Identification of Active Regions in a Catalyst Layer on a Gas Diffusion Electrode in the Electroreduction of CO.

Although a gas diffusion electrode (GDE) has been widely employed in the electrochemical CO reduction reaction (CORR) to effectively mitigate mass transport limitations, knowledge of the active region within the catalyst layer on the GDE remains incomplete. In this work, we employed a thin layer of Bi as a reporter to identify the active region within the Ag catalyst layer by taking advantage of the distinct selectivity of these two metals in the CORR. Through manipulating the position of the Bi layer within the Ag layer, we showed that at 100 mA cm, the active region was located between 150 and 600 nm from the PTFE substrate.

Probing Inside the Catalyst Layer on Gas Diffusion Electrodes in Electrochemical Reduction of CO and CO.

Gas diffusion electrodes (GDEs) are widely used in electrochemical CO and CO reduction reactions (CORR) in flow cells due to their ability to alleviate mass transport limitations of gaseous reactants. The flow cell configuration makes uniform distribution of reactants, intermediates, products, and speciation within the catalyst layer (CL) unlikely. In this work, a first-of-its-kind in situ characterization technique capable of probing the cross section of the CL with confocal Raman spectroscopy was developed to investigate the speciation distribution across the Cu CL in CORR with a spatial resolution of ∼4 µm.

Bridging activity gaps between batch and flow reactor configurations in the electroreduction of carbon dioxide.

To date, the understanding of various modes of CO mass transport remains incomplete, impeding the transfer of catalysts identified in the more accessible electrochemical batch cells to high-performance flow cells. In this work, we demonstrate that the meniscus region formed between the electrode and the convex liquid level due to the electrowetting of the catalyst plays a vital role in the CORR in batch cells. CORR in the meniscus region in batch cells exhibits similar performance with that in flow cells, and the performance disparity between these two configurations largely disappears when conducting CORR primarily in the meniscus region.

Spin-Polarized PdCu-FeO In-Plane Heterostructures with Tandem Catalytic Mechanism for Oxygen Reduction Catalysis.

Alloying has significantly upgraded the oxygen reduction reaction (ORR) of Pd-based catalysts through regulating the thermodynamics of oxygenated intermediates. However, the unsatisfactory activation ability of Pd-based alloys toward O molecules limits further improvement of ORR kinetics. Herein, the precise synthesis of nanosheet assemblies of spin-polarized PdCu-FeO in-plane heterostructures for drastically activating O molecules and boosting ORR kinetics is reported.

Bifunctional Near-Neutral Electrolyte Enhances Oxygen Evolution Reaction.

Performance of electrocatalytic reactions depends on not only the composition and structure of the active sites, but also their local environment, including the surrounding electrolyte. In this work, we demonstrate that BF (OH) anion is the key fluoroborate species formed in the mixed KBi/KF (KBi=potassium borate) electrolyte to enhance the rate of the oxygen evolution reaction (OER) at near-neutral pH. Through a combination of electrokinetic and in situ spectroscopic studies, we show that the mixed KBi/KF electrolyte promotes the OER via two pathways: 1) stabilizing the interfacial pH during the proton-producing reaction with its high buffering capacity; and 2) activating the interfacial water via strong hydrogen bonds with F-containing species.

Macrophage-Targeted Dextran Sulfate-Dexamethasone Conjugate Micelles for Effective Treatment of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic, systemic immune disease that causes joint affection and even disability. Activated macrophages play an important role in the pathogenesis and progression of RA by producing pro-inflammatory factors. The use of dexamethasone (DXM) is effective in relieving the intractable pain and inflammatory progression of RA.

Catalytic Amination of Polylactic Acid to Alanine.

In comparison to the traditional petroleum-based plastics, polylactic acid, the most popular biodegradable plastic, can be decomposed into carbon dioxide and water in the environment. However, the natural degradation of polylactic acid requires a substantial period of time and, more importantly, it is a carbon-emitting process. Therefore, it is highly desirable to develop a novel transformation process that can upcycle the plastic trash into value-added products, especially with high chemical selectivity.