Metal‐Organic‐Framework‐Derived Cobalt‐Doped Carbon Material for Electrochemical Ammonia Synthesis under Ambient Conditions

Abstract

Electrocatalytic nitrogen reduction reaction (NRR), as a potential alternative to industrial ammonia synthesis (Haber‐Bosch method), can achieve “green” and sustainable ammonia production under environmental conditions. However, the NRR process is still limited by the slow cleavage of the N≡N triple bond and the existence of a competitive hydrogen evolution reaction. For this reason, many researchers have studied the construction and synthesis of high‐efficiency nitrogen reduction electrocatalysts. Herein, a Co‐based metal‐organic framework (ZIF‐67) was used to prepare Co/C‐900 composites through high‐temperature pyrolysis (900 °C) for ammonia synthesis under environmental conditions. The Co/C‐900 catalysts exhibited excellent NRR performance, with a high NH3 yield of 4.66 μmol cm−2 h−1 at −0.3 V (vs. RHE) and a faradaic efficiency of 11.53 % in 0.1 M potassium hydroxide. This work provides a simple strategy for the design of porous, non‐noble‐metal electrocatalysts for electrochemical NRR.

Metal–Organic Framework Materials for Production and Distribution of Ammonia

“…49−51 Upon annealing at high temperature (400−900 °C) for several hours under N 2 , the cubic ZIF-67(Co) transforms from crystals to porous carbons containing a high content of pyridinic N, pyrrolic N, graphic N, and Co-N x moieties in the structure, which could all benefit or play a role in the adsorption and activation of N 2 . The rate of formation of NH 3 for these Co@N-doped carbons under optimal conditions show dramatic differences of 5.1, 49 19.2, 51 and 80.0 50…”

“…Rather than using pristine MOFs as catalysts, an alternative strategy is to use MOFs as sacrificial templates to generate porous carbon materials. This has been proven to be advantageous in many electrochemical reactions with observed improved conductivity and higher selectivity toward desired products compared with the pristine MOF. , For example, ZIF-67­(Co) has been used as a precursor to fabricate Co@N-doped carbon electrocatalysts for the reduction of N 2 . − Upon annealing at high temperature (400–900 °C) for several hours under N 2 , the cubic ZIF-67­(Co) transforms from crystals to porous carbons containing a high content of pyridinic N, pyrrolic N, graphic N, and Co-N x moieties in the structure, which could all benefit or play a role in the adsorption and activation of N 2 . The rate of formation of NH 3 for these Co@N-doped carbons under optimal conditions show dramatic differences of 5.1, 19.2, and 80.0 μg NH 3 ·h –1 ·mg cat.…”

Two‐Dimensional MXene Supported Bismuth for Efficient Electrocatalytic Nitrogen Reduction

“…Electrocatalytic nitrogen reduction reaction (NRR) is a sustainable method for producing NH 3 under environmental conditions, powered by renewable energy sources and using water and atmospheric nitrogen as sources, and is considered to be an effective alternative to the Haber-Bosch process for N 2 fixation. [12][13] However, the NRR process faces a series of challenges such as poor N 2 adsorption kinetics, inert N�N triple bonds difficult to break, and prone to competitive hydrogen evolution reaction (HER), which leads to generally low NH 3 yield and Faraday efficiency. [14][15][16][17][18] Therefore, the commercial application of electrochemical synthesis of NH 3 is largely restricted.…”

Ru and Fe Alloying on a Two‐Dimensional MXene Support for Enhanced Electrochemical Synthesis of Ammonia

“…[10][11][12][13] Compared with the traditional Haber-Bosch process, the electricity required for the electrochemical synthesis of NH 3 technology can come from renewable resources such as wind, solar and tidal energy, which is green and sustainable. [14][15] Meanwhile, there are many advantages such as moderate reaction conditions, which can be carried out at normal temperature and pressure, low equipment cost, water instead of fossil fuels to provide hydrogen source in the synthesis process, and abundant raw materials, which have attracted widespread attention of researchers in recent years. [16][17][18][19] However, because the N � N bond in N 2 is very stable, it is difficult to be activated under mild conditions, and the NRR process will be accompanied by a strong competitive hydrogen evolution reaction (HER), which severely limits the efficiency of electrochemical NRR to synthesize NH 3 .…”

“…Electrochemical nitrogen reduction reaction (NRR), as an emerging technology to fix N 2 to NH 3 under environmental conditions, is considered to be a very potential replacement technology for the synthesis of NH 3 by the Haber‐Bosch method [10–13] . Compared with the traditional Haber‐Bosch process, the electricity required for the electrochemical synthesis of NH 3 technology can come from renewable resources such as wind, solar and tidal energy, which is green and sustainable [14–15] . Meanwhile, there are many advantages such as moderate reaction conditions, which can be carried out at normal temperature and pressure, low equipment cost, water instead of fossil fuels to provide hydrogen source in the synthesis process, and abundant raw materials, which have attracted widespread attention of researchers in recent years [16–19] .…”