Orbital coupling of hetero-diatomic nickel-iron site for bifunctional electrocatalysis of CO2 reduction and oxygen evolution

Abstract

While inheriting the exceptional merits of single atom catalysts, diatomic site catalysts (DASCs) utilize two adjacent atomic metal species for their complementary functionalities and synergistic actions. Herein, a DASC consisting of nickel-iron hetero-diatomic pairs anchored on nitrogen-doped graphene is synthesized. It exhibits extraordinary electrocatalytic activities and stability for both CO2 reduction reaction (CO2RR) and oxygen evolution reaction (OER). Furthermore, the rechargeable Zn-CO2 battery equipped with such bifunctional catalyst shows high Faradaic efficiency and outstanding rechargeability. The in-depth experimental and theoretical analyses reveal the orbital coupling between the catalytic iron center and the adjacent nickel atom, which leads to alteration in orbital energy level, unique electronic states, higher oxidation state of iron, and weakened binding strength to the reaction intermediates, thus boosted CO2RR and OER performance. This work provides critical insights to rational design, working mechanism, and application of hetero-DASCs.

Three-dimensional porphyrinic covalent organic frameworks for highly efficient electroreduction of carbon dioxide

“…3,4 Compared with other catalytic conversion methods, the CO 2 electroreduction reaction (CO 2 RR) using renewable energy resources for electricity can convert CO 2 to various value-added chemicals under mild and clean conditions. 5–11 Compared with other products, the two-electron involved product CO that has been widely used to produce synthetic liquid fuels by the Fischer–Tropsch process may be more easily produced via the CO 2 RR. 12–15 However, the sluggish kinetics of the CO 2 RR and the associated hydrogen evolution reaction (HER) usually lead to low current density and selectivity, 16,17 which makes it difficult to meet the requirement of commercial applications.…”

Size-controlled, hollow and hierarchically porous Co2Ni2 alloy nanocubes for efficient oxygen reduction in microbial fuel cells

“…6b exhibited dominant broad peaks of Ni 2p 1/2 (870.0 eV) and Ni 2p 3/2 (850.3 eV), which could be deconvoluted into subpeaks of Ni 0 (870.0 and 852.6 eV), Ni 2+ (872.6 and 854.5 eV), and satellite Ni (875.7 and 858.6 eV). 63,64 The obvious binding energy shifts of the Ni 2p 3/2 subpeaks in the Co 3 Ni 1 , Co 2 Ni 2 and Co 1 Ni 3 HANCs were 1.9, 1.5, and 0.8 eV, respectively (Table S7†). The results obtained from the XPS analyses also confirmed the formation of binary Co–Ni sites in the Co x Ni y HANCs.…”

Functional Aqueous Zinc–Acetylene Batteries for Electricity Generation and Electrochemical Acetylene Reduction to Ethylene

“…in Figure 1b and S10. Significantly, a peak power density of 2.22 mW cm À 2 was obtained at a current density of 12.6 mA cm À 2 , which unprecedentedly exceeded those for state-of-the-art Zn-CO 2 batteries such as 1.05 mW cm À 2 for N atoms and coordinatively unsaturated Ni-N 3 moieties coanchored carbon nanofibers (Ni-N 3 -NCNFs), [30] 1.24 mW cm À 2 for a surface-lithium-doped tin catalyst (s-SnLi), [27] 1.36 mW cm À 2 for a diatomic NiFe catalyst supported by nitrogen-doped graphene (NiFe-DASC), [28] and 1.8 mW cm À 2 for atomically dispersed monovalent zinc anchored on nitrogenated carbon nanosheets (Zn/NC NSs). [29] Markedly, the Zn-C 2 H 2 battery generated a stable open circuit potential of 1.14 V (Figure 1c), which was much larger than those for currently reported Zn-CO 2 batteries, for example 0.6 V for s-SnLi, [27] 0.79 V for cedar biomassderived N-doped graphitized carbon (CB-NGC-2), [33] and 0.82 V for carbon nanotubes directly grown on copper mesh (CNTs@Cu).…”