Electrochemical nitrogen reduction to ammonia using mesoporous iron oxide with abundant oxygen vacancies

Abstract

The electrochemical nitrogen reduction reaction (NRR) has emerged as an environmentally benign and sustainable approach for ammonia (NH3) synthesis. For the development of an efficient NRR electrocatalyst, herein, mesoporous hematite...

Cu-Doped Fe2O3 Nanorods for Enhanced Electrocatalytic Nitrogen Fixation to Ammonia

“…–1 and 16.4%, respectively. This optimum performance of Cu–Fe 2 O 3 -1 is comparable to or even exceeds those of recently reported Fe oxide-based electrocatalysts, ,− ,− ,− and the marked FE is higher than that of Zn-doped Fe 2 O 3 , as expected in the Introduction. Upon shifting the applied potential in a negative direction beyond −0.20 V, both NH 3 formation rate and FE gradually decreased because of the competing HER process (Figure S14), whereas the smaller FE observed at −0.10 V is likely due to uncontrollable experimental error and the capacitance of the carbon support. , The durability of Cu–Fe 2 O 3 -1 was evaluated by conducting a consecutive cycling test and a long-term chronoamperometry measurement.…”

“…Furthermore, our group developed O V -enriched mesoporous Fe 2 O 3 and revealed that O V s promote N 2 activation (15.3 μg h –1 mg cat. –1 , 13.2%) from both experimental and computational results …”

“…−1 , 13.2%) from both experimental and computational results. 42 In this study, we studied the electrochemical NRR using Fe 2 O 3 nanorods (NRs) doped with Cu. Since the introduction of low-valence elements generally creates O V s on metal oxides as compensation for charge imbalance, heteroatom doping is considered to be effective to develop active NRR catalysts.…”

“…Furthermore, in addition to the exploration of novel catalyst compounds, − various approaches such as morphological control, − integration with other materials, , and optimization of reaction conditions , have also been investigated to improve catalytic performance. Among these, engineering oxygen vacancies (O V s) on the catalyst surface has been demonstrated to be highly effective to enhance the NRR activity by strengthening N 2 adsorption, − and some research groups reported Fe oxide NRR catalysts with abundant O V s. − For example, Cui et al introduced O V s to hematite (Fe 2 O 3 ) nanopowder by annealing under specific conditions and showed improvement of the NH 3 formation rate (1.45 μg h –1 cm –2 ) and Faradaic efficiency (FE, 8.28%) by increasing O V concentration . Zhang et al reported good NRR performance (32.1 μg h –1 mg cat.…”

Recent Developments of Dual Single‐Atom Catalysts for Nitrogen Reduction Reaction

“…Up to now, a series of characterization methods have been used for quantitative characterizations for NH 3 yield, such as the colorimetric method (indophenol blue method, [9,19,84] the phenate method, [85] and Nessler's reagent method [86] ), 1 H nuclear magnetic resonance (NMR), [9] ammonia-ion selective electrode (ASE) method, [15] and ion chromatography (IC), [15] and so on.…”