Atomic Ni Anchored Covalent Triazine Framework as High Efficient Electrocatalyst for Carbon Dioxide Conversion

Abstract

Electrochemically driven carbon dioxide (CO2) conversion is an emerging research field due to the global warming and energy crisis. Carbon monoxide (CO) is one key product during electroreduction of CO2; however, this reduction process suffers from tardy kinetics due to low local concentration of CO2 on a catalyst's surface and low density of active sites. Herein, presented is a combination of experimental and theoretical validation of a Ni porphyrin‐based covalent triazine framework (NiPor‐CTF) with atomically dispersed NiN4 centers as an efficient electrocatalyst for CO2 reduction reaction (CO2RR). The high density and atomically distributed NiN4 centers are confirmed by aberration‐corrected high‐angle annular dark field scanning transmission electron microscopy and extended X‐ray absorption fine structure. As a result, NiPor‐CTF exhibits high selectivity toward CO2RR with a Faradaic efficiency of >90% over the range from −0.6 to −0.9 V for CO conversion and achieves a maximum Faradaic efficiency of 97% at −0.9 V with a high current density of 52.9 mA cm−2, as well as good long‐term stability. Further calculation by the density functional theory method reveals that the kinetic energy barriers decreasing for *CO2 transition to *COOH on NiN4 active sites boosts the performance.

Carbon‐Rich Nonprecious Metal Single Atom Electrocatalysts for CO2 Reduction and Hydrogen Evolution

“…h) CO FEs of Por‐CTF, NiPor‐CTF, and Ni/N‐PC. Reproduced with permission . Copyright 2019, Wiley‐VCH.…”

“…Besides the nanocarbons, CTF, which is N riched in skeleton and porous, has been extensively reported as supports to catch metal atoms with atomic dispersion. For instance, single Ni atoms trapped in triazine nodes (denoted as NiPor‐CTF) were prepared by means of ionothermal strategy, in which the pre‐prepared 5,10,15,20‐tetrakis (4‐cyanophenyl) porphyrin (TPPCN) and Ni(acac) 2 were first mixed to form the NiPor, followed by heating treatment with molten ZnCl 2 at no more than 600 °C to fabricate NiPor‐CTF (Figure g) . Acting as an electrocatalyst for CRR, the NiPor‐CTF with the Ni content of 2.40 wt% reached the maximal CO FE of 97% at −0.9 V (Figure h), which was even higher than Ni/N‐rich porous carbon (denoted as Ni/N‐PC) that is prepared by postpyrolysis of obtained NiPor‐CTF at 900 °C.…”

Tuning the Catalytic Preference of Ruthenium Catalysts for Nitrogen Reduction by Atomic Dispersion

“…Here, a strategy is proposed to adjust the reaction preference of noble metals by tuning the size and local chemical environment of the active sites. [5] In view of these reported works, it is evident that the size of metal particles is a key factor in determining their catalytic performance, and decreasing the size offers an intriguing opportunity to alter the activity and selectivity of these metal catalysts. This model is compared, in terms of the NRR activity, to bulk Ru.…”

“…Since SACs have unique catalytic sites, they usually exhibit a distinct catalytic selectivity as compared to their nanoclusters or nanoparticle counterparts. [5] In view of these reported works, it is evident that the size of metal particles is a key factor in determining their catalytic performance, and decreasing the size offers an intriguing opportunity to alter the activity and selectivity of these metal catalysts. [3] Isolated Co single-site catalysts anchored on a N-doped porous carbon nanobelt exhibits an excellent catalytic performance for oxidation of ethylbenzene with 98% conversion and 99% selectivity, whereas the Co nanoparticles are essentially inert.…”

Template‐free synthesis of novel hollow carbon nanospheres with dual active sites as catalyst for fuel cell cathode to improve oxygen reduction reaction performances

“…Pore size distribution and specific surface area are listed in Table 1. The N1s peaks of the HCN-FNFCG-650 at 398.5, 399.7, 401.1, and 402.1 eV are pointed to pyridinic N, pyrrolic N, graphitic N, and oxidized N. 46 As for the N1s peak at 404.2 eV, it may be metallic N. In previous researches, the Fe atoms can bind with graphitic N and pyridinic N to produce the ORR active sites. Mean pore diameter of HCN-FNFCG-650 is 12.766 nm, higher than those of other HCN-FNFCG samples in Figure 4C and D. The micro-and meso-pores coexisted in all samples.…”