Toward Hyphenated Infrared and Raman Spectroscopies in Interfacial Electrochemistry.

To address the pressing demand for hyphenated characterization of the electrode-electrolyte interfaces at the molecular level, we report herein a technical note to demonstrate the hyphenation of electrochemical surface-enhanced infrared absorption spectroscopy (SEIRAS) and shell-isolated nanoparticle enhanced Raman spectroscopy (SHINERS). The core setup incorporates a top-down configured Raman optic fiber head loaded on a 3-dimension positioning module and a bottom-up configured attenuated total reflection infrared spectroscopy (ATR-IR) spectroelectrochemical cell accommodated in a custom-designed optical accessory. The feasibility of this integrated design is initially validated by the simultaneous measurement of two model systems, namely, potential dependent adsorption of pyridine on a Au film electrode and the CO reduction reaction on a Cu film electrode by SEIRAS and SHINERS, yielding distinct and complementary spectral information.

Molecular level insights on the pulsed electrochemical CO reduction.

Electrochemical CO reduction reaction (CORR) occurring at the electrode/electrolyte interface is sensitive to both the potential and concentration polarization. Compared to static electrolysis at a fixed potential, pulsed electrolysis with alternating anodic and cathodic potentials is an intriguing approach that not only reconstructs the surface structure, but also regulates the local pH and mass transport from the electrolyte side in the immediate vicinity of the cathode. Herein, via a combined online mass spectrometry investigation with sub-second temporal resolution and 1-dimensional diffusion profile simulations, we reveal that heightened surface CO concentration promotes CORR over H evolution for both polycrystalline Ag and Cu electrodes after anodic pulses.

Disentangling heterogeneous thermocatalytic formic acid dehydrogenation from an electrochemical perspective.

Heterogeneous thermocatalysis of formic acid dehydrogenation by metals in solution is of great importance for chemical storage and production of hydrogen. Insightful understanding of the complicated formic acid dehydrogenation kinetics at the metal-solution interface is challenging and yet essential for the design of efficient heterogeneous formic acid dehydrogenation systems. In this work, formic acid dehydrogenation kinetics is initially studied from a perspective of electrochemistry by decoupling this reaction on Pd catalyst into two short-circuit half reactions, formic acid oxidation reaction and hydrogen evolution reaction and manipulating the electrical double layer impact from the solution side.

Electrifying HCOOH synthesis from CO building blocks over Cu-Bi nanorod arrays.

Precise electrochemical synthesis of commodity chemicals and fuels from CO building blocks provides a promising route to close the anthropogenic carbon cycle, in which renewable but intermittent electricity could be stored within the greenhouse gas molecules. Here, we report state-of-the-art CO-to-HCOOH valorization performance over a multiscale optimized Cu-Bi cathodic architecture, delivering a formate Faradaic efficiency exceeding 95% within an aqueous electrolyzer, a C-basis HCOOH purity above 99.8% within a solid-state electrolyzer operated at 100 mA cm for 200 h and an energy efficiency of 39.

Uncovering the Dissociative Adsorption of the Leveler Janus Green B on Cu Electrodes at the Molecular Level.

The interfacial adsorption structure of an organic leveler decides its functionality in Cu interconnect electroplating and is yet far from clear. In this work, attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and electrochemical quartz crystal microbalance (EQCM) in conjunction with density functional theory (DFT) calculations are applied to unravel the interfacial adsorption of the classic dye leveler Janus Green B (JGB) at a Cu electrode and understand its polarization property against Cu electrodeposition from an adsorption structure perspective. ATR-SEIRAS measurements and DFT calculations reveal that the N=N bond of the JGB molecule splits via reductive hydrogenation, forming two fragments of contrasting adsorption configurations.

Atomic Layer Deposition of TiO on Si Window Enables ATR-SEIRAS Measurements in Strong Alkaline Electrolytes.

The Si window is the most widely used internal reflection element (IRE) for electrochemical attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), yet local chemical etching on Si by concentrated OH anions bottlenecks the reliable application of this method in strong alkaline electrolytes. In this report, atomic layer deposition of a 25 nm nonconductive TiO barrier layer on the reflecting plane of a Si prism is demonstrated to address this challenge. ATR-SEIRAS measurement on a Au film electrode with the Si/TiO composite IRE in 1 M NaOH reveals reversible global spectral features without spectral distortion at 1000-1300 cm, in stark contrast to those obtained with a bare Si window.

