Electroreduction of CO to 2.8 A cm⁻ C Products: Maximizing Efficiency with Minimalist Electrode Design Featuring a Mesopore-Rich Hydrophobic Copper Catalyst Layer.

This work shows how hydrophobicity and porosity can be incorporated into copper catalyst layers (CLs) for the efficient electroreduction of CO (CORR) in a flow cell. Oxide-derived (OD) Cu catalysts are synthesized using K and Cs as templates, termed respectively as OD-Cu-K and OD-Cu-Cs. CLs, assembled from OD-Cu-K and OD-Cu-Cs, exhibit enhanced CORR performance compared to "unmodified" OD-Cu CL.

Direct Electroreduction of Carbonate to Formate.

A cause of losses in energy and carbon conversion efficiencies during the electrochemical CO reduction reaction (eCORR) can be attributed to the formation of carbonates (CO), which is generally considered to be an electrochemically inert species. Herein, using Raman spectroscopy, liquid chromatography, H nuclear magnetic resonance spectroscopy, C and deuterium isotope labeling, and density functional theory simulations, we show that carbonate intermediates are adsorbed on a copper electrode during eCORR in KHCO electrolyte from 0.2 to -1.

NMR-based quantification of liquid products in CO electroreduction on phosphate-derived nickel catalysts.

Recently discovered phosphate-derived Ni catalysts have opened a new pathway towards multicarbon products via CO electroreduction. However, understanding the influence of basic parameters such as electrode potential, pH, and buffer capacity is needed for optimized C product formation. To this end, rigorous catalyst evaluation and sensitive analytical tools are required to identify potential new products and minimize increasing quantification errors linked to long-chain carbon compounds.

Enhanced Carbon Monoxide Electroreduction to >1 A cm C Products Using Copper Catalysts Dispersed on MgAl Layered Double Hydroxide Nanosheet House-of-Cards Scaffolds.

Cu catalysts are most apt for reducing CO to multi-carbon products in aqueous electrolytes. To enhance the product yield, we can increase the overpotential and the catalyst mass loading. However, these approaches can cause inadequate mass transport of CO to the catalytic sites, which will then lead to H evolution dominating the product selectivity.

Surface charge as activity descriptors for electrochemical CO reduction to multi-carbon products on organic-functionalised Cu.

Intensive research in electrochemical CO reduction reaction has resulted in the discovery of numerous high-performance catalysts selective to multi-carbon products, with most of these catalysts still being purely transition metal based. Herein, we present high and stable multi-carbon products selectivity of up to 76.6% across a wide potential range of 1 V on histidine-functionalised Cu.

Surface Water as an Initial Proton Source for the Electrochemical CO Reduction Reaction on Copper Surfaces.

We have employed in situ electrochemical shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) and density functional theory (DFT) calculations to study the CO reduction reaction (CORR) on Cu single-crystal surfaces under various conditions. Coadsorbed and structure-/potential-dependent surface species, including *CO, Cu-O , and Cu-OH , were identified using electrochemical spectroscopy and isotope labeling. The relative abundance of *OH follows a "volcano" trend with applied potentials in aqueous solutions, which is yet absent in absolute alcoholic solutions.

Production of C -C Acetate Esters via CO Electroreduction in a Membrane Electrode Assembly Cell.

Electrocatalytic carbon monoxide reduction has been previously reported to yield a range of carbonaceous products including alcohols, hydrocarbons and carboxylic acids. However, esters, an important family of organic compounds, have not been formed. Herein, we report the electrosynthesis of C to C acetate esters (H C-(C=O)-O-R) from carbon monoxide using copper catalysts in a membrane electrode assembly cell.

Polaron Delocalization Dependence of the Conductivity and the Seebeck Coefficient in Doped Conjugated Polymers.

Conjugated polymers are promising materials for thermoelectrics as they offer good performances at near ambient temperatures. The current focus on polymer thermoelectric research mainly targets a higher power factor (PF; a product of the conductivity and square of the Seebeck coefficient) through improving the charge mobility. This is usually accomplished structural modification in conjugated polymers using different processing techniques and doping.

