Improved Rate for the Oxygen Reduction Reaction in a Sulfuric Acid Electrolyte using a Pt(111) Surface Modified with Melamine.

The feasible commercialization of alkaline, phosphoric acid and polymer electrolyte membrane fuel cells depends on the development of oxygen reduction reaction (ORR) electrocatalysts with improved activity, stability, and selectivity. The rational design of surfaces to ensure these improved ORR catalytic requirements relies on the so-called "descriptors" (e.g.

Anion Association Strength as a Unifying Descriptor for the Reversibility of Divalent Metal Deposition in Nonaqueous Electrolytes.

Developing next-generation battery chemistries that move beyond traditional Li-ion systems is critical to enabling transformative advances in electrified transportation and grid-level energy storage. In this work, we provide the first evidence for common descriptors for improved reversibility of metal plating/stripping in nonaqueous electrolytes for multivalent ion batteries. Focusing first on the specific role of chloride (Cl) in promoting electrochemical reversibility in multivalent systems, rotating disk (RDE) and ring-disk electrode (RRDE) investigations were performed utilizing a variety of divalent cations (Mg, Zn, and Cu) and the bis-(trifluoromethane sulfonyl) imide (TFSI) anion.

The role of an interface in stabilizing reaction intermediates for hydrogen evolution in aprotic electrolytes.

By combining idealized experiments with realistic quantum mechanical simulations of an interface, we investigate electro-reduction reactions of HF, water and methanesulfonic acid (MSA) on the single crystal (111) facets of Au, Pt, Ir and Cu in organic aprotic electrolytes, 1 M LiPF in EC/EMC 3:7W (LP57), the aprotic electrolyte commonly used in Li-ion batteries, 1 M LiClO in EC/EMC 3:7W and 0.2 M TBAPF in 3 : 7 EC/EMC. In our previous work, we have established that LiF formation, accompanied by H evolution, is caused by a reduction of HF impurities and requires the presence of Li at the interface, which catalyzes the HF dissociation.

Real-Time Monitoring of Cation Dissolution/Deintercalation Kinetics from Transition-Metal Oxides in Organic Environments.

The future of high-voltage rechargeable batteries is closely tied to the fundamental understanding of the processes that lead to the potential-dependent degradation of electrode materials and organic electrolytes. To date, however, there have been no methods able to provide quantitative, in situ and in real time information about the electrode dissolution kinetics and concomitant electrolyte decomposition during charge/discharge. We describe the development of such a method, which is of both fundamental and technological significance.

Electrochemical Dissolution of Iridium and Iridium Oxide Particles in Acidic Media: Transmission Electron Microscopy, Electrochemical Flow Cell Coupled to Inductively Coupled Plasma Mass Spectrometry, and X-ray Absorption Spectroscopy Study.

Iridium-based particles, regarded as the most promising proton exchange membrane electrolyzer electrocatalysts, were investigated by transmission electron microscopy and by coupling of an electrochemical flow cell (EFC) with online inductively coupled plasma mass spectrometry. Additionally, studies using a thin-film rotating disc electrode, identical location transmission and scanning electron microscopy, as well as X-ray absorption spectroscopy have been performed. Extremely sensitive online time-and potential-resolved electrochemical dissolution profiles revealed that Ir particles dissolve well below oxygen evolution reaction (OER) potentials, presumably induced by Ir surface oxidation and reduction processes, also referred to as transient dissolution.

Stability of commercial Pt/C low temperature fuel cell catalyst: electrochemical IL-SEM study.

Platinum catalyst stability has been investigated under potentiostatic and potentiodynamic conditions with and without the presence of chloride anions. The combination of rotating disc electrode (RDE) and identical location scanning electron microscopy (IL-SEM) methods reveals that potentiodynamic degradation is much more severe compared to the potentiostatic and that chloride enhances platinum dissolution thus catalyst degradation. IL-SEM method nicely shows the platinum dissolution and redeposition on the top of a catalyst film.

Growth of arrays of oriented epitaxial platinum nanoparticles with controlled size and shape by natural colloidal lithography.

We developed a method for production of arrays of platinum nanocrystals of controlled size and shape using templates from ordered silica bead monolayers. Silica beads with nominal sizes of 150 and 450 nm were self-assembled into monolayers over strontium titanate single crystal substrates. The monolayers were used as shadow masks for platinum metal deposition on the substrate using the three-step evaporation technique.

SEM method for direct visual tracking of nanoscale morphological changes of platinum based electrocatalysts on fixed locations upon electrochemical or thermal treatments.

A general method for tracking morphological surface changes on a nanometer scale with scanning electron microscopy (SEM) is introduced. We exemplify the usefulness of the method by showing consecutive SEM images of an identical location before and after the electrochemical and thermal treatments of platinum-based nanoparticles deposited on a high surface area carbon. Observations reveal an insight into platinum based catalyst degradation occurring during potential cycling treatment.

Zinc-decorated silica-coated magnetic nanoparticles for protein binding and controlled release.

The aim of this study was to be able to reversibly bind histidine-rich proteins to the surface of maghemite magnetic nanoparticles via coordinative bonding using Zn ions as the anchoring points. We showed that in order to adsorb Zn ions on the maghemite, the surface of the latter needs to be modified. As silica is known to strongly adsorb zinc ions, we chose to modify the maghemite nanoparticles with a nanometre-thick silica layer.