Operando Evolution of the Structure and Oxidation State of Size-Controlled Zn Nanoparticles during CO₂ Electroreduction

Abstract

We explored the size-dependent activity and selectivity of Zn nanoparticles (NPs) for the electrochemical CO reduction reaction (CORR). Zn NPs ranging from 3 to 5 nm showed high activity and selectivity (∼70%) for CO production, whereas those above 5 nm exhibited bulk-like catalytic properties. In addition, a drastic increase in hydrogen production was observed for the Zn NPs below 3 nm, which is associated with the enhanced content of low-coordinated sites on small NPs. The presence of residual cationic Zn species in the catalysts was also revealed during CORR via operando X-ray absorption fine-structure spectroscopy measurements. Such species are expected to play a role in the selectivity trends obtained. Our findings can serve as guidance for the development of highly active and CO-selective Zn-based catalysts for CORR.

Coupled Copper–Zinc Catalysts for Electrochemical Reduction of Carbon Dioxide

“…It is worth noting that Zn(OH) 2 is commonly found on the as-prepared Zn or ZnO surface owing to the exposure to moisture. [25,43] Hence, it is reasonabe to conclude that both Zn(OH) 2 and ZnO coexist on the surface. XRD and TEM analyses confirmed the presence of crystalline ZnO without observation of Zn(OH) 2 , probably owing to the low amount or the amorphous phase of the hydroxide, in agreement with the literature.…”

Heterogeneous Single‐Atom Catalysts for Electrochemical CO2 Reduction Reaction

“…Zinc is a CO‐producing metal for CO 2 RR. Various nanostructured Zn catalysts have been constructed to convert CO 2 to CO, such as porous Zn catalysts, [ 133,134 ] Zn nanoparticles, [ 135 ] Zn nanosheet, [ 136 ] and Zn dendrites. [ 137 ] Similar to its metal/oxide counterparts, single‐atom Zn catalysts have also been reported to convert CO 2 into CO through CO 2 RR.…”

Ultrafine Ag Nanoparticles as Active Catalyst for Electrocatalytic Hydrogen Production

“…Secondly, size reduction many cause intense structural rearrangement on the surface of metallic nanoparticles, leading to a lot of edges, angles and even dynamic metal atoms . As a result, the number of unsaturated coordination atoms increases remarkably, favoring the adsorption of intermediates . Thirdly, as the particle size is reduced to nanoscale, the overlap of d‐orbitals between adjacent metal atoms decreases obviously, leading to the upshift of d‐band center and enhancement of adsorption energy .…”