Mechanistic Insights into the Selective Electroreduction of Crotonaldehyde to Crotyl Alcohol and 1-Butanol.

The electroreduction of crotonaldehyde, which can be derived from the aldol condensation of acetaldehyde (sustainably produced from CO reduction or from biomass ethanol), is potentially a carbon-neutral route for generating high-value C chemicals such as crotyl alcohol and 1-butanol. Developing functional catalysts is necessary toward this end. Herein, the electrocatalytic conversion of crotonaldehyde to crotyl alcohol and 1-butanol was achieved in 0.

Selectivity Map for the Late Stages of CO and CO Reduction to C Species on Copper Electrodes.

The electrochemical CO and CO reduction reactions (CORR and CO RR) using copper catalysts and renewable electricity hold promise as a carbon-neutral route to produce commodity chemicals and fuels. However, the exact mechanisms and structure sensitivity of Cu electrodes toward C products are still under debate. Herein, we investigate ethylene oxide reduction (EOR) as a proxy to the late stages of CORR to ethylene, and the results are compared to those of acetaldehyde reduction to ethanol.

Electrochemical Reduction of Carbon Dioxide to 1-Butanol on Oxide-Derived Copper.

The electroreduction of carbon dioxide using renewable electricity is an appealing strategy for the sustainable synthesis of chemicals and fuels. Extensive research has focused on the production of ethylene, ethanol and n-propanol, but more complex C molecules have been scarcely reported. Herein, we report the first direct electroreduction of CO to 1-butanol in alkaline electrolyte on Cu gas diffusion electrodes (Faradaic efficiency=0.

Enhanced Electroreduction of Carbon Dioxide to Methanol Using Zinc Dendrites Pulse-Deposited on Silver Foam.

The electrocatalytic CO reduction reaction (CO RR) can dynamise the carbon cycle by lowering anthropogenic CO emissions and sustainably producing valuable fuels and chemical feedstocks. Methanol is arguably the most desirable C product of CO RR, although it typically forms in negligible amounts. In our search for efficient methanol-producing CO RR catalysts, we have engineered Ag-Zn catalysts by pulse-depositing Zn dendrites onto Ag foams (PD-Zn/Ag foam).

Mechanistic Study of the Synergy between Iron and Transition Metals for the Catalysis of the Oxygen Evolution Reaction.

A comprehensive study of the synergy between Fe and six transition metals (M=Ti, Co, Ni, Cu, Ag, Au), and how their M-Fe oxides electrocatalyze the oxygen evolution reaction (OER) was undertaken. Measurements were made using metal disks as the working electrodes and the addition of Fe ions to the 1 m KOH electrolyte. The surfaces of the metal disks were oxidized after the OER.

On the Role of Sulfur for the Selective Electrochemical Reduction of CO to Formate on CuS Catalysts.

The efficient electroreduction of CO has received significant attention as it is one of the crucial means to develop a closed-loop anthropogenic carbon cycle. Here, we describe the mechanistic workings of an electrochemically deposited CuS catalyst that can reduce CO to formate with a Faradaic efficiency (FE) of 75% and geometric current density ( j) of -9.0 mA/cm at -0.

Effects of Electrolyte Anions on the Reduction of Carbon Dioxide to Ethylene and Ethanol on Copper (100) and (111) Surfaces.

The CO electroreduction reaction has been investigated on Cu(100) and Cu(111) surfaces in 0.1 m aqueous solutions of KClO , KCl, KBr, and KI electrolyte. The formation of ethylene and ethanol on these surfaces generally increased as the electrolyte anion was changed from ClO →Cl →Br →I .

The effects of currents and potentials on the selectivities of copper toward carbon dioxide electroreduction.

Copper electrodes have been shown to be selective toward the electroreduction of carbon dioxide to ethylene, carbon monoxide, or formate. However, the underlying causes of their activities, which have been attributed to a rise in local pH near the surface of the electrode, presence of atomic-scale defects, and/or residual oxygen atoms in the catalysts, etc., have not been generally agreed on.

