Search

Reducing the precious metal content of water oxidation catalysts for proton-exchange-membrane water electrolyzers remains a critical barrier to their large-scale deployment. Herein, we present an engineered architecture for supported iridium catalysts, which enables decreased precious metal content and improved activity and conductivity. The improvement in performance at lower precious metal loading is realized by the deposition of a conformal layer of platinum nanoparticles on titanium dioxide (TiO2) using a facile photoreduction method to prepare conductive layer coated supports (CCSs). Platinum nanoparticles are homogeneously dispersed on TiO2, and the conductivity of the subsequent catalysts with 39 wt % precious group metal loadings is significantly higher than the commercial 75 wt % loaded IrO2-TiO2 catalysts. The conformal conductive layer also maintains an enhanced conductivity and electrochemical activity upon thermal annealing when compared to catalysts without the conductive layer and nonconformal heterogeneous conductive layer. The iridium mass activity from half-cell studies shows a 141% improvement for CCS supported catalysts at 42% lower loadings compared to the commercial catalysts. The conductive layer also improves the single cell electrolyzer performance at a similar catalyst loading in comparison to a commercial state-of-the-art catalyst. We correlate the physical properties of the engineered catalysts with their electrochemical performance in electrolyzers to understand structure-activity relationships, and we anticipate further performance improvements upon synthesis and materials optimizations.

A recent meeting focused on accelerated materials design and discovery examined user requirements for a general, collaborative, integrative, and on-demand materials research platform.

We demonstrate the translation of a low-cost, non-precious metal cobalt phosphide (CoP) catalyst from 1 cm2 lab-scale experiments to a commercial-scale 86 cm2 polymer electrolyte membrane (PEM) electrolyser. A two-step bulk synthesis was adopted to produce CoP on a high-surface-area carbon support that was readily integrated into an industrial PEM electrolyser fabrication process. The performance of the CoP was compared head to head with a platinum-based PEM under the same operating conditions (400 psi, 50 °C). CoP was found to be active and stable, operating at 1.86 A cm-2 for >1,700 h of continuous hydrogen production while providing substantial material cost savings relative to platinum. This work illustrates a potential pathway for non-precious hydrogen evolution catalysts developed in past decades to translate to commercial applications.

We report, to our knowledge for the first time, a combined experimental and density functional theory (DFT) investigation into the activity and stability of cobalt, molybdenum, and copper arsenides as catalysts for the hydrogen evolution reaction (HER). We find CoAs and MoAs to be the most active arsenide materials. We discuss the trends between calculated surface vacancy formation energies and catalyst stability. Using a simple thermodynamic model of HER activity, we find consistent trends between hydrogen binding free energy and the experimentally observed activity.

Multimetallic Ir-based systems offer significant opportunities for enhanced oxygen evolution electrocatalysis by modifying the electronic and geometric properties of the active catalyst. Herein, a systematic investigation of bimetallic Ir-based thin films was performed to identify activity and stability trends across material systems for the oxygen evolution reaction (OER) in acidic media. Electron beam evaporation was used to co-deposit metallic films of Ir, IrSn2, IrCr, IrTi, and IrNi. The electrocatalytic activity of the electrochemically oxidized alloys was found to increase in the following order: IrTi < IrSn2 < Ir ∼ IrNi < IrCr. The IrCr system demonstrates two times the catalytic activity of Ir at 1.65 V versus RHE. Density functional theory calculations suggest that this enhancement is due to Cr active sites that have improved oxygen binding energetics compared to those of pure Ir oxide. This work identifies IrCr as a promising new catalyst system that facilitates reduced precious metal loadings for acid-based OER catalysis.

Introduction Vestibular/Ocular Motor Screening (VOMS) is often part of a comprehensive evaluation to identify acute mild traumatic brain injury. Most of the reports describe the use of the VOMS in adolescents/young adults and not in older adults or military service members. The purpose of this study was to describe VOMS findings in healthy civilians and active duty military service members up to the age of 50 years. Materials and Methods Seventy-seven healthy civilians between 18 and 50 years of age (22 males, age 31.8 [9.0] years) participated across three sites in addition to 40 healthy active duty service members (25 males, age 27.5 [4.9] years) from one site. Demographics, Neurobehavioral Symptom Inventory scores, mean near point convergence (NPC) distance, and Total Symptom Change (TSS) scores from the VOMS were evaluated. Results For civilians, the group mean NPC distance was 4.98 (3.8) cm. For military service members, the group mean NPC distance was 6.17 (4.57) cm. For civilians, the mean TSS was 1.2 (2.3) with 53.2% reporting 0 TSS, 27.3% reporting one TSS, and 19.5% reporting two or more TSS. For military service members, the mean TSS was 0.20 (0.72) with 92.5% reporting 0 TSS, 0% reporting one TSS, and 7.5% reporting two or more TSS. Age did not correlate with the mean NPC distance and TSS in healthy civilians and active duty military service members. Conclusions Reconsideration of the Military Acute Concussion Evaluation, Version 2 cutoff value for abnormal mean NPC distance may be warranted to improve diagnostic accuracy in both civilian and military adult populations. Similarly, re-evaluating criteria for interpreting the TSS results of the VOMS, specifically in civilians, may be warranted. [ABSTRACT FROM AUTHOR]

After a mild traumatic brain injury (mTBI), dizziness and balance problems are frequently reported, affecting individuals' daily lives and functioning. Vestibular rehabilitation is a standard treatment approach for addressing these issues, but its efficacy in this population remains inconclusive. A potential reason for suboptimal outcomes is the lack of objective monitoring of exercise performance, which is crucial for therapeutic success. This study utilized wearable inertial measurement units (IMUs) to quantify exercise performance in individuals with mTBI during home-based vestibular rehabilitation exercises. Seventy-three people with mTBI and fifty healthy controls were enrolled. Vestibular exercises were performed, and IMUs measured forehead and sternum velocities and range of motions. The mTBI group demonstrated a slower forehead peak angular velocity in all exercises, which may be a compensatory strategy to manage balance issues or symptom exacerbation. Additionally, the mTBI group exhibited a larger forehead range of motion during specific exercises, potentially linked to proprioceptive deficits. These findings emphasize the usefulness of utilizing IMUs to monitor the quality of home-based vestibular exercises for individuals with mTBI and the potential for IMUs improving rehabilitation outcomes. [ABSTRACT FROM AUTHOR]