Self-assembled monolayer of 2-pyridinethiol@Pt-Au nanoparticles, a new electrocatalyst for reducing of CO2 to methanol

Structure-Tailored Surface Oxide on Cu-Ga Intermetallics Enhances CO2 Reduction Selectivity to Methanol at Ultralow Potential

Electrochemical CO₂ reduction reaction (eCO₂ RR) is performed on two intermetallic compounds formed by copper and gallium metals (CuGa₂ and Cu₉ Ga₄ ). Among them, CuGa₂ selectively converts CO₂ to methanol with remarkable Faradaic efficiency of 77.26% at an extremely low potential of -0.3 V vs RHE. The high performance of CuGa₂ compared to Cu₉ Ga₄ is driven by its unique 2D structure, which retains surface and subsurface oxide species (Ga₂ O₃ ) even in the reduction atmosphere. The Ga₂ O₃ species is mapped by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) techniques and electrochemical measurements. The eCO₂ RR selectivity to methanol are decreased at higher potential due to the lattice expansion caused by the reduction of the Ga₂ O₃ , which is probed by in situ XAFS, quasi in situ powder X-ray diffraction, and ex situ XPS measurements. The mechanism of the formation of methanol is visualized by in situ infrared (IR) spectroscopy and the source of the carbon of methanol at the molecular level is confirmed from the isotope-labeling experiments in presence of ¹³ CO₂ . Finally, to minimize the mass transport limitations and improve the overall eCO₂ RR performance, a poly(tetrafluoroethylene)-based gas diffusion electrode is used in the flow cell configuration.

In situ dual doping for constructing efficient CO2-to-methanol electrocatalysts

Methanol is a highly desirable product of CO₂ electroreduction due to its wide array of industrial applications. However, the development of CO₂-to-methanol electrocatalysts with high performance is still challenging. Here we report an operationally simple in situ dual doping strategy to construct efficient CO₂-to-methanol electrocatalysts. In particular, when using Ag,S-Cu₂O/Cu as electrocatalyst, the methanol Faradaic efficiency (FE) could reach 67.4% with a current density as high as 122.7 mA cm^-2 in an H-type cell using 1-butyl-3-methylimidazolium tetrafluoroborate/H₂O as the electrolyte, while the current density was below 50 mA cm^-2 when the FE was greater than 50% over the reported catalysts. Experimental and theoretical studies suggest that the anion S can effectively adjust the electronic structure and morphology of the catalysts in favor of the methanol pathway, whereas the cation Ag suppresses the hydrogen evolution reaction. Their synergistic interactions with host material enhance the selectivity and current density for methanol formation. This work opens a way for designing efficient catalysts for CO₂ electroreduction to methanol.

Recent Advances in Catalyst Structure and Composition Engineering Strategies for Regulating CO2 Electrochemical Reduction

Electrochemical CO₂ reduction has been recognized as a promising solution in tackling energy- and environment-related challenges of human society. In the past few years, the rapid development of advanced electrocatalysts has significantly improved the efficiency of this reaction and accelerated the practical applications of this technology. Herein, representative catalyst structures and composition engineering strategies in regulating the CO₂ reduction selectivity and activity toward various products including carbon monoxide, formate, methane, methanol, ethylene, and ethanol are summarized. An overview of in situ/operando characterizations and advanced computational modeling in deepening the understanding of the reaction mechanisms and accelerating catalyst design are also provided. To conclude, future challenges and opportunities in this research field are discussed.

Towards Solar Methanol: Past, Present, and Future

This work aims to provide an overview of producing value-added products affordably and sustainably from greenhouse gases (GHGs). Methanol (MeOH) is one such product, and is one of the most widely used chemicals, employed as a feedstock for ≈30% of industrial chemicals. The starting materials are analogous to those feeding natural processes: water, CO2, and light. Innovative technologies from this effort have global significance, as they allow GHG recycling, while providing society with a renewable carbon feedstock. Light, in the form of solar energy, assists the production process in some capacity. Various solar strategies of continually increasing technology readiness levels are compared to the commercial MeOH process, which uses a syngas feed derived from natural gas. These strategies include several key technologies, including solar-thermochemical, photochemical, and photovoltaic-electrochemical. Other solar-assisted technologies that are not yet commercial-ready are also discussed. The commercial-ready technologies are compared using a technoeconomic analysis, and the scalability of solar reactors is also discussed in the context of light-incorporating catalyst architectures and designs. Finally, how MeOH compares against other prospective products is briefly discussed, as well as the viability of the most promising solar MeOH strategy in an international context.