Investigating the Role of Copper Oxide in Electrochemical CO Reduction in Real Time.

Copper oxides have been of considerable interest as electrocatalysts for CO reduction (CO2R) in aqueous electrolytes. However, their role as an active catalyst in reducing the required overpotential and improving the selectivity of reaction compared with that of polycrystalline copper remains controversial. Here, we introduce the use of selected-ion flow tube mass spectrometry, in concert with chronopotentiometry, in situ Raman spectroscopy, and computational modeling, to investigate CO2R on CuO nanoneedles, CuO nanocrystals, and CuO nanoparticles.

Ruthenium-Tungsten Composite Catalyst for the Efficient and Contamination-Resistant Electrochemical Evolution of Hydrogen.

A new catalyst, prepared by a simple physical mixing of ruthenium (Ru) and tungsten (W) powders, has been discovered to interact synergistically to enhance the electrochemical hydrogen evolution reaction (HER). In an aqueous 0.5 M HSO electrolyte, this catalyst, which contained a miniscule loading of 2-5 nm sized Ru nanoparticles (5.

Rational Design of Sulfur-Doped Copper Catalysts for the Selective Electroreduction of Carbon Dioxide to Formate.

The selective electroreduction of CO to formate (or formic acid) is of great interest in the field of renewable-energy utilization. In this work, we designed a sulfur-doped Cu O-derived Cu catalyst and showed that the presence of sulfur can tune the selectivity of Cu significantly from the production of various CO reduction products to almost exclusively formate. Sulfur is doped into the Cu catalysts by dipping the Cu substrates into ammonium polysulfide solutions.

Investigating synergistic interactions of group 4, 5 and 6 metals with gold nanoparticles for the catalysis of the electrochemical hydrogen evolution reaction.

An investigation of the catalysis of the electrochemical hydrogen evolution reaction (HER, 2H + 2e → H) in aqueous 0.5 M HSO electrolyte using composites consisting of gold nanoparticles (Au), carbon (Black Pearl 2000) and group 4, 5, and 6 metals is presented. This study is a continuation of our earlier work (Phys.

Interface confined hydrogen evolution reaction in zero valent metal nanoparticles-intercalated molybdenum disulfide.

Interface confined reactions, which can modulate the bonding of reactants with catalytic centres and influence the rate of the mass transport from bulk solution, have emerged as a viable strategy for achieving highly stable and selective catalysis. Here we demonstrate that 1T'-enriched lithiated molybdenum disulfide is a highly powerful reducing agent, which can be exploited for the in-situ reduction of metal ions within the inner planes of lithiated molybdenum disulfide to form a zero valent metal-intercalated molybdenum disulfide. The confinement of platinum nanoparticles within the molybdenum disulfide layered structure leads to enhanced hydrogen evolution reaction activity and stability compared to catalysts dispersed on carbon support.

Enhanced catalysis of the electrochemical hydrogen evolution reaction using composites of molybdenum-based compounds, gold nanoparticles and carbon.

Molybdenum nitride has been recently reported to interact synergistically with gold to show an enhanced activity for the electrochemical hydrogen evolution reaction (2H(+) + 2e(-)→ H2, HER). In this work, we elucidated the roles of nitrogen, carbon, molybdenum and gold on this observed phenomenon. Composites of Mo-based compounds, carbon black (black pearl 2000) and/or Au nanoparticles (AuNP) were prepared, and their activities for the HER in a 0.

Efficient and Stable Evolution of Oxygen Using Pulse-Electrodeposited Ir/Ni Oxide Catalyst in Fe-Spiked KOH Electrolyte.

Metal oxides have been extensively explored as catalysts for the electrochemical oxygen evolution reaction (OER). Here, we present an excellent OER catalytic system consisting of pulse-electrodeposited Ir/Ni oxides in Fe(3+)-spiked 1 M KOH. In pure 1 M KOH electrolyte, the optimized catalyst, which had an Ir:Ni atom ratio of 1:1.