the Pt atoms within the Pt-SL/TiO₂ structure exhibit a unique electronic configuration characterized by covalent Pt–Pt bonds surrounded by abundant unpaired electrons. This distinctive bonding nature arises from the formation of valence-type bonds rather than metallic bonding, which is observed in multilayer Pt or nanoparticle systems. As a result, the Pt-SL/TiO₂ catalyst demonstrates significantly enhanced electrochemical performance across multiple reactions—including hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and alcohol oxidation—outperforming both Pt-SA/TiO₂ and conventional Pt nanoparticles (Pt-NPs/TiO₂). The superior activity stems from the synergistic combination of maximized atom utilization, continuous active sites due to the pseudo-2D morphology, and unsaturated coordination environments that facilitate multi-electron transfer processes. These findings establish single-layer Pt clusters as a highly efficient and promising class of electrocatalysts, offering a viable pathway toward reducing precious metal usage without sacrificing catalytic efficiency.
High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), extended X-ray absorption fine structure (EXAFS), and X-ray photoelectron spectroscopy (XPS) were employed to monitor the formation process and structural evolution of Pt-SL/TiO₂ during thermal reduction at varying temperatures. At 100 °C, isolated Pt atoms dispersed on TiO₂ (Pt-SA/TiO₂) are formed. Upon increasing temperature to 150–200 °C, partial self-assembly into small single-layer clusters occurs, leading to coexistence of Pt-SA and Pt-SL. At 300 °C, nearly complete transformation into uniform single-layer Pt clusters is achieved, yielding the optimal Pt-SL/TiO₂ sample. Further heating to 400 °C triggers sintering and aggregation into Pt nanoparticles due to increased atomic mobility. EXAFS analysis confirms the presence of weak but distinct Pt–Pt interactions at ~2.76 Å in Pt-SL/TiO₂, shorter than the metallic bond length (~2.81 Å) in bulk Pt, indicating valence bonding. XPS results reveal the coexistence of Pt⁰, Pt²⁺, and Pt⁴⁺ states in Pt-SL/TiO₂, confirming an unsaturated electronic environment with high reactivity. DFT calculations further validate that the Pt–Pt valence bonds enhance electron delocalization and promote favorable adsorption/desorption kinetics for key intermediates such as H*, OH*, and O*.Langerin Antibody Biological Activity
Electrochemical evaluations demonstrate outstanding HER performance: Pt-SL/TiO₂ exhibits a low overpotential of 170 mV at 5 mA cm⁻² and a Tafel slope of only 79 mV dec⁻¹—significantly lower than Pt-SA/TiO₂ (410 mV dec⁻¹), Pt-bilayer, and Pt-NPs/TiO₂.CX3CR1 Antibody site Accelerated durability tests (5000 cycles) show minimal degradation, with negligible morphological changes confirmed by post-cycling HAADF-STEM.PMID:34748226 In ORR, Pt-SL/TiO₂ delivers a mass activity of 4.9 mA μg⁻¹Pt at 0.8 V vs. RHE—nearly three times higher than Pt-SA/TiO₂—and maintains stable performance after 20,000 cycles. The four-electron pathway dominates, minimizing peroxide formation. Similarly, Pt-SL/TiO₂ excels in OER and alcohol oxidation reactions, where multiple active sites are essential. This versatility underscores its potential for use in fuel cells, water electrolyzers, and other energy conversion devices. In summary, this work pioneers a new class of single-layer atomic clusters that combine atomic-scale precision with functional continuity, enabling unprecedented catalytic efficiency and stability.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