Cooperative Effect of Cations and Catalyst Structure in Tuning Alkaline Hydrogen Evolution on Pt Electrodes.

The kinetics of hydrogen evolution reaction (HER) in alkaline media, a reaction central to alkaline water electrolyzers, is not accurately captured by traditional adsorption-based activity descriptors. As a result, the exact mechanism and the main driving force for the water reduction or HER rate remain hotly debated. Here, we perform extensive kinetic measurements on the pH- and cation-dependent HER rate on Pt single-crystal electrodes in alkaline conditions.

Operando studies reveal active Cu nanograins for CO electroreduction.

Carbon dioxide electroreduction facilitates the sustainable synthesis of fuels and chemicals. Although Cu enables CO-to-multicarbon product (C) conversion, the nature of the active sites under operating conditions remains elusive. Importantly, identifying active sites of high-performance Cu nanocatalysts necessitates nanoscale, time-resolved operando techniques.

Resonant Soft X-ray Scattering Studies of Chemical Environment and Interparticle Dynamics of Cu Nanocatalysts for CO Electroreduction.

Understanding the chemical environment and interparticle dynamics of nanoparticle electrocatalysts under operating conditions offers valuable insights into tuning their activity and selectivity. This is particularly important to the design of Cu nanocatalysts for CO electroreduction due to their dynamic nature under bias. Here, we have developed electrochemical resonant soft X-ray scattering (EC-RSoXS) to probe the chemical identity of active sites during the dynamic structural transformation of Cu nanoparticle (NP) ensembles through 1 μm thick electrolyte.

The presence and role of the intermediary CO reservoir in heterogeneous electroreduction of CO.

SignificanceThe electroconversion of CO to value-added products is a promising path to sustainable fuels and chemicals. However, the microenvironment that is created during CO electroreduction near the surface of heterogeneous Cu electrocatalysts remains unknown. Its understanding can lead to the development of ways to improve activity and selectivity toward multicarbon products.

Photoelectrochemical CO Reduction toward Multicarbon Products with Silicon Nanowire Photocathodes Interfaced with Copper Nanoparticles.

The development of photoelectrochemical systems for converting CO into chemical feedstocks offers an attractive strategy for clean energy storage by directly utilizing solar energy, but selectivity and stability for these systems have thus been limited. Here, we interface silicon nanowire (SiNW) photocathodes with a copper nanoparticle (CuNP) ensemble to drive efficient photoelectrochemical CO conversion to multicarbon products. This integrated system enables CO-to-CH conversion with faradaic efficiency approaching 25% and partial current densities above 2.

The Interactive Dynamics of Nanocatalyst Structure and Microenvironment during Electrochemical CO Conversion.

In the pursuit of a decarbonized society, electrocatalytic CO conversion has drawn tremendous research interest in recent years as a promising route to recycling CO into more valuable chemicals. To achieve high catalytic activity and selectivity, nanocatalysts of diverse structures and compositions have been designed. However, the dynamic structural transformation of the nanocatalysts taking place under operating conditions makes it difficult to study active site configurations present during the CO reduction reaction (CORR).

Nanoparticle Assembly Induced Ligand Interactions for Enhanced Electrocatalytic CO Conversion.

The microenvironment in which the catalysts are situated is as important as the active sites in determining the overall catalytic performance. Recently, it has been found that nanoparticle (NP) surface ligands can actively participate in creating a favorable catalytic microenvironment, as part of the nanoparticle/ordered-ligand interlayer (NOLI), for selective CO conversion. However, much of the ligand-ligand interactions presumed essential to the formation of such a catalytic interlayer remains to be understood.

Ligand-Free Processable Perovskite Semiconductor Ink.

Traditional covalent semiconductors require complex processing methods for device fabrication due to their high cohesive energies. Here, we develop a stable, ligand-free perovskite semiconductor ink that can be used to make patterned semiconductor-based optoelectronics in one step. The perovskite ink is formed via the dissolution of crystals of vacancy-ordered double perovskite CsTeX (X = Cl, Br, I) in polar aprotic solvents, leading to the stabilization of isolated [TeX] octahedral anions and free Cs cations without the presence of ligands.

Ligand removal of Au nanoclusters by thermal and electrochemical treatments for selective CO electroreduction to CO.

Undercoordinated metal nanoclusters have shown great promise for various catalytic applications. However, their activity is often limited by the covalently bonded ligands, which could block the active surface sites. Here, we investigate the ligand removal process for Au nanoclusters using both thermal and electrochemical treatments, as well as its impact on the electroreduction of CO to CO.

A New Perspective and Design Principle for Halide Perovskites: Ionic Octahedron Network (ION).

The metal halide ionic octahedron, [MX] (M = metal cation, X = halide anion), is considered to be the fundamental building block and functional unit of metal halide perovskites. By representing the metal halide ionic octahedron in halide perovskites as a super ion/atom, the halide perovskite can be described as an extended ionic octahedron network (ION) charge balanced by selected cations. This new perspective of halide perovskites based on ION enables the prediction of different packing and connectivity of the metal halide octahedra based on different solid-state lattices.

Scaling Laws of Exciton Recombination Kinetics in Low Dimensional Halide Perovskite Nanostructures.

Carrier recombination is a crucial process governing the optical properties of a semiconductor. Although various theoretical approaches have been utilized to describe carrier behaviors, a quantitative understanding of the impact of defects and interfaces in low dimensional semiconductor systems is still elusive. Here, we develop a model system consisting of chemically tunable, highly luminescent halide perovskite nanocrystals to illustrate the role of carrier diffusion and material dimensionality on the carrier recombination kinetics and luminescence efficiency.

Electrochemically scrambled nanocrystals are catalytically active for CO-to-multicarbons.

Promotion of C-C bonds is one of the key fundamental questions in the field of CO electroreduction. Much progress has occurred in developing bulk-derived Cu-based electrodes for CO-to-multicarbons (CO-to-C), especially in the widely studied class of high-surface-area "oxide-derived" copper. However, fundamental understanding into the structural characteristics responsible for efficient C-C formation is restricted by the intrinsic activity of these catalysts often being comparable to polycrystalline copper foil.

Mitochondria Alkylation and Cellular Trafficking Mapped with a Lipophilic BODIPY-Acrolein Fluorogenic Probe.

Protein and DNA alkylation by endogenously produced electrophiles is associated with the pathogenesis of neurodegenerative diseases, to epigenetic alterations and to cell signaling and redox regulation. With the goal of visualizing, in real-time, the spatiotemporal response of the cell milieu to electrophiles, we have designed a fluorogenic BODIPY-acrolein probe, AcroB, that undergoes a >350-fold fluorescence intensity enhancement concomitant with protein adduct formation. AcroB enables a direct quantification of single post-translational modifications occurring on cellular proteins via recording fluorescence bursts in live-cell imaging studies.