Efficient Electrocatalytic Reduction of CO₂to Ethane over Nitrogen-Doped Fe₂O₃

Abstract

Non-copper catalysts are seldom reported to generate C2+ products, and the e cient over these catalysts were low. In this work, we reported an iron-based catalyst centered in nitrogen doped γ-Fe2O3 (xFe2O3-N), which yielded C2H6 as major product in H-cell. At -2.0 V vs Ag/Ag+, the Faradaic e ciency (FE) for ethane reaches 42% with current densities of 32 mA cm−2. This is the rst report about selective CO2 reduction to ethane (C2H6) over iron-based catalyst. Results showed that catalyst possessing FeO1.5-nNn sites enriched with oxygen vacancies was bene cial for the stabilization of *COOH intermediate. The exposure of two adjacent surfaces of Fe atoms was conducive to lower the energy barrier for C−C coupling over FeO1.5-nNn sites, facilitating the generation of C2H6. This work provides a strategy for design of novel iron-based catalyst with tunable local coordination and electronic structures for converting CO2 into C2 products in CO2RR. Full TextElectrocatalytic reduction of CO 2 under ambient conditions using renewable energy has emerged as an attractive way to maintain carbon balance, which is regarded as one of the cleanest and e cient approaches 1-3 . Recently, numerous electrocatalysts have been developed for CO 2 reduction reaction (CO 2 RR) 4-7 . However, the majority of these catalyst systems have low e cient for multicarbon (C 2+ ) products due to the multiple pathways involved in the reaction process 8 . Cu-based catalysts are mostly reported to convert CO 2 into C 2+ products such as ethylene, alcohols and acetic acid [9][10][11] . Up to now, noncopper catalysts are rarely reported to generate C 2+ products 12,13 .

Multifunctional Au/Hydroxide Interface toward Enhanced C–C Coupling for Solar-Driven CO2 Reduction into C2H6

“…Notably, the CH 4 product by CO 2 photoreduction was formed by the *CH 3 hydrogenation, , and hence the C 2 H 6 generation was kinetically faster with the direct C–C coupling of *CH 3 during the reaction. Comprehensibly, depending on whether the C 1 species of *CO or the possible *CHO was the underlying factor for the C–C coupling step, the *CH 2 CH 2 species or the C 2 H 4 product could be generated during the reaction. , However, the C 2 H 4 product was undetected in the above tests, predicting that the *CH 2 CH 2 intermediate was uneasily obtained with the formation of the C 2 H 6 product. Additionally, only a trace of C 2 H 6 (Figure c) was detected on using the C 2 H 4 reaction gas (∼253 ppm, C 2 H 4 + Ar), suggesting a difficult reaction via the *CH 2 CH 2 pathway for the C 2 H 6 formation.…”

Electrocatalytic Reduction of Carbon Dioxide to High-Value Multicarbon Products with Metal–Organic Frameworks and Their Derived Materials

“…Though the Cu-based electrocatalysts have emerged as promising candidates to boost C 2+ production in CO 2 RR, some noncopper electrocatalysts have also achieved superior selectivity for C 2+ product generation. Very recent investigations indicated that the hexagonal cobalt nanosheets possess excellent selectivity toward ethanal production with FE of 60% at −0.4 V (vs RHE), while the nitrogen-doped γ-Fe 2 O 3 favors the formation of ethane with FE of 42% at −2.0 V (vs Ag/Ag + ) . Inspired by this point, it could be feasible to prepare noncopper MOFs (e.g., cobalt- and iron-based MOFs), as well as their derived materials, as electrocatalysts in boosting the conversion of CO 2 to C 2+ products.…”

“…Very recent investigations indicated that the hexagonal cobalt nanosheets possess excellent selectivity toward ethanal production with FE of 60% at −0.4 V (vs RHE), 245 while the nitrogen-doped γ-Fe 2 O 3 favors the formation of ethane with FE of 42% at −2.0 V (vs Ag/Ag + ). 246 Inspired by this point, it could be feasible to prepare noncopper MOFs (e.g., cobalt-and iron-based MOFs), as well as their derived materials, as electrocatalysts in boosting the conversion of CO 2 to C 2+ products. Sixth, apart from MOFs, other similar porous materials, such as COFs and HOFs, also hold great potential of promoting C 2+ production in electrochemical CO 2 RR, although most of the reported COFs and HOFs tend to facilitate the CO or CH 4 production at current stage.…”

A rational design of functional porous frameworks for electrocatalytic CO2reduction reaction

“…For instance, an N-doped γ -Fe 2 O 3 core-shell architecture was reported to possess a C 2 H 6 FE of 42% with a current density of 32 mA cm −2 . 27 A FeP nanoarray exhibited a CH 3 CH 2 OH FE of 14.1% and current density of 2 mA cm −2 . 28 A Fe 2 P 2 S 6 nanosheet was also reported with a CH 3 CH 2 OH FE of 23.1% and current density of 0.5 mA cm −2 .…”

“…, Cu, Co, Ni, Fe, and Zn), metals with CO selectivity (including Sc, Mn, Y, and Re), and metals with HCOOH selectivity (such as In, Sn, and Bi). 23–30 Among them, the Cu element has been demonstrated to exhibit the greatest potential for the ECO 2 RR, which is capable of generating a series of hydrocarbons, e.g. , HCOOH, CH 4 , CH 3 OH, C 2 H 4 , and CH 3 CH 2 OH.…”