Converting CO2 To CO Research Articles

Self-assembled FeRu bimetallic nanocatalysts for efficient and durable mutual CO–CO2 conversion in a reversible solid oxide electrochemical cell

Self-assembled FeRu bimetallic nanocatalysts for efficient and durable mutual CO–CO2 conversion in a reversible solid oxide electrochemical cell

Designing and Engineering Atomically Dispersed Metal Catalysts for CO2 to CO Conversion: From Single to Dual Metal Sites.

The electrochemical CO2 reduction reaction (CO2 RR) is a promising approach to achieving sustainable electrical-to-chemical energy conversion and storage while decarbonizing the emission-heavy industry. The carbon-supported, nitrogen-coordinated, and atomically dispersed metal sites are effective catalysts for CO generation due to their high activity, selectivity, and earth abundance. Here, we discuss progress, challenges, and opportunities for designing and engineering atomic metal catalysts from single to dual metal sites. Engineering single metal sites using a nitrogen-doped carbon model was highlighted to exclusively study the effect of carbon particle sizes, metal contents, and M-N bond structures in the form of MN4 moieties on catalytic activity and selectivity. The structure-property correlation was analyzed by combining experimental results with theoretical calculations to uncover the CO2 to CO conversion mechanisms. Furthermore, dual-metal site catalysts, inheriting the merits of single-metal sites, have emerged as a new frontier due to their potentially enhanced catalytic properties. Designing optimal dual metal site catalysts could offer additional sites to alter the surface adsorption to CO2 and various intermediates, thus breaking the scaling relationship limitation and activity-stability trade-off. The CO2 RR electrolysis in flow reactors was discussed to provide insights into the electrolyzer design with improved CO2 utilization, reaction kinetics, and mass transport.

Functionally Graded Infiltration Triggering Ultrahigh Electrolytic Current in Robust Reversible Solid Oxide Cells

The reversible solid oxide cell (ReSOC) offers the dual capability to store electricity as chemical fuels and convert fuels to electricity, thereby enabling carbon neutral cycling. The nickel‐cermet fuel electrode exhibits high electrocatalytic activity for redox reactions while being particularly vulnerable to carbon deposition and nickel coarsening, especially at high current densities. Herein, a novel approach involving a graded infiltration onto a dendritic Ni–YSZ (yttria‐stabilized zirconia) skeleton with Pr6O11 nanoparticles/films is presented, demonstrating remarkable electrolytic current and coke tolerance in CO–CO2 conversion. At 800 °C, the current densities achieve approximately −2.0 and +2.0 A cm−2 under 1.3 and 0.6 V, respectively, showcasing robust cycling stability switching between two operational modes within 20 cycles. Notably, the attained electrolytic current density reaches an unprecedented −3.06 A cm−2 under 1.6 V. Furthermore, the button cell runs smoothly at ultrahigh electrolytic current densities ranging from −0.5 to −3.0 A cm−2 for nearly 270 h. The mechanism of high‐performance CO2 reduction is elucidated by in/ex situ experimental characterizations and theoretical calculations. These results indicate the viability of employing Ni–YSZ‐supported ReSOC for stable renewable electricity storage at previously unattainable reaction rates, and have implications for fundamental understanding of designing robust ReSOC based on the nickel‐cermet fuel electrode.

Tailoring the catalytic activity and selectivity on CO2 to C1 products by the synergistic effect of reactive molecules: A DFT study

The conversion of CO2 to CO is one of the crucial pathways in the carbon dioxide reduction reaction (CO2RR). Iron and nitrogen co-doped carbon matrix (FeN4) is a promising catalyst for converting CO2to CO with excellent activity and selectivity. However, the reactive mechanism of CO2RR on the FeN4 catalyst is not fully unveiled. For example, it is still evasive that the obtained C1 product is methanol and/or methane instead of CO in some cases. Herein, DFT calculation is conducted to unravel the effect from both solvent molecules and intermediates as axial groups on the selectivity of C1 products in CO2RR using FeN4 catalyts. Calculation results demonstrate that the FeN4(H), FeN4(OH), FeN4(COOH), and FeN4(CO) configurations are not only beneficial to the removal of CO, but also effectively suppress the hydrogen evolution reaction, whereas the FeN4, FeN4(CO2) and FeN4(H2O) configurations are inclined to produce CH3OH and/or CH4. The mechanism studied in this work provides an inspiration of optimizing the selectivity of C1 products in CO2RR from the perspective of regulating solvent molecules and intermediates as axial groups on FeN4.

