Steric stabilization of colloidal UiO-66 nanocrystals with oleylammonium octadecylphosphonate.

We report the synthesis and characterization of octahedral UiO-66 nanocrystals ( = 17-25 nm) terminated with amine, oleate, and octadecylphosphonate ligands. Acetate capped UiO-66 nanocrystals were dispersed in toluene using oleic acid and oleylamine. Ligand exchange with octadecylphosphonic acid produces ammonium octadecylphosphonate terminated nanocrystals with coverages of 2.

Toward Spatial Control of Reaction Selectivity on Photocatalysts Using Area-Selective Atomic Layer Deposition on the Model Dual Site Electrocatalyst Platform.

Photocatalytic water splitting is a promising route to low-cost, green H. However, this approach is currently limited in its solar-to-hydrogen conversion efficiency. One major source of efficiency loss is attributed to the high rates of undesired side and back reactions, which are exacerbated by the proximity of neighboring oxidation and reduction sites.

Assessment of Ammoniacal Leaching Agents for Metal Cation Extraction from Construction Wastes in Mineral Carbonation.

The use of carbon mineralization to produce carbonates from alkaline industrial wastes is gaining traction as a method to decarbonize the built environment. One of the environmental concerns during this process is the use of acids, which are required to extract Ca or Mg from the alkaline waste to produce carbonates. Conventionally, acids such as hydrochloric, nitric, or sulfuric are used which allow for the highest material recovery but are corrosive and difficult to regenerate as they are utilized in a linear fashion and generate additional process waste.

Oxide-Encapsulated Silver Electrocatalysts for Selective and Stable Syngas Production from Reactive Carbon Capture Solutions.

Electrolysis of bicarbonate-containing CO capture solutions is a promising approach towards achieving low-cost carbon-neutral chemicals production. However, the parasitic bicarbonate-mediated hydrogen evolution reaction (HER) and electrode instability in the presence of trace impurities remain major obstacles to overcome. This work demonstrates that the combined use of titanium dioxide (TiO) overlayers with the chelating agent ethylene diamine tetra-acetic acid (EDTA) significantly enhances the selectivity and stability of Ag-based electrocatalysts for bicarbonate electrolysis.

Carbon capture in polymer-based electrolytes.

Nanoparticle organic hybrid materials (NOHMs) have been proposed as excellent electrolytes for combined CO capture and electrochemical conversion due to their conductive nature and chemical tunability. However, CO capture behavior and transport properties of these electrolytes after CO capture have not yet been studied. Here, we use a variety of nuclear magnetic resonance (NMR) techniques to explore the carbon speciation and transport properties of branched polyethylenimine (PEI) and PEI-grafted silica nanoparticles (denoted as NOHM-I-PEI) after CO capture.

Elucidating the assembly of nanoparticle organic hybrid materials (NOHMs) near an electrode interface with varying potential using neutron reflectivity.

A critical concern regarding electrolyte formulation in an electrochemical environment is the impact of the interaction of the multiple components (, supporting electrolyte or additive) with the electrode surface. Recently, liquid-like neat Nanoparticle Organic Hybrid Materials (NOHMs) have been considered as an electrolyte component to improve the transport of redox-active species to the electrode surface. However, the structure and assembly of the NOHMs near the electrode surface is unknown and could significantly impact the electrode-electrolyte interface.

Confronting the Carbon-Footprint Challenge of Blockchain.

The distributed consensus mechanism is the backbone of the rapidly developing blockchain network. Blockchain platforms consume vast amounts of electricity based on the current consensus mechanism of Proof-of-Work (PoW). Here, we point out a different consensus mechanism named Proof-of-Stake (PoS) that can eliminate the extensive energy consumption of the current PoW-based blockchain.

Introduction to CO capture and conversion.

An introduction to the themed collection on CO capture and conversion, featuring exciting research on advanced nanoscale materials and reactions.

Probing the Effects of Electrode Composition and Morphology on the Effectiveness of Silicon Oxide Overlayers to Enhance Selective Oxygen Evolution in the Presence of Chloride Ions.

Seawater electrolysis offers significant logistical advantages over freshwater electrolysis but suffers from a fundamental selectivity problem at the anode. To prevent the evolution of toxic chlorine alongside the evolution of oxygen, a promising approach is the use of electrochemically inert overlayers. Such thin films can exert a perm-selective effect, allowing the transport of water and oxygen between the bulk electrolyte and the electrocatalytic buried interface while suppressing the transport of chloride ions.

Quantifying the Influence of Defects on Selectivity of Electrodes Encapsulated by Nanoscopic Silicon Oxide Overlayers.

