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1. Sustainedly High‐Rate Electroreduction of CO ₂ to Multi‐Carbon Products on Nickel Oxygenate/Copper Interfacial Catalysts

   https://doi.org/10.1002/aenm.202400827  

   Mao, Xuejiao; Chang, Chun‐Wai; Li, Zhiguo; Han, Zishan; Gao, Jiachen; Lyons, Mason; Sterbinsky, George; Guo, Yong; Zhang, Bo; Wang, Yaogang; et al (July 2024, Advanced Energy Materials)

   Abstract Copper (Cu) is the most attractive electrocatalyst for CO₂reduction to multi‐carbon (C₂₊) products with high economic value in considerable amounts. However, the rational design of a structurally stable Cu‐based catalyst that can achieve high activity and stability towards C₂₊products remain a grand challenge. Here, a highly stable nickel oxygenate/Cu electrocatalyst is developed with abundant NiOOH/Cu interfaces by in situ electrochemical reconstruction. The nickel oxygenate/Cu electrocatalyst achieves a superior Faradaic efficiency of 86.3 ± 3.0% and a record partial current density of 2085 A g⁻¹for C₂₊products with long‐term stability. In situ experimental and theoretical studies demonstrates that the exceptional performance in generating C₂₊products is attributed to the presence of the NiOOH/Cu interfaces which increase *CO coverage, lower energy barrier for *CO coupling and stabilize *OCCO simultaneously. This work provides new insights into the rational design of electrocatalysts to achieve stable and efficient electrocatalytic CO₂reduction capabilities. 

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2. Cu dimer anchored on C ₂ N monolayer: low-cost and efficient Bi-atom catalyst for CO oxidation

   https://doi.org/10.1039/C8NR03394C  

   Li, Fengyu; Chen, Zhongfang (January 2018, Nanoscale)

   By means of density functional theory (DFT) computations, we systemically investigated CO/O 2 adsorption and CO oxidation pathways on a bi-atom catalyst, namely, a copper dimer anchored on a C 2 N monolayer (Cu 2 @C 2 N), and we compared it with its monometallic counterpart Cu 1 @C 2 N. The Cu dimer could be stably embedded into the porous C 2 N monolayer. The reactions between the adsorbed O 2 and CO via both bi-molecular and tri-molecular Langmuir–Hinshelwood (L–H) and Eley–Rideal (E–R) mechanisms were comparably studied, and we found that the bi-atom catalyst Cu 2 @C 2 N possessed superior performance toward CO oxidation as compared to the single-atom catalyst Cu 1 @C 2 N. Our comparative study suggested that the newly predicted bi-atom catalyst, i.e. , a copper dimer anchored on a suitable support is highly active for CO oxidation, which can provide a useful guideline for further developing highly effective and low-cost green nanocatalysts. 

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3. 2D Copper Tetrahydroxyquinone Conductive Metal–Organic Framework for Selective CO ₂ Electrocatalysis at Low Overpotentials

   https://doi.org/10.1002/adma.202004393  

   Majidi, Leily; Ahmadiparidari, Alireza; Shan, Nannan; Misal, Saurabh_N; Kumar, Khagesh; Huang, Zhehao; Rastegar, Sina; Hemmat, Zahra; Zou, Xiaodong; Zapol, Peter; et al (February 2021, Advanced Materials)

