Carbon black supported manganese phthalocyanine: Efficient electrocatalyst for nitrogen reduction to ammonia

Abstract

Abstract Ammonia (NH3) is regarded as a renewable energy source as well as an important molecule for agricultural applications. The energy‐intensive Haber‐Bosch method produces large amounts of CO2 gas during ammonia production. As an alternative, there has recently been much interest in the electrocatalytic production of NH3 via the electrochemical nitrogen reduction reaction (ENRR) process utilizing renewable energy under ambient condition. Herein, we report a conducting carbon–supported manganese phthalocyanine electrocatalyst as an efficient electrocatalyst for ENRR applications. The MnPc electrocatalyst exhibited the activity with an ammonia production rate of 61.8 μg h−1mg−1cat with Faradaic efficiency (FE) of 31.3% @–0.4 V vs. RHE, respectively, under ambient condition in 0.1 M HCl solution whereas MnPc/C electrocatalyst exhibited an enhanced the productivity with an ammonia yield rate of 127.7 μg h−1mg−1cat with FE of 35.3% @–0.4 V vs. RHE, respectively. The reliability of N origin in ammonia formation is demonstrated by 1H‐NMR experiments and multiple control analysis. These results open the way for the further study of carbon‐supported transition‐metal phthalocyanine compounds for electrochemical nitrogen fixation to NH3.

Keywords

• ammonia synthesis
• ENRR
• Haber‐Bosch process
• metal phthalocyanine
• nitrogen fixation