Encapsulation of electrocatalysts and photocatalysts with semipermeable nanoscopic oxide overlayers that exhibit selective transport properties is an attractive approach to achieve high redox selectivity. However, defects within the overlayers─such as pinholes, cracks, or particle inclusions─may facilitate local high rates of parasitic reactions by creating pathways for facile transport of undesired reactants to exposed active sites. Scanning electrochemical microscopy (SECM) is an attractive method to determine the influence of defects on macroscopic performance metrics thanks to its ability to measure the relative rates of competing electrochemical reactions with high spatial resolution over the electrode.

Wet flue gas CO capture and utilization using one-dimensional metal-organic chains.

Herein, we describe the use of an ultramicroporous metal-organic framework (MOF) with a composition of [Ni(pzdc)(ade)(HO)]·(HO) (pzdc: 3,5-pyrazole dicarboxylic acid; ade: adenine), for the selective capture of carbon dioxide (CO) from wet flue gas followed by its conversion to value-added products. This MOF is comprised of one-dimensional Ni(II)-pyrazole dicarboxylate-adenine chains; through pi-pi stacking and H-bonding interactions, these one-dimensional chains stack into a three-dimensional supramolecular structure with a one-dimensional pore network. Upon heating, our MOF undergoes a color change from light blue to lavender, indicating a change in the coordination geometry of Ni(II).

Carbon-negative cement manufacturing from seawater-derived magnesium feedstocks.

This study describes and demonstrates key steps in a carbon-negative process for manufacturing cement from widely abundant seawater-derived magnesium (Mg) feedstocks. In contrast to conventional Portland cement, which starts with carbon-containing limestone as the source material, the proposed process uses membrane-free electrolyzers to facilitate the conversion of carbon-free magnesium ions (Mg) in seawater into magnesium hydroxide [Mg(OH)] precursors for the production of Mg-based cement. After a low-temperature carbonation curing step converts Mg(OH) into magnesium carbonates through reaction with carbon dioxide (CO), the resulting Mg-based binders can exhibit compressive strength comparable to that achieved by Portland cement after curing for only 2 days.

Mechanistic Study of Controlled Zinc Electrodeposition Behaviors Facilitated by Nanoscale Electrolyte Additives at the Electrode Interface.

Nanoparticle organic hybrid materials (NOHMs) are liquid-like materials composed of an inorganic core to which a polymeric canopy is ionically tethered. NOHMs have unique properties including negligible vapor pressure, high oxidative thermal stability, and the ability to bind to reactive species of interest due to the tunability of their polymeric canopy. This makes them promising multifunctional materials for a wide range of energy and environmental technologies, including electrolyte additives for electrochemical energy storage (e.

Nanoscale Hybrid Electrolytes with Viscosity Controlled Using Ionic Stimulus for Electrochemical Energy Conversion and Storage.

As renewable energy is rapidly integrated into the grid, the challenge has become storing intermittent renewable electricity. Technologies including flow batteries and CO conversion to dense energy carriers are promising storage options for renewable electricity. To achieve this technological advancement, the development of next generation electrolyte materials that can increase the energy density of flow batteries and combine CO capture and conversion is desired.

Electrochemical CO Reduction Reaction over Cu Nanoparticles with Tunable Activity and Selectivity Mediated by Functional Groups in Polymeric Binder.

The electrochemical carbon dioxide reduction reaction (CORR) using copper (Cu)-based catalysts has received significant attention mainly because Cu is an element capable of producing hydrocarbons and oxygenates. One possible way to control the CORR performance at the electrode interface is by modifying catalysts with specific functional groups of different polymeric binders, which are necessary components in the process of electrode fabrication. However, the modification effect of the key functional groups on the CORR activity and selectivity is poorly understood over Cu-based catalysts.

Compressed Sensing Image Reconstruction of Scanning Electrochemical Microscopy Measurements Carried Out at Ultrahigh Scan Speeds Using Continuous Line Probes.

Previous studies on scanning electrochemical microscopy (SECM) imaging with nonlocal continuous line probes (CLPs) have demonstrated the ability to increase areal imaging rates by an order of magnitude compared to SECM based on conventional ultramicroelectrode (UME) disk electrodes. Increasing the linear scan speed of the CLP during imaging presents an opportunity to increase imaging rates even further but results in a significant deterioration in image quality due to transport processes in the liquid electrolyte. Here, we show that compressed sensing (CS) postprocessing can be successfully applied to CLP-based SECM measurements to reconstruct images with minimal distortion at probe scan rates greatly exceeding the conventional SECM ″speed limit″.

CO utilization in built environment the swing carbonation of alkaline solid wastes with different mineralogy.

