2023 New's Items

Iodide oxidation by ozone at the surface of aqueous microdroplets

Prophet AM
Ghosh A
Limmer DT
2023

The oxidation of iodide by ozone occurs at the sea-surface and within sea spray aerosol, influencing the overall ozone budget in the marine boundary layer and leading to the emission of reactive halogen gases. A detailed account of the surface mechanism has proven elusive, however, due to the difficulty in quantifying multiphase kinetics. To obtain a clearer understanding of this reaction mechanism at the air–water interface, we report pH-dependent oxidation kinetics of I− in single levitated microdroplets as a function of [O3] using...

Selective Synthesis of Defect-Rich LaMnO3 by Low-Temperature Anion Cometathesis

Tran GT
Wustrow A
O’Nolan D
Tao S
Bartel CJ
He T
2023

The synthesis of complex oxides at low temperatures brings forward aspects of chemistry not typically considered. This study focuses on perovskite LaMnO3, which is of interest for its correlated electronic behavior tied to the oxidation state and thus the spin configuration of manganese. Traditional equilibrium synthesis of these materials typically requires synthesis reaction temperatures in excess of 1000 °C, followed by subsequent annealing steps at lower temperatures and different p(O2) conditions to manipulate the...

Congratulations to the 2023 Kavli ENSI Fellowship Recipients!

August 1, 2023

Energy Funneling in a Noninteger Two-Dimensional Perovskite

Oddo A
Yang P
2023

Energy funneling is a phenomenon that has been exploited in optoelectronic devices based on low-dimensional materials to improve their performance. Here, we introduce a new class of two-dimensional semiconductor, characterized by multiple regions of varying thickness in a single confined nanostructure with homogeneous composition. This “noninteger 2D semiconductor” was prepared via the structural transformation of two-octahedron-layer-thick (n = 2) 2D cesium lead bromide perovskite nanosheets; it consisted of a central n = 2 region surrounded by edge-lying...

Operando methods: A new era of electrochemistry

Yang Y
Yang P
2023

One of the grand challenges facing electrochemistry is to directly resolve the complex nature of (electro)catalyst active sites and capture real-time “movies” of reaction dynamics, i.e. “watching chemistry in action”. The need for such fundamental understanding has stimulated the development of operando/in situ methods, which have greatly enhanced our ability to identify activity descriptors of electrocatalysts and establish structure–property relationships of energy materials. This review summarizes the frontiers of operando electrochemical liquid-cell scanning transmission electron...

Operando High-Energy-Resolution X-ray Spectroscopy of Evolving Cu Nanoparticle Electrocatalysts for CO2 Reduction

Feijóo J
Yang P
2023

Advances in electrocatalysis research rely heavily on building a thorough mechanistic understanding of catalyst active sites under realistic operating conditions. Only recently have techniques emerged that enable sensitive spectroscopic data collection to distinguish catalytically relevant surface sites from the underlying bulk material under applied potential in the presence of an electrolyte layer. Here, we demonstrate that operando high-energy-resolution fluorescence detected X-ray absorption spectroscopy (HERFD-XAS) is a powerful spectroscopic method which offers...

High-Photovoltage Silicon Nanowire for Biological Cofactor Production

Lineberry E
Yang P
2023

Photocathodic conversion of NAD+ to NADH cofactor is a promising platform for activating redox biological catalysts and enzymatic synthesis using renewable solar energy. However, many photocathodes suffer from low photovoltage, consequently requiring a high cathodic bias for NADH production. Here, we report an n+p-type silicon nanowire (n+p-SiNW) photocathode having a photovoltage of 435 mV to drive energy-efficient NADH production. The enhanced band bending at the n+/p interface accounts for the high photovoltage, which conduces to a...

Synthesis of Carbohydrates from Methanol Using Electrochemical Partial Oxidation over Palladium with the Integrated Formose Reaction

Soland N
Yang P
2023

Electrochemically derived multicarbon products are a golden target for valorization of captured carbon dioxide due to the potential of turning a waste product into useful commodity chemicals with renewable energy sources. As a tantalizing approach toward their synthesis, the formose reaction utilizes catalytic condensation of formaldehyde to generate carbohydrates. While a sustainable approach to artificial carbohydrate production through electrochemical generation of formaldehyde is desirable, to date, it has not been fully realized. Here, we study the electrocatalytic conversion of...

High-entropy halide perovskite single crystals stabilized by mild chemistry

Folgueras MC
Yang P
2023

Although high-entropy materials are excellent candidates for a range of functional materials, their formation traditionally requires high-temperature synthetic procedures of over 1,000 °C and complex processing techniques such as hot rolling1,...

Understanding the Structural Evolution of IrFeCoNiCu High-Entropy Alloy Nanoparticles under the Acidic Oxygen Evolution Reaction

Maulana AL
Yang P
2023

High-entropy alloy (HEA) nanoparticles are promising catalyst candidates for the acidic oxygen evolution reaction (OER). Herein, we report the synthesis of IrFeCoNiCu-HEA nanoparticles on a carbon paper substrate via a microwave-assisted shock synthesis method. Under OER conditions in 0.1 M HClO4, the HEA nanoparticles exhibit excellent activity with an overpotential of ∼302 mV measured at 10 mA cm–2 and improved stability over 12 h of operation compared to the monometallic Ir counterpart. Importantly, an active Ir-rich shell layer...