Phosphorus Tailors thed‐Band Center of Copper Atomic Sites for Efficient CO2Photoreduction under Visible‐Light Irradiation

AbstractPhotoreduction of CO2into solar fuels has received great interest, but suffers from low catalytic efficiency and poor selectivity. Herein, two single‐Cu‐atom catalysts with unique Cu configurations in phosphorus‐doped carbon nitride (PCN), namely, Cu1N3@PCN and Cu1P3@PCN were fabricated via selective phosphidation, and tested in visible light‐driven CO2reduction by H2O without sacrificial agents. Cu1N3@PCN was exclusively active for CO production with a rate of 49.8 μmolCO gcat−1 h−1, outperforming most polymeric carbon nitride (C3N4) based catalysts, while Cu1P3@PCN preferably yielded H2. Experimental and theoretical analysis suggested that doping P in C3N4by replacing a corner C atom upshifted thed‐band center of Cu in Cu1N3@PCN close to the Fermi level, which boosted the adsorption and activation of CO2on Cu1N3, making Cu1N3@PCN efficiently convert CO2to CO. In contrast, Cu1P3@PCN with a much lower Cu3delectron energy exhibited negligible CO2adsorption, thereby preferring H2formation via photocatalytic H2O splitting.

Investigation of Cyclam Based Re‐Complexes as Potential Electrocatalysts for the CO2Reduction Reaction

AbstractAmong the various homogenous electrocatalysts, especially Re(bpy)(CO)3Cl and [Ni(cyclam)]2+were shown to be highly efficient for the selective conversion of CO2to CO at moderate potentials. However, a purposeful combination of a ReItricarbonyl unit with a cyclam ligand hitherto received no attention. Herein, we report on a series of cyclam based Re complexes comprising the original {N4} as well as heteroatom‐altered ligand frameworks, describe their synthesis, reveal their coordination behavior and furthermore investigate their performance towards the electrochemical CO2reduction.

Niobium Nitride Catalyst for Electrocatalytic Reduction of CO 2

Converting CO2 to CO by electrochemical method is considered as an economic and friendly strategy to solve problems of resource and environment. In this work, precursor of niobium/carbon was prepared by wet chemical method and converted into Nb4N5/C and Nb2O5/C after calcination under NH3 and Ar respectively. When the nitriding temperature reaches to 700℃, prepared Nb4N5/C exhibits excellent catalytic activity with CO Faradaic efficiency of 57% at -0.83 V vs RHE in CO2 saturated 0.5 mol·L-1 NaCl solution. The results show that the catalytic activity of Nb4N5/C is related to the N doping in Nb4N5.

A spongy nickel-organic CO2 reduction photocatalyst for nearly 100% selective CO production.

Solar-driven photocatalytic conversion of CO2 into fuels has attracted a lot of interest; however, developing active catalysts that can selectively convert CO2 to fuels with desirable reaction products remains a grand challenge. For instance, complete suppression of the competing H2 evolution during photocatalytic CO2-to-CO conversion has not been achieved before. We design and synthesize a spongy nickel-organic heterogeneous photocatalyst via a photochemical route. The catalyst has a crystalline network architecture with a high concentration of defects. It is highly active in converting CO2 to CO, with a production rate of ~1.6 × 104 μmol hour-1 g-1. No measurable H2 is generated during the reaction, leading to nearly 100% selective CO production over H2 evolution. When the spongy Ni-organic catalyst is enriched with Rh or Ag nanocrystals, the controlled photocatalytic CO2 reduction reactions generate formic acid and acetic acid. Achieving such a spongy nickel-organic photocatalyst is a critical step toward practical production of high-value multicarbon fuels using solar energy.

Rapid formation of self-organised Ag nanosheets with high efficiency and selectivity in CO2electroreduction to CO

Rapid formation of hierarchical AgCl nanosheets is achieved through rational optimization of anodisation parameters. The electroreduced halide-derived Ag nanosheets exhibit excellent performance with a ∼95% CO2to CO conversion efficiency at an overpotential as low as 0.29 V.