Activity Origin of Antimony Nanosheets toward Selective Electroreduction of CO₂ to Formic Acid

Abstract

Main-group metal antimony (Sb) holds great promise for facilitating the electroreduction of CO2 to formic acid (HCOOH), but the underlying mechanism remains unclear. Herein, by means of density functional theory computations and microkinetic modeling, we investigate CO2 reduction on Sb while considering the exposed facets and layer thickness. Our calculations indicate that the typical facets of Sb, especially the dominating (001) basal plane, adsorb the key intermediate of the HCOOH pathway (i.e., *OCHO) favorably compared with the other competing intermediates *COOH and *H, which rationalizes existing experimental observations. Nontrivial thickness-dependent activity induced by the quantum confinement effect is observed on the Sb (001) nanosheets, whose layer number ranges from one to six. Among these Sb nanosheets, the bilayer exhibits the highest activity, while, unexpectedly, the monolayer is almost inert. Additionally, the catalytic performance of the bilayer can be greatly enhanced through strain engineering. This work reveals the activity origin of Sb for the conversion of CO2 to HCOOH and provides strategies for the improvement of main-group metal catalysts.

Enhancing Electrocatalytic Nitrogen Reduction on Few-Layer Antimonene in an Aqueous Potassium Sulfate Electrolyte

“…The exfoliation of antimony crystals is further confirmed by transmission electron microscopy (TEM). As shown in Figure b, the obtained few-layer antimonene displays a polygonal nanosheet morphology, implying the exposure of rich-edge active sites . In the high-resolution TEM (HRTEM) image, the lattice fringes with a distance of 0.31 nm can be assigned to the (012) facet of rhombohedral antimony (Figure c).…”

“…As shown in Figure 5b, the obtained few-layer antimonene displays a polygonal nanosheet morphology, implying the exposure of rich-edge active sites. 29 In the high-resolution TEM (HRTEM) image, the lattice fringes with a distance of 0.31 nm can be assigned to the (012) facet of rhombohedral antimony (Figure 5c). Atomic force microscopy (AFM, Figure 5d) imaging of few-layer antimonene further confirms the nanosheet morphology with an average thickness of 4.4 nm.…”

“…Nanostructured group-VA elemental materials such as black phosphorus nanosheets and bismuth nanocrystals , own similar valence electrons with N to render strong p orbital hybridization and have limited electron accessibility to suppress the HER. Particularly, antimonene with considerable stability, high carrier mobility, and superior spintronic properties is a promising two-dimensional layered catalyst . While antimonene is recently demonstrated to catalyze the NRR with considerable activity, the electronic structures of active N 2 -adsorption sites and the mechanism of NRR on different edge surfaces remain not fully understood.…”

“…Particularly, antimonene with considerable stability, 26 high carrier mobility, 27 and superior spintronic properties 28 is a promising two-dimensional layered catalyst. 29 While antimonene is recently demonstrated to catalyze the NRR with considerable activity, the electronic structures of active N 2 -adsorption sites and the mechanism of NRR on different edge surfaces remain not fully understood. Moreover, the hydrated alkali cations anchored by *OH on the electrode surface in alkaline media would promote the electron transfer between adsorbed species and hydrated cations through noncovalent bonding.…”

Extensively amino-functionalized graphene captures carbon dioxide

“…The different means of CO 2 chemical fixation, separation, and conversion to improve its storage are being currently developed. 27,[35][36][37][38][39][40][41][42][43] The synthesis of valuable reactants out of abundant CO 2 instead of its geological storage represents a perspective and seemingly quite successful direction of research in synthetic chemistry. The latter greatly benefits from the explosive development of novel fascinating catalysis schemes.…”