Negative Reaction Order for CO during CO Electroreduction on Au.

The potential-dependent negative fractional reaction orders with respect to the CO partial pressures were measured for CO electroreduction (COR) on Au under mass-transfer-controlled conditions using a rotating ring-disk electrode setup. At high overpotentials, the CO reaction order approaches -1 due to enhanced CO adsorption on Au, which is supported by kinetic analysis and density functional theory (DFT) simulations. This work illustrates that the CO site-blocking effect cannot be ignored, even on a weak CO-binding metal such as Au in the electrochemical environment.

Inverse CO /C H Separation with MFU-4 and Selectivity Reversal via Postsynthetic Ligand Exchange.

Although many porous materials, including metal-organic frameworks (MOFs), have been reported to selectively adsorb C H in C H /CO separation processes, CO -selective sorbents are much less common. Here, we report the remarkable performance of MFU-4 (Zn Cl (bbta) , bbta=benzo-1,2,4,5-bistriazolate) toward inverse CO /C H separation. The MOF facilitates kinetic separation of CO from C H , enabling the generation of high purity C H (>98 %) with good productivity in dynamic breakthrough experiments.

Strong CO Chemisorption in a Metal-Organic Framework with Proximate Zn-OH Groups.

A novel Zn benzotriazolate metal-organic framework (MOF), [Zn(OAc)(bbtm)] (, bbtm = bis(benzotriazolyl)methanone, OAc = acetate), has been synthesized and structurally characterized using micro-crystal electron diffraction. The framework contains 12-connected nonanuclear Zn clusters with Zn-OAc groups separated by short intercluster Zn···Zn distances of 6.06 Å.

Unraveling the electrocatalytic reduction mechanism of enols on copper in aqueous media.

Deoxygenation of aldehydes and their tautomers to alkenes and alkanes has implications in refining biomass-derived fuels for use as transportation fuel. Electrochemical deoxygenation in ambient, aqueous solution is also a potential green synthesis strategy for terminal olefins. In this manuscript, direct electrochemical conversion of vinyl alcohol and acetaldehyde on polycrystalline Cu to ethanol, ethylene and ethane; and propenol and propionaldehyde to propanol, propene and propane is reported.

Insights into Dynamic Surface Bromide Sites in Bi O Br for Sustainable N Photofixation.

Simulating photosynthesis has long been one of the ideas for realizing the conversion of solar energy into industrial chemicals. Heterogeneous N photofixation in water is a promising way for sustainable production of ammonia. However, a mechanistic understanding of the complex aqueous photocatalytic N reduction is still lacking.

Direct Evidence of Local pH Change and the Role of Alkali Cation during CO Electroreduction in Aqueous Media.

We report, for the first time, utilizing a rotating ring-disc electrode (RRDE) assembly for detecting changes in the local pH during aqueous CO reduction reaction (CO RR). Using Au as a model catalyst where CO is the only product, we show that the CO oxidation peak shifts by -86±2 mV/pH during CO RR, which can be used to directly quantify the change in the local pH near the catalyst surface during electrolysis. We then applied this methodology to investigate the role of cations in affecting the local pH during CO RR and find that during CO RR to CO on Au in an MHCO buffer (where M is an alkali metal), the experimentally measured local basicity decreased in the order Li > Na > K > Cs , which agreed with an earlier theoretical prediction by Singh et al.

Power Generation for Wearable Electronics: Designing Electrochemical Storage on Fabrics.

We report a new class of textiles with electrochemical functions which, when moistened by a conductive liquid (saline solution, sweat, wound fluid, etc.), generate DC voltage and current levels capable of powering wearable electronics on the go. Contrary to previously reported power generation techniques, the proposed fabrics are fully flexible, feel and behave like regular clothing, do not include any rigid components, and provide DC power via moistening by readily available liquids.

Characterization and performance of anodic mixed culture biofilms in submersed microbial fuel cells.

Microbial fuel cells (MFCs) were designed for laboratory scale experiments to study electroactive biofilms in anodic chambers. Anodic biofilms and current generation during biofilm growth were examined using single chambered MFCs submersed in algal catholyte. A culture of the marine green alga Nanochloropsis salina was used as a biocatholyte, and a rumen fluid microbiota was the anodic chamber inoculum.

Revealing Chemical Processes Involved in Electrochemical (De)Lithiation of Al with in Situ Neutron Depth Profiling and X-ray Diffraction.

Herein we report a direct measurement of Li transport in real-time during charge and discharge process within an Al matrix using neutron depth profiling (NDP). In situ NDP was used to reveal and quantify parasitic losses during the first 25 mAhr/g of lithiation, followed by the formation of LiAl protrusions from the surface of pristine Al. Evidence of Li entrapment is also reported during delithiation.

In situ quantification and visualization of lithium transport with neutrons.

A real-time quantification of Li transport using a nondestructive neutron method to measure the Li distribution upon charge and discharge in a Li-ion cell is reported. By using in situ neutron depth profiling (NDP), we probed the onset of lithiation in a high-capacity Sn anode and visualized the enrichment of Li atoms on the surface followed by their propagation into the bulk. The delithiation process shows the removal of Li near the surface, which leads to a decreased coulombic efficiency, likely because of trapped Li within the intermetallic material.

Mechanistic analysis of the oxygen reduction reaction at (La,Sr)MnO3 cathodes in solid oxide fuel cells.

The primary aim of this work was to establish the mechanism of the oxygen reduction reaction (ORR) at (La(0.8)Sr(0.2))0.

Impact of porous electrode properties on the electrochemical transfer coefficient.

The rate of an activation-controlled electrochemical reaction is determined by two key parameters, the exchange current density, io, and the transfer coefficient, alpha, which is inversely related to the Tafel slope. Assuming that the symmetry factor, beta, is 0.5, the minimum alpha value should be 0.