Surface Extraction Process During Initial Oxidation of Pt(111): Effect of Hydrophilic/Hydrophobic Cations in Alkaline Media.

The surface oxidation states of the metal electrodes affect the activity, selectivity, and stability of the electrocatalysts. Oxide formation and reduction on such electrodes must be comprehensively understood to achieve next-generation electrocatalysts with outstanding performance and stability. Herein, the initial electrochemical oxidation of Pt(111) in alkaline media containing hydrophilic and hydrophobic cations is investigated by X-ray crystal truncation rod (CTR) scattering, infrared (IR) spectroscopy, and nanoparticle-based surface-enhanced Raman spectroscopy (SERS).

Cations Determine the Mechanism and Selectivity of Alkaline Oxygen Reduction Reaction on Pt(111).

The proton-coupled electron transfer (PCET) mechanism of the oxygen reduction reaction (ORR) is a long-standing enigma in electrocatalysis. Despite decades of research, the factors determining the microscopic mechanism of ORR-PCET as a function of pH, electrolyte, and electrode potential remain unresolved, even on the prototypical Pt(111) surface. Herein, we integrate advanced experiments, simulations, and theory to uncover the mechanism of the cation effects on alkaline ORR on well-defined Pt(111).

Tailoring the active site for the oxygen evolution reaction on a Pt electrode.

Highly active electrocatalysts for the oxygen evolution reaction (OER) are essential to improve the efficiency of water electrolysis. The properties of OER active sites on single-crystal Pt electrodes were examined herein. The OER is markedly enhanced by repeated oxidative and reductive potential cycles on the Pt(111) surface.

Fast-Decoding Algorithm for Electrode Processes at Electrified Interfaces by Mean-Field Kinetic Model and Bayesian Data Assimilation: An Active-Data-Mining Approach for the Efficient Search and Discovery of Electrocatalysts.

The microscopic origins of the activity and selectivity of electrocatalysts has been a long-lasting enigma since the 19th century. By applying an active-data-mining approach, employing a mean-field kinetic model and a statistical approach of Bayesian data assimilation, we demonstrate here a fast decoding to extract key properties in the kinetics of complicated electrode processes from current-potential profiles in experimental and literary data. As the proof-of-concept, kinetic parameters on the four-electron oxygen reduction reaction in the 0.

Effect of Hydrophobic Cations on the Inhibitors for the Oxygen Reduction Reaction on Anions and Ionomers Adsorbed on Single-Crystal Pt Electrodes.

Weakening of the poisoning by the specifically adsorbed anions assists in developing next-generation electrocatalysts for use in low-temperature fuel cells. In this study, we evaluated how hydrophobic cations with different alkyl chain lengths affect the oxygen reduction reaction (ORR) activities on the single-crystal Pt surfaces in contact with sulfuric acid solution and Nafion ionomers. Interfacial tetraalkylammonium cations with longer alkyl chains activated the ORR on the Pt(111) surface.

Advances and challenges for experiment and theory for multi-electron multi-proton transfer at electrified solid-liquid interfaces.

Multi-electron, multi-proton transfer is important in a wide spectrum of processes spanning biological, chemical and physical systems. These reactions have attracted significant interest due to both fundamental curiosity and potential applications in energy technology. In this Perspective Review, we shed light on modern aspects of electrode processes in the 21st century, in particular on the recent advances and challenges in multistep electron/proton transfers at solid-liquid interfaces.

Effect of hydrophobic cations on the oxygen reduction reaction on single‒crystal platinum electrodes.

Highly active catalysts for the oxygen reduction reaction are essential for the widespread and economically viable use of polymer electrolyte fuel cells. Here we report the oxygen reduction reaction activities of single‒crystal platinum electrodes in acidic solutions containing tetraalkylammonium cations with different alkyl chain lengths. The high hydrophobicity of a tetraalkylammonium cation with a longer alkyl chain enhances the oxygen reduction reaction activity.

Interfacial Structure of PtNi Surface Alloy on Pt(111) Electrode for Oxygen Reduction Reaction.

The interfacial structure and activity for the oxygen reduction reaction (ORR) were investigated on a PtNi surface alloy on a Pt(111) electrode (PtNi/Pt(111)). The PtNi surface alloy was prepared by thermal annealing of Ni modified on Pt(111) at 573-803 K. After optimizing the alloying temperature and the amount of added Ni, the ORR current density of PtNi/Pt(111) at 0.