Template-Sacrificing Synthesis of Well-Defined Asymmetrically Coordinated Single-Atom Catalysts for Highly Efficient CO₂ Electrocatalytic Reduction

Abstract

Although various single-atom catalysts have been designed, atomically engineering their coordination environment remains a great challenge. Herein, a one-pot template-sacrificing pyrolysis approach is developed to synthesize well-defined Ni−N 4 −O catalytic sites on highly porous graphitic carbon for electrocatalytic CO 2 reduction to CO with high Faradaic efficiency (maximum of 97.2%) in a wide potential window (−0.56 to −1.06 V vs RHE) and with high stability. In-depth experimental and theoretical studies reveal that the axial Ni−O coordination introduces asymmetry to the catalytic center, leading to lower Gibbs free energy for the rate-limiting step, strengthened binding with *COOH, and a weaker association with *CO. The present results demonstrate the successful atomic-level coordination environment engineering of high-surface-area porous graphitic carbon-supported Ni single-atom catalysts (SACs), and the demonstrated method can be applied to synthesize an array of SACs (metal−N 4 −O) for various catalysis applications.

Rational design, application and dynamic evolution of Cu–N–C single-atom catalysts

“…[96][97][98][99] As a simple and reproducible synthesis strategy, the template-sacricing strategy is suitable for the synthesis of carrier materials with a high specic surface area. [100][101][102][103][104][105] Dopamine, known for its excellent adhesion and high carbonization yield, is a competitive candidate for the synthesis of nitrogen-doped carbon. 106 However, in the synthesis of catalysts, dopamine oen shows a wide pore size distribution and low specic surface area, which limit its application.…”

A mesh-like BiOBr/Bi2S3 nanoarray heterojunction with hierarchical pores and oxygen vacancies for broadband CO2 photoreduction

“…6e reveals the free energy diagrams with four successive elementary reaction steps involved: adsorption of CO 2 (* + CO 2 → *CO 2 ), proton-coupled electron transfer to form the *COOH intermediate (*CO 2 + H + + e − → *COOH), further hydrogenation of *COOH to form *CO (*COOH + H + + e − → *CO + H 2 O), and *CO desorption to produce CO (*CO → * + CO). 63,64 The process at the vacancy sites of V O -BiOBr(010) is illustrated in Fig. 6f.…”

Research progress of asymmetrically coordinated single-atom catalysts for electrocatalytic reactions

“…Among them, the two-dimensional spatial resolution of HADDF-STEM images can reach below 1 Å, and single atoms can be clearly distinguished. 37,[42][43][44][45] XAFS can be used to measure the structure of X-ray absorption coefficients as a function of energy. Particularly, extended X-ray absorption ne structure (EXAFS) can be used to demarcate the species of atoms in materials and give adjacent atomic structures, which is a powerful tool for characterizing asymmetric coordination structures.…”