Scaling CO Electrolyzer Cell Area from Bench to Pilot.

To contribute meaningfully to carbon dioxide (CO) emissions reduction, CO electrolyzer technology will need to scale immensely. Bench-scale electrolyzers are the norm, with active areas <5 cm. However, cell areas on the order of 100s or 1000s of cm will be required for industrial deployment.

Early Warning for the Electrolyzer: Monitoring CO Reduction via In-Line Electrochemical Impedance Spectroscopy.

The electrochemical CO reduction reaction (CO RR) to fuels and feedstocks presents an opportunity to decarbonize the chemical industry, and current electrolyzer performance levels approach commercial viability. However, stability remains below that required, in part because of the challenge of probing these electrolyzer systems in real time and the challenge of determining the root cause of failure. Failure can result from initial conditions (e.

Bipolar membrane electrolyzers enable high single-pass CO electroreduction to multicarbon products.

In alkaline and neutral MEA CO electrolyzers, CO rapidly converts to (bi)carbonate, imposing a significant energy penalty arising from separating CO from the anode gas outlets. Here we report a CO electrolyzer uses a bipolar membrane (BPM) to convert (bi)carbonate back to CO, preventing crossover; and that surpasses the single-pass utilization (SPU) limit (25% for multi-carbon products, C) suffered by previous neutral-media electrolyzers. We employ a stationary unbuffered catholyte layer between BPM and cathode to promote C products while ensuring that (bi)carbonate is converted back, in situ, to CO near the cathode.

Concentrated Ethanol Electrosynthesis from CO via a Porous Hydrophobic Adlayer.

Electrochemical CO reduction can convert waste emissions into dense liquid fuels compatible with existing energy infrastructure. High-rate electrocatalytic conversion of CO to ethanol has been achieved in membrane electrode assembly (MEA) electrolyzers; however, ethanol produced at the cathode is transported, via electroosmotic drag and diffusion, to the anode, where it is diluted and may be oxidized. The ethanol concentrations that result on both the cathodic and anodic sides are too low to justify the energetic and financial cost of downstream separation.

Low coordination number copper catalysts for electrochemical CO methanation in a membrane electrode assembly.

The electrochemical conversion of CO to methane provides a means to store intermittent renewable electricity in the form of a carbon-neutral hydrocarbon fuel that benefits from an established global distribution network. The stability and selectivity of reported approaches reside below technoeconomic-related requirements. Membrane electrode assembly-based reactors offer a known path to stability; however, highly alkaline conditions on the cathode favour C-C coupling and multi-carbon products.

Enhanced multi-carbon alcohol electroproduction from CO via modulated hydrogen adsorption.

Multi-carbon alcohols such as ethanol are valued as fuels in view of their high energy density and ready transport. Unfortunately, the selectivity toward alcohols in CO/CO electroreduction is diminished by ethylene production, especially when operating at high current densities (>100 mA cm). Here we report a metal doping approach to tune the adsorption of hydrogen at the copper surface and thereby promote alcohol production.

Efficient Methane Electrosynthesis Enabled by Tuning Local CO Availability.

The electroreduction of carbon dioxide (CORR) to valuable chemicals is a promising avenue for the storage of intermittent renewable electricity. Renewable methane, obtained via CORR using renewable electricity as energy input, has the potential to serve as a carbon-neutral fuel or chemical feedstock, and it is of particular interest in view of the well-established infrastructure for its storage, distribution, and utilization. However, CORR to methane still suffers from low selectivity at commercially relevant current densities (>100 mA cm).

Efficient upgrading of CO to C fuel using asymmetric C-C coupling active sites.

The electroreduction of C feedgas to high-energy-density fuels provides an attractive avenue to the storage of renewable electricity. Much progress has been made to improve selectivity to C and C products, however, the selectivity to desirable high-energy-density C products remains relatively low. We reason that C electrosynthesis relies on a higher-order reaction pathway that requires the formation of multiple carbon-carbon (C-C) bonds, and thus pursue a strategy explicitly designed to couple C with C intermediates.

Molecular tuning of CO-to-ethylene conversion.

The electrocatalytic reduction of carbon dioxide, powered by renewable electricity, to produce valuable fuels and feedstocks provides a sustainable and carbon-neutral approach to the storage of energy produced by intermittent renewable sources. However, the highly selective generation of economically desirable products such as ethylene from the carbon dioxide reduction reaction (CORR) remains a challenge. Tuning the stabilities of intermediates to favour a desired reaction pathway can improve selectivity, and this has recently been explored for the reaction on copper by controlling morphology, grain boundaries, facets, oxidation state and dopants.

Dopant-tuned stabilization of intermediates promotes electrosynthesis of valuable C3 products.

