p-Block Indium Single-Atom Catalyst with Low-Coordinated In–N Motif for Enhanced Electrochemical CO₂ Reduction

Abstract

Electrochemical CO2 reduction represents a promising path toward the production of value-added chemicals. Atomically dispersed metal sites on nitrogen-doped carbon have demonstrated outstanding catalytic performance in this reaction. However, challenges remain in developing such catalysts beyond transition metals. Herein, we present two types of p-block indium single-atom catalysts: one with four nitrogen coordinated (In–N4) and another with three nitrogen coordinated with one vacancy nearby (In–N3–V). In electrochemical CO2 reduction, the In–N3–V site can achieve maximum CO Faradic efficiency (FECO) of 95% at −0.57 V vs reversible hydrogen electrode (RHE) in an aqueous medium. This outperforms the intact In–N4 catalyst with the maximum FECO of 80% at −0.47 V vs RHE. Density functional theory calculations on the mechanism suggest that structural change from In–N4 to In–N3–V brings the In orbital (s and p z ) energies closer to the Fermi energy. These hybridized orbitals are responsible for lowering the energy barrier for COOH* intermediate formation, thus enhancing the catalytic performance. This work sheds light on the relationship between catalytic performance and structure of In single-atom sites, highlighting the importance of tailoring the electron state of s and p z orbitals in developing efficient p-block single-atom catalysts for electrochemical CO2 reduction.

p-Block Antimony Single-Atom Catalysts for Nitric Oxide Electroreduction to Ammonia

“…Single-atom strategy offers a promising opportunity to maximize the catalytic performance of p-block metals, owing to the maximized atom-utilization efficiency in single-atom catalysts (SACs). − Albeit p-block metal SACs have not been reported for the NORR, their applications in other important electrocatalytic reactions deliver the superior catalytic ability to achieve both high activity and selectivity. − Furthermore, amorphous materials naturally possess abundant surface defects which provide large amounts of anchoring sites to strongly immobilize single metal atoms with high loading. − Therefore, the catalysts based on p-block metal single atoms immobilized on amorphous substrates are expected to exhibit the fascinating catalytic performance for highly active and selective NORR.…”

A rational design of functional porous frameworks for electrocatalytic CO2reduction reaction

“…, Sc, 60 Mn, 61 Y, 60 Zr, 50,223,226 and Re 62 ) and main group ( e.g. , Al, 49,227 In, 40,63,66,67,69,70 Sn, 41,64 and Bi 41,42,65,68,228–231 ) metals, as shown in Fig. 2.…”

“…In addition to the above-mentioned intact In–N 4 sites, Daasbjerg further adopted the regulation of local coordination environment on the active site configuration to obtain In–N 3 V (V: vacancy) sites. 70 In terms of the electron state tailoring in the active sites, it was unveiled via DFT calculations that structural change from In–N 4 to In–N 3 V let the In orbital (s and p z ) energies closer to the Fermi energy ( E f ), thus lowering the formation energy of *OCHO, indicating the feasibility of configuration optimization of In active sites to achieve improved ECO 2 RR activity, as displayed in Fig. 28h and i.…”

“…41,68 A reasonable explanation is that strong hybridization exists between the 4d orbital of the In, Sn, and Bi atoms and the 2p orbital of the O in the *OCHO intermediates, leading to an enhanced binding effect in the *OCHO intermediate and favourable HCOOH production. 69,70…”

Enhanced stability of sub-nanometric iridium decorated graphitic carbon nitride for H2 production upon hydrous hydrazine decomposition

“…13,14 Carbon materials are highly attractive as catalyst supports, because of their relatively low costs and high tunability of the physicochemical properties. Indeed, chemical modification of a carbon surface can improve the stabilization of few-atom clusters and single atoms, [15][16][17][18][19][20] and strongly influence the nature of the metal species, in a way which resembles organic ligands in organometallic catalysis, thus opening up the opportunity to realize high site specificity. [20][21][22][23] The presence of heteroatoms (e.g.…”