   Abstract Metal–organic frameworks (MOFs) are promising materials for electrocatalysis; however, lack of electrical conductivity in the majority of existing MOFs limits their effective utilization in the field. Herein, an excellent catalytic activity of a 2D copper (Cu)‐based conductive MOF, copper tetrahydroxyquinone (CuTHQ), is reported for aqueous CO₂reduction reaction (CO₂RR) at low overpotentials. It is revealed that CuTHQ nanoflakes (NFs) with an average lateral size of 140 nm exhibit a negligible overpotential of 16 mV for the activation of this reaction, a high current density of ≈173 mA cm⁻²at −0.45 V versus RHE, an average Faradaic efficiency (F.E.) of ≈91% toward CO production, and a remarkable turnover frequency as high as ≈20.82 s⁻¹. In the low overpotential range, the obtained CO formation current density is more than 35 and 25 times higher compared to state‐of‐the‐art MOF and MOF‐derived catalysts, respectively. The operando Cu K‐edge X‐ray absorption near edge spectroscopy and density functional theory calculations reveal the existence of reduced Cu (Cu⁺) during CO₂RR which reversibly returns to Cu²⁺after the reaction. The outstanding CO₂catalytic functionality of conductive MOFs (c‐MOFs) can open a way toward high‐energy‐density electrochemical systems. 

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4. Dual-site catalysts featuring platinum-group-metal atoms on copper shapes boost hydrocarbon formations in electrocatalytic CO2 reduction

   https://doi.org/10.1038/s41467-023-38777-y  

   Chhetri, Manjeet; Wan, Mingyu; Jin, Zehua; Yeager, John; Sandor, Case; Rapp, Conner; Wang, Hui; Lee, Sungsik; Bodenschatz, Cameron J.; Zachman, Michael J.; et al (May 2023, Nature Communications)

   Abstract Copper-based catalyst is uniquely positioned to catalyze the hydrocarbon formations through electrochemical CO₂reduction. The catalyst design freedom is limited for alloying copper with H-affinitive elements represented by platinum group metals because the latter would easily drive the hydrogen evolution reaction to override CO₂reduction. We report an adept design of anchoring atomically dispersed platinum group metal species on both polycrystalline and shape-controlled Cu catalysts, which now promote targeted CO₂reduction reaction while frustrating the undesired hydrogen evolution reaction. Notably, alloys with similar metal formulations but comprising small platinum or palladium clusters would fail this objective. With an appreciable amount of CO-Pd₁moieties on copper surfaces, facile CO^*hydrogenation to CHO^*or CO-CHO^*coupling is now viable as one of the main pathways on Cu(111) or Cu(100) to selectively produce CH₄or C₂H₄through Pd-Cu dual-site pathways. The work broadens copper alloying choices for CO₂reduction in aqueous phases. 

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5. Methane Over‐Oxidation by Extra‐Framework Copper‐Oxo Active Sites of Copper‐Exchanged Zeolites: Crucial Role of Traps for the Separated Methyl Group

   https://doi.org/10.1002/cphc.202100103  

   Adeyiga, Olajumoke; Odoh, Samuel_O (April 2021, ChemPhysChem)

   Abstract Copper‐exchanged zeolites are useful for stepwise conversion of methane to methanol at moderate temperatures. This process also generates some over‐oxidation products like CO and CO₂. However, mechanistic pathways for methane over‐oxidation by copper‐oxo active sites in these zeolites have not been previously described. Adequate understanding of methane over‐oxidation is useful for developing systems with higher methanol yields and selectivities. Here, we use density functional theory (DFT) to examine methane over‐oxidation by [Cu₃O₃]²⁺active sites in zeolite mordenite MOR. The methyl group formed after activation of a methane C−H bond can be stabilized at a μ‐oxo atom of the active site. This μ‐(O−CH₃) intermediate can undergo sequential hydrogen atom abstractions till eventual formation of a copper‐monocarbonyl species. Adsorbed formaldehyde, water and formates are also formed during this process. The overall mechanistic path is exothermic, and all intermediate steps are facile at 200 °C. Release of CO from the copper‐monocarbonyl costs only 3.4 kcal/mol. Thus, for high methanol selectivities, the methyl group from the first hydrogen atom abstraction stepmust bestabilizedawayfrom copper‐oxo active sites. Indeed, it must be quickly trapped at an unreactive site (short diffusion lengths) while avoiding copper‐oxo species (large paths between active sites). This stabilization of the methyl group away from the active sites is central to the high methanol selectivities obtained with stepwise methane‐to‐methanol conversion. 

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