On-Chip in Situ Monitoring of Competitive Interfacial Anionic Chemisorption as a Descriptor for Oxygen Reduction Kinetics

Abstract

The development of future sustainable energy technologies relies critically on our understanding of electrocatalytic reactions occurring at the electrode–electrolyte interfaces, and the identification of key reaction promoters and inhibitors. Here we present a systematic in situ nanoelectronic measurement of anionic surface adsorptions (sulfates, halides, and cyanides) on ultrathin platinum nanowires during active electrochemical processes, probing their competitive adsorption behavior with oxygenated species and correlating them to the electrokinetics of the oxygen reduction reaction (ORR). The competitive anionic adsorption features obtained from our studies provide fundamental insight into the surface poisoning of Pt-catalyzed ORR kinetics by various anionic species. Particularly, the unique nanoelectronic approach enables highly sensitive characterization of anionic adsorption and opens an efficient pathway to address the practical poisoning issue (at trace level contaminations) from a fundamental perspective. Through the identified nanoelectronic indicators, we further demonstrate that rationally designed competitive anionic adsorption may provide improved poisoning resistance, leading to performance (activity and lifetime) enhancement of energy conversion devices.

Regulating the Inner Helmholtz Plane for Stable Solid Electrolyte Interphase on Lithium Metal Anodes

“…The geometrical structures and binding energies of these interactions are summarized in Figure and Figure S7. Generally, the Li slab affords a much larger binding energy toward anions (−4.44 to −6.35 eV) than Li + (−1.96 to −1.50 eV), which is consistent with previous reports that anions dominate in the IHP. − The large binding energies of anions are induced by the as-formed strong Li–O/N/F interactions as well as a significant charge transfer. The Li–O/Li–N bond lengths are 2.024/1.804 and 2.201/2.341 Å in the FSI – and NO 3 – models, respectively, similar to that in Li 2 O (2.017 Å) and Li 3 N (2.108 Å) crystals (Figure f).…”

Ag+ Interference from Ag/AgCl Wire Quasi-Reference Counter Electrode Inducing Corrosion Potential Shift in an Oil-Immersed Scanning Micropipette Contact Method Measurement

“…The double-junction Ag/AgCl RE was proposed to mitigate the Ag + leakage, , but it is not suitable for the micropipette due to the difficulty of miniaturization. A leak-free Ag/AgCl electrode, which uses a highly conductive but not porous junction to prevent the solution migration in either direction, would be one choice for OI-SMCM measurements. − The leak-free Ag/AgCl used here has a potential difference of 1.7 mV versus SCE in the 3.5 wt % NaCl solution (Figure S7), which is close to the potential of the Ag/AgCl wire. The setup shown in Figure b presents one configuration to connect the leak-free Ag/AgCl QRCE to a micropipette with a holder. , Other configurations could be developed on the basis of various types of commercial and homemade holders.…”

Pt‐Based Nanocrystal for Electrocatalytic Oxygen Reduction

“…Recently, The Huang and Duan groups leveraged their expertise in nanoscale electronics and device fabrication and developed an electron transport spectroscopic (ETS) technique, [113] including concurrent on-chip voltammetry and in situ nanoelectronic measurements, to provide a complementary strategy to traditional spectroscopy-based characterization techniques for in situ monitoring EEI of the realistic catalytic components during electrocatalytic reactions. [113][114][115] It is expected that a better understanding of the structure-function relation of the electrocatalysts and of the EEI can contribute significantly to the rational design of high-performing catalysts in nanoscale or even in atomic scale. At the device level, the obstacle that restrains the wide-spread applications of Pt-based electro-catalysts mainly lies on their cost, electrochemical stabilities, specific microstructures and interactions with various working components in an actual device.…”