Bimetallic effects on Zn-Cu electrocatalysts enhance activity and selectivity for the conversion of CO2 to CO

Guiding the Catalytic Properties of Copper for Electrochemical CO2 Reduction by Metal Atom Decoration

“…The Sn/Cu films are a notable outlier, as they show a relatively high selectivity for CO 2 R to CO and the only suppression in activity for the HER in comparison to that of pure Cu. While the reaction mechanism must be further investigated on Sn/Cu films to understand the origin of these trends, on the basis of the current evidence, we hypothesize that the formation of a Cu–Sn intermetallic compound and/or Cu–Sn–O complex oxide leads to an active site distribution that is quite different when compared to that of pure Cu and other M/Cu films. , Future operando synchrotron X-ray scattering and spectroscopy experiments on Cu bimetallics will aid in understanding the surface structure under reaction conditions, enabling better correlations to physics-based models and improving structure–reactivity relationships beyond what we have established in the current work.…”

“…Also, Sn greatly enhances CO formation, especially at higher overpotentials; the other metals investigated in this work do not show the same promotion effect for CO formation. The enhancement of CO formation over the Sn/Cu film might result from the weakened binding strengths of C-tethering intermediates such as CO*, CHO*, and COH* to the film for the greater than 2e – pathways and the possible bimetallic effect between Cu and an oxophilic metal to stabilize the COOH* intermediate that results in CO, compared to the Cu(100) standard. − ,, All of the M atoms except for In and Sn promote the competing HER pathway (Figure f), although the extent of promotion seems to depend on the identity of the M atoms. Namely, Mo enhances the HER at all of the potentials studied in this work, Ni does this at a higher overpotential, and noble metals (i.e., Au, Ag, and Pd) do this at a lower overpotential.…”

“…Currently, it is well-known that copper (Cu) is the only metal that can electrochemically produce a wide range of hydrocarbons and oxygenates by transferring more than two electrons into CO 2 . ,− At present, one of the key challenges is to improve the product selectivity for an electrochemical CO 2 reduction (CO 2 R) over Cu-based catalysts. , Thus far, Cu-based bimetallics have been intensively investigated to tune the product distribution of CO 2 R over Cu, − using secondary elements ranging from noble metals (Ag, − Au, − and Pd − ) to base metals (In, − Sn, − and Zn , ). While these works have yielded many useful insights on tuning bimetallic effects for CO 2 R, diverse electrocatalytic behaviors have been observed even for the same Cu bimetallics, since electrodes are prepared with a broad range of different surface structures and morphologies, and some are examined under different reaction conditions .…”

Metal Oxides as Catalyst/Supporter for CO2 Capture and Conversion, Review

“…On the other hand, a two-metal, Zn-Cu electric catalyst introduced selectivity and high-efficiency activity to convert CO 2 to CO, where DFT calculations demonstrated that the fusion of copper on the zinc surface reduced the activation capacity from 0.44 to 0.15 volts, increasing the selectivity of Zn-Cu to be 97% faradaic efficiency. In contrast, zinc selectivity was only 30% faradaic efficiency, indicating that incorporating copper into zinc generates a synergistic effect that improves the conversion of CO 2 [88]. The highly cooperative win-win metal-oxide interaction that enables unprecedented catalytic functionalities for electrochemical CO 2 reduction reactions has been investigated in a single SnOx/Ag catalyst.…”

Elucidating the structure-dependent selectivity of CuZn towards methane and ethanol in CO2 electroreduction using tailored Cu/ZnO precatalysts

“…On the other side, the conclusions of previous studies on its catalytic behaviour are controversial. [9][10][11][12][13][14][15] While high selectivity for ethanol was found in certain cases, preferential methane production was also reported, as well as selectivity towards CO. [9][10][11][12][13][14][15] Composition certainly plays an important role in directing selectivity, with higher Zn content generally favouring CO; 13,16 yet other factors must come into play to justify the observed selectivity patterns towards methane or ethanol in similar compositional ranges. [9][10][11][12][13][14][15] For example, CuZn nanostructured catalysts were shown to facilitate the formation of ethanol at a Zn content between 10% and 30%.…”