Carbon mineralization to solid carbonates is one of the reaction pathways that can not only utilize captured CO2 but also potentially store it in the long term. In this study, the dissolution and carbonation behaviors of alkaline solid wastes (i.e.

Electrochemical approaches for selective recovery of critical elements in hydrometallurgical processes of complex feedstocks.

Critical minerals are essential for the ever-increasing urban and industrial activities in modern society. The shift to cost-efficient and ecofriendly urban mining can be an avenue to replace the traditional linear flow of virgin-mined materials. Electrochemical separation technologies provide a sustainable approach to metal recovery, through possible integration with renewable energy, the minimization of external chemical input, as well as reducing secondary pollution.

Alkaline thermal treatment of seaweed for high-purity hydrogen production with carbon capture and storage potential.

Current thermochemical methods to generate H include gasification and steam reforming of coal and natural gas, in which anthropogenic CO emission is inevitable. If biomass is used as a source of H, the process can be considered carbon-neutral. Seaweeds are among the less studied types of biomass with great potential because they do not require freshwater.

Review of liquid nano-absorbents for enhanced CO capture.

Liquid nano-absorbents have become a topic of interest as a result of their enhanced mass-transfer performance for CO capture. They are believed to have revolutionized the conventional CO chemisorption process by largely improving CO capture kinetics and reducing the energy requirement for solvent regeneration. Two classes of nanomaterial-based CO capture absorbents, amine-based nanoparticle suspensions (nanofluids) and nanoparticle organic hybrid materials (NOHMs), have been developed, with significant progress achieved in recent decades.

Design and operation of a scanning electrochemical microscope for imaging with continuous line probes.

This article describes a home-built scanning electrochemical microscope capable of achieving high areal imaging rates through the use of continuous line probes (CLPs) and compressed sensing (CS) image reconstruction. The CLP is a nonlocal probe consisting of a band electrode, where the achievable spatial resolution is set by the thickness of the band and the achievable imaging rate is largely determined by its width. A combination of linear and rotational motors allows for CLP scanning at different angles over areas up to 25 cm to generate the raw signal necessary to reconstruct the desired electrochemical image using CS signal analysis algorithms.

Deconvoluting the Influences of 3D Structure on the Performance of Photoelectrodes for Solar-Driven Water Splitting.

Three-dimensionally (3D) structured photoelectrodes offer a number of potential benefits for solar fuels production compared to conventional planar photoelectrodes, including decreased optical losses, higher surface area for catalysis, easier removal of product species, and enhanced carrier collection efficiency. However, 3D structures can also present challenges, such as lower photovoltage and larger surface recombination. Quantifying and understanding the advantages and disadvantages of 3D structuring can maximize benefits, but this goal is not trivial because the factors that affect photoelectrode performance are intertwined.

Enhanced Performance of Si MIS Photocathodes Containing Oxide-Coated Nanoparticle Electrocatalysts.

Electrodepositing low loadings of metallic nanoparticle catalysts onto the surface of semiconducting photoelectrodes is a highly attractive approach for decreasing catalyst costs and minimizing optical losses. However, securely anchoring nanoparticles to the photoelectrode surface can be challenging-especially if the surface is covered by a thin insulating overlayer. Herein, we report on Si-based photocathodes for the hydrogen evolution reaction that overcome this problem through the use of a 2-10 nm thick layer of silicon oxide (SiO) that is deposited on top of Pt nanoparticle catalysts that were first electrodeposited on a 1.

Influence of methane emissions and vehicle efficiency on the climate implications of heavy-duty natural gas trucks.

While natural gas produces lower carbon dioxide emissions than diesel during combustion, if enough methane is emitted across the fuel cycle, then switching a heavy-duty truck fleet from diesel to natural gas can produce net climate damages (more radiative forcing) for decades. Using the Technology Warming Potential methodology, we assess the climate implications of a diesel to natural gas switch in heavy-duty trucks. We consider spark ignition (SI) and high-pressure direct injection (HPDI) natural gas engines and compressed and liquefied natural gas.

Morphological changes during enhanced carbonation of asbestos containing material and its comparison to magnesium silicate minerals.

The disintegration of asbestos containing materials (ACM) over time can result in the mobilization of toxic chrysotile ((Mg, Fe)3Si2O5(OH)4)) fibers. Therefore, carbonation of these materials can be used to alter the fibrous morphology of asbestos and help mitigate anthropogenic CO2 emissions, depending on the amount of available alkaline metal in the materials. A series of high pressure carbonation experiments were performed in a batch reactor at PCO2 of 139atm using solvents containing different ligands (i.