Lutetium-Induced Ultrafine PtRu Nanoclusters with a High Electrochemical Surface Area for Direct Methanol Fuel Cells at Alleviated Temperatures.

PtRu alloys have been recognized as the state-of-the-art catalysts for the methanol oxidation reaction (MOR) in direct methanol fuel cells (DMFCs). However, their applications in DMFCs are still less efficient in terms of both catalytic activity and durability. Rare earth (RE) metals have been recognized as attractive elements to tune the catalytic activity, while it is still a world-class challenge to synthesize well-dispersed Pt-RE alloys.

Uncovering Photoelectronic and Photothermal Effects in Plasmon-Mediated Electrocatalytic CO Reduction.

Plasmon-mediated electrocatalysis that rests on the ability of coupling localized surface plasmon resonance (LSPR) and electrochemical activation, emerges as an intriguing and booming area. However, its development seriously suffers from the entanglement between the photoelectronic and photothermal effects induced by the decay of plasmons, especially under the influence of applied potential. Herein, using LSPR-mediated CO reduction on Ag electrocatalyst as a model system, we quantitatively uncover the dominant photoelectronic effect on CO reduction reaction over a wide potential window, in contrast to the leading photothermal effect on H evolution reaction at relatively negative potentials.

Improving the Efficiencies of Water Splitting and CO Electrolysis by Anodic O Bubble Management.

This study systematically explores the impact of the anodic flow field design on the transport of O bubble and subsequent energy efficiency in electrolysis devices. Two distinct configurations, namely a conventional serpentine flow panel and an interdigitated flow panel, are integrated at the anode side of the electrolyzer. The interdigitated flow field exhibits superior performance in both alkaline water splitting and CO reduction despite the experience of an increased pressure drop.

Plasmon-Enhanced C-C Bond Cleavage toward Efficient Ethanol Electrooxidation.

Ethanol, as a sustainable biomass fuel, is endowed with the merits of theoretically high energy density and environmental friendliness yet suffers from sluggish kinetics and low selectivity toward the desired complete electrooxidation (C1 pathway). Here, the localized surface plasmon resonance (LSPR) effect is explored as a manipulating knob to boost electrocatalytic ethanol oxidation reaction in alkaline media under ambient conditions by appropriate visible light. Under illumination, Au@Pt nanoparticles with plasmonic core and active shell exhibit concurrently higher activity (from 2.

In Situ Wide-Frequency Surface-Enhanced Infrared Absorption Spectroscopy Enables One to Decipher the Interfacial Structure of a Cu Plating Additive.

In situ spectroscopic characterization of the interfacial structure of an organic additive at a Cu electrode is essential for a mechanistic understanding of Cu superfilling at the molecular level. In this work, we demonstrate wide-frequency attenuated total reflection surface-enhanced infrared absorption spectroscopy (wf-ATR-SEIRAS) to elucidate the dissociative adsorption of bis(sodium sulfopropyl)-disulfide (a typical accelerator) on a Cu electrode in conjunction with the electrochemical quartz crystal microbalance measurement and modeling calculations. The wf-ATR-SEIRAS clearly identifies the peaks featuring the sulfonate and methylene groups as well as the C-S and C-S vibrations of the adsorbate.

Electrolyte-Layer-Tunable ATR-SEIRAS for Simultaneous Detection of Adsorbed and Dissolved Species in Electrochemistry.

A balanced detection of both adsorbates and dissolved species is very important for the clarification of the electrochemical reaction mechanism yet remains a major challenge for different modes of electrochemical infrared (IR) spectroscopy. Among others, conventional attenuated total reflection-surface-enhanced IR absorption spectroscopy (ATR-SEIRAS) is far less sensitive to low-concentration solution species than to surface species. We report herein an electrochemical wide-frequency ATR-SEIRAS with a novel thin-layer flow cell design, fulfilling the simultaneous detection of the variations of surface and solution species.

Preliminary study of carotid variables under ultrasound analysis as predictors for the risk of coronary arterial atherosclerosis.

