N and OH-Immobilized Cu₃ Clusters In Situ Reconstructed from Single-Metal Sites for Efficient CO₂ Electromethanation in Bicontinuous Mesochannels

Abstract

Cu-based catalysts hold promise for electrifying CO 2 to produce methane, an extensively used fuel. However, the activity and selectivity remain insufficient due to the lack of catalyst design principles to steer complex CO 2 reduction pathways. Herein, we develop a concept to design carbon-supported Cu catalysts by regulating Cu active sites' atomic-scale structures and engineering the carbon support's mesoscale architecture. This aims to provide a favorable local reaction microenvironment for a selective CO 2 reduction pathway to methane. In situ X-ray absorption and Raman spectroscopy analyses reveal the dynamic reconstruction of nitrogen and hydroxyl-immobilized Cu 3 (N,OH-Cu 3 ) clusters derived from atomically dispersed Cu−N 3 sites under realistic CO 2 reduction conditions. The N,OH-Cu 3 sites possess moderate *CO adsorption affinity and a low barrier for *CO hydrogenation, enabling intrinsically selective CO 2 -to-CH 4 reduction compared to the C−C coupling with a high energy barrier. Importantly, a block copolymer-derived carbon fiber support with interconnected mesopores is constructed. The unique long-range mesochannels offer an H 2 O-deficient microenvironment and prolong the transport path for the CO intermediate, which could suppress the hydrogen evolution reaction and favor deep CO 2 reduction toward methane formation. Thus, the newly developed catalyst consisting of in situ constructed N,OH-Cu 3 active sites embedded into bicontinuous carbon mesochannels achieved an unprecedented Faradaic efficiency of 74.2% for the CO 2 reduction to methane at an industry-level current density of 300 mA cm −2 . This work explores effective concepts for steering desirable reaction pathways in complex interfacial catalytic systems via modulating active site structures at the atomic level and engineering pore architectures of supports on the mesoscale to create favorable microenvironments.

A novel thiophene-linked metalloporphyrin conjugated polymer: a highly efficient trifunctional electrocatalyst for overall water splitting and oxygen reduction

“…It should be noted that the stability of SACs under applied potentials may be affected. 47,48 To indicate the stability of Co–N 4 /TP under working conditions, a combination of constant potential method, implicit solvent and molecular dynamics is employed to investigate the stability of Co SAC. As displayed in Fig.…”

Engineering Spatially Adjacent Redox Sites with Synergistic Spin Polarization Effect to Boost Photocatalytic CO2 Methanation

“…Photocatalytic technology-assisted CO 2 resource utilization emerges as a viable strategy to advance the carbon-neutral cycle and facilitate the transition of societal energy systems from fossil fuels by harnessing hydrocarbon compounds for energy storage. − In contrast to the commonly produced CO, the generation CH 4 is preferable due to its extensive applications as chemical feedstocks and fuel additives. , Nonetheless, the efficiency of photocatalytic CO 2 to CH 4 conversion is constrained by the sluggish kinetics of the proton-coupled electron transfer process despite its thermodynamic favorability . This limitation is exacerbated by the necessity for concurrent oxidation half-reactions involving hole migration, which occurs at a significantly slower rate compared to electron transfer by two to three orders of magnitude. , Such kinetic disparities, particularly the slower kinetics of H 2 O oxidation, result in hole accumulation, fostering photogenerated charge recombination and thereby detracting from the efficiency of CO 2 photoreduction. , Additionally, the activation of CO 2 molecules predominantly requires proton assistance due to the high energy barrier ( E = −1.9 V vs NHE) for direct reduction of CO 2 to *CO 2 – .…”

Not One, Not Two, But at Least Three: Activity Origin of Copper Single-Atom Catalysts toward CO2/CO Electroreduction to C2+ Products

“…Single-atom catalysts (SACs) featuring well-defined single-atom active sites have become an excellent platform for CO 2 RR. − The SACs can efficiently activate CO 2 molecules owing to their unique electronic and structural properties, achieving a Faradaic efficiency (FE) of over 95% for CO despite the variety of metal centers (except Cu). − The successes of the SACs and metallic Cu catalysts have promoted the realization of Cu SACs for generating C 2+ products, while the C 2+ activity origin of many Cu SACs was identified as the structural change from single-atom Cu (Cu 1 ) (leaching from the substrate) to Cu clusters/nanoparticles during operation. − …”

“…As mentioned before, Cu 1 atoms in Cu SACs often undergo leaching and aggregation processes during reaction to form Cu clusters/nanoparticles. − To this end, we evaluated the structural stability of the Cu 1 atoms of Cu 1 @C 3 N 4 through AIMD simulations with a slow-growth approach (Figure a,b). The Cu 1 atom can easily migrate from the original position to its adjacent equivalent position ( E a ≈ 0.28 eV).…”