🔬 Single-atom catalysts (SACs) have garnered attention for their potential in improving the efficiency and durability of catalytic reactions. This study focuses on investigating the oxygen evolution reaction (OER) on a Pt single-atom catalyst supported on indium tin oxide (ITO). The researchers aim to understand how the OER works by studying how the catalyst and reactants interact in real-life conditions.
Summary
- 🔹 Single-atom catalysts (SACs) have high catalytic activity and selectivity due to their maximized atom utilization efficiency.
- 🔹 SACs have been applied to various reactions, including CO oxidation, hydrogenation, dehydrogenation, and electrocatalytic reactions.
- 🔹 SACs offer the potential for optimal metal utilization and cost, particularly for expensive noble metal catalysts.
- 🔹 SACs can exhibit unique reaction pathways and are suitable for molecular-level understanding using analytical tools and computational modeling. 🔹 The oxygen evolution reaction (OER) is a crucial step in electrocatalytic water splitting and producing hydrogen sustainably.
- 🔹 SACs have received attention for their potential to enhance the efficiency and durability of OER catalysts.
- 🔹 The study investigates the OER on a Pt single-atom catalyst supported on indium tin oxide (ITO) and explores the active site and reaction mechanism.
🔹 Single-atom catalysts (SACs) have emerged as promising catalysts due to their high atom utilization efficiency, which leads to enhanced catalytic activity and selectivity. They have been widely used in various reactions, including CO oxidation, hydrogenation, dehydrogenation, and electrocatalytic reactions. SACs, such as those made of noble metals like Ir, Pd, and Pt, offer the advantage of maximum dispersion and exposure of metal atoms, potentially leading to improved utilization and cost efficiency compared to nanoparticle catalysts. Additionally, SACs allow for a deeper understanding of the active-site structure and reaction mechanisms through the utilization of element-specific analytical techniques, in situ/operando characterization, and computational modeling.
🔹 The oxygen evolution reaction (OER) is a critical step in the electrocatalytic water-splitting process, which is a promising method for environmentally friendly hydrogen production. However, the high overpotential required for OER in acidic conditions has limited the efficiency of acidic water electrolysis. SACs have attracted attention as potential catalysts for improving OER efficiency and durability due to their high fraction of exposed active sites, durability, and stability in aggressive environments.
🔹 The study specifically focuses on investigating the OER on a Pt single-atom catalyst supported on indium tin oxide (ITO). The OER involves the production of oxygen gas from water through a four-electron transfer process. Researchers use computer methods to identify the most stable locations for placing a single Pt atom and analyze how reactions occur under different electrochemical conditions.The goal is to understand the active site of the catalyst and the interaction with hydroxyl and oxygen species during the OER.
🔹 To determine the active site of the catalyst and the nature of its interaction with reactants, in situ techniques like operando X-ray absorption spectroscopy (XAS) are crucial. These techniques provide insights into the dynamic electronic and local environments of SACs and help identify the nature of their active sites. Previous studies using operando XAS have revealed the formation of stable Pt oxide during the oxygen reduction reaction (ORR) on Pt single atoms supported on graphitic carbon nitride.
This study aimed to gain a molecular-level understanding of the OER mechanism on Pt single atoms supported on ITO. The researchers used computational methods to explore the behavior of the catalyst under realistic reaction conditions, considering the presence of water molecules, hydroxyl groups, and oxygen adsorbates.
The study involved optimizing the position of the Pt single atom and analyzing the movement of hydroxyls and water already present on the ITO surface. The researchers investigated the overpotential of the OER and identified the rate-determining step in the catalytic cycle. The catalyst used to simulate the OER mechanism may not have the correct active center. It is important to consider the functional groups generated during reaction conditions.
Understanding the active site of the catalyst and its interaction with reactants is crucial, particularly for SACs where the metal atom is highly exposed. In situ techniques like operando XAS can provide valuable information about the dynamic electronic and local environments of SACs, helping identify the nature of their active sites.
The researchers also utilized the grand canonical basin hopping method to determine the optimum coverage of hydroxyl groups, oxygen atoms, and hydroperoxo species around the Pt single atoms on ITO at different electrochemical potentials. By exploring the free energy surface, they aimed to identify the most stable adsorption sites and optimize the catalyst’s performance.