Background: Carotid atherosclerosis by ultrasound scanning can be considered as an ideal window to reflect systemic artery atherosclerosis, which has aroused wide concern for predicting the severity of coronary artery atherosclerosis clinically. Ultrasound radio frequency (RF) data technology has enabled us to evaluate the carotid structure and elastic function precisely, for predicting the severity of coronary artery atherosclerosis.

Methods: Patients with suspected coronary artery disease (CAD) underwent coronary angiography and were assigned to four groups according to whether atherosclerotic plaque was found or not and it caused stenosis.

The severity of portal hypertension by a non-invasive assessment: acoustic structure quantification analysis of liver parenchyma.

Background: Acoustic structure quantification (ASQ) has been applied to evaluate liver histologic changes by analyzing the speckle pattern seen on B-mode ultrasound. We aimed to assess the severity of portal hypertension (PHT) through hepatic ultrasonography.

Methods: Sixty patients diagnosed with PHT and underwent surgical treatment with portosystemic shunts were enrolled.

Steering the Glycerol Electro-Reforming Selectivity via Cation-Intermediate Interactions.

Electro-reforming of renewable biomass resources is an alternative technology for sustainable pure H production. Herein, we discovered an unconventional cation effect on the concurrent formate and H production via glycerol electro-reforming. In stark contrast to the cation effect via forming double layers in cathodic reactions, residual cations at the anode were discovered to interact with the glycerol oxidation intermediates to steer its product selectivity.

Redox environment metabolomic evaluation (REME) of the heart after myocardial ischemia/reperfusion injury.

Myocardial ischemia/reperfusion injury (MIRI) is closely related to oxidative stress. However, the redox environment of the heart has not been evaluated thoroughly after MIRI, which limits precise redox intervention. In this study, we developed the redox environment metabolomic evaluation (REME) method to analyze the redox metabolites of the heart after MIRI.

Revisiting the Acetaldehyde Oxidation Reaction on a Pt Electrode by High-Sensitivity and Wide-Frequency Infrared Spectroscopy.

High-sensitivity and wide-frequency attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) is highly demanded in unraveling electrocatalytic processes at the molecular level. In this work, an in situ ATR-SEIRAS technique incorporating a micromachined Si wafer window, -polarized infrared radiation, and isotope labeling is extended to revisit the acetaldehyde oxidation reaction (AOR) on a Pt electrode in an acidic medium. New spectral features in the fingerprint region are detected, including ω(C-H) at 1078 cm and ν(C-C-O) at 919 cm for adsorbed acetaldehyde and δ(O-C-O) at 689 cm for adsorbed acetate, besides the other enhanced and clearly discriminated spectral signals at higher frequencies.

Interfacial Structure of Water as a New Descriptor of the Hydrogen Evolution Reaction.

Driven by the persisting poor understanding of the sluggish kinetics of the hydrogen evolution reaction (HER) on Pt in alkaline media, a direct correlation of the interfacial water structure and activity is still yet to be established. Herein, using Pt and Pt-Ni nanoparticles we first demonstrate a strong dependence of the proton donor structure on the HER activity and pH. The structure of the first layer changes from the proton acceptors to the donors with increasing pH.

Lipidomics reveals the dynamics of lipid profile altered by omega-3 polyunsaturated fatty acid supplementation in healthy people.

Glycerophospholipids (GPs) and sphingolipids (SPs) are important lipid components in the body and play biological functions. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) are important nutrients, and their supplements are commonly used for preventing some diseases. However, the effect of n-3 PUFAs on the human glycerophospholipidome and sphingolipidome is unclear.

Nature of Oxygen-Containing Groups on Carbon for High-Efficiency Electrocatalytic CO Reduction Reaction.

Oxygen-containing groups on carbon materials can induce high catalytic activity for some reactions. Herein, on the basis of a series of metal-free single-layer graphene nanodisks (GNDs) with different surface contents of oxygen-containing groups for highly efficient electrocatalytic reduction reaction of CO (CO2RR) to produce formate (HCOO), we find that the CO2RR catalytic performance is only positively correlated with the surface content of carboxyl groups. While significantly, the density functional theory calculations demonstrate that the observed high CO2RR catalytic activity originates not from the solo carboxyl or other oxygen-containing groups, but from the synergistic effect between carboxyl groups and adjacent other types of groups (namely, hydroxyl, epoxide, and carbonyl) on GNDs.