The upgrading of CO/CO feedstocks to higher-value chemicals via energy-efficient electrochemical processes enables carbon utilization and renewable energy storage. Substantial progress has been made to improve performance at the cathodic side; whereas less progress has been made on improving anodic electro-oxidation reactions to generate value. Here we report the efficient electroproduction of value-added multi-carbon dimethyl carbonate (DMC) from CO and methanol via oxidative carbonylation.

Electrochemical CO Reduction into Chemical Feedstocks: From Mechanistic Electrocatalysis Models to System Design.

The electrochemical reduction of CO is a promising route to convert intermittent renewable energy to storable fuels and valuable chemical feedstocks. To scale this technology for industrial implementation, a deepened understanding of how the CO reduction reaction (CO RR) proceeds will help converge on optimal operating parameters. Here, a techno-economic analysis is presented with the goal of identifying maximally profitable products and the performance targets that must be met to ensure economic viability-metrics that include current density, Faradaic efficiency, energy efficiency, and stability.

CO electroreduction to ethylene via hydroxide-mediated copper catalysis at an abrupt interface.

Carbon dioxide (CO) electroreduction could provide a useful source of ethylene, but low conversion efficiency, low production rates, and low catalyst stability limit current systems. Here we report that a copper electrocatalyst at an abrupt reaction interface in an alkaline electrolyte reduces CO to ethylene with 70% faradaic efficiency at a potential of -0.55 volts versus a reversible hydrogen electrode (RHE).

Hydronium-Induced Switching between CO Electroreduction Pathways.

Over a broad range of operating conditions, many CO electroreduction catalysts can maintain selectivity toward certain reduction products, leading to materials and surfaces being categorized according to their products; here we ask, is product selectivity truly a property of the catalyst? Silver is among the best electrocatalysts for CO in aqueous electrolytes, where it reaches near-unity selectivity. We consider the hydrogenations of the oxygen and carbon atoms via the two proton-coupled-electron-transfer processes as chief determinants of product selectivity; and find using density functional theory (DFT) that the hydronium (HO) intermediate plays a key role in the first oxygen hydrogenation step and lowers the activation energy barrier for CO formation. When this hydronium influence is removed, the activation energy barrier for oxygen hydrogenation increases significantly, and the barrier for carbon hydrogenation is reduced.

Rapid prototyping of all-solution-processed multi-lengthscale electrodes using polymer-induced thin film wrinkling.

Three-dimensional electrodes that are controllable over multiple lengthscales are very important for use in bioanalytical systems that integrate solid-phase devices with solution-phase samples. Here we present a fabrication method based on all-solution-processing and thin film wrinkling using smart polymers that is ideal for rapid prototyping of tunable three-dimensional electrodes and is extendable to large volume manufacturing. Although all-solution-processing is an attractive alternative to vapor-based techniques for low-cost manufacturing of electrodes, it often results in films suffering from low conductivity and poor substrate adhesion.

Programmable Wrinkling of Self-Assembled Nanoparticle Films on Shape Memory Polymers.

Hierarchically structured materials, inspired by sophisticated structures found in nature, are finding increasing applications in a variety of fields. Here, we describe the fabrication of wrinkled gold nanoparticle films, which leverage the structural tunability of gold nanoparticles to program the wavelength and amplitude of gold wrinkles. We have carefully examined the structural evolution and tuning of these wrinkled surfaces through varying nanoparticle parameters (diameter, number of layers, density) and substrate parameters (number of axes constrained during wrinkling) through scanning electron microscopy and cross-sectional transmission electron microscopy.

Rapidly prototyped multi-scale electrodes to minimize the voltage requirements for bacterial cell lysis.

Lab-on-a-chip systems used for nucleic acid based detection of bacteria rely on bacterial lysis for the release of cellular material. Although electrical lysis devices can be miniaturized for on-chip integration and reagent-free lysis, they often suffer from high voltage requirements, and rely on the use of off-chip voltage supplies. To overcome this barrier, we developed a rapid prototyping method for creating multi-scale electrodes that are structurally tuned for lowering the voltage needed for electrical bacterial lysis.

Prototyping of wrinkled nano-/microstructured electrodes for electrochemical DNA detection.

Biosensing platforms are ideal for addressing the diagnostic needs of resource-poor areas; however, the translation of such systems from the laboratory to the point-of-need has been a slow process. Rapid prototyping methods that enable an application-specific biosensor to be created in a matter of hours from design to fabrication would expedite the clinical and field testing of such systems. Here, we demonstrate a benchtop method based on craft cutting and polymer-induced wrinkling for creating multiplexed electrochemical DNA biosensors.

An algorithm to discover gene signatures with predictive potential.

Background: The advent of global gene expression profiling has generated unprecedented insight into our molecular understanding of cancer, including breast cancer. For example, human breast cancer patients display significant diversity in terms of their survival, recurrence, metastasis as well as response to treatment. These patient outcomes can be predicted by the transcriptional programs of their individual breast tumors.