Electrocatalytic synthesis of ammonia at ambient conditions from water and nitrogen using zinc oxide electrocatalyst

• Main Author: Lee, Carmen
• Other Authors: Alex Yan Qingyu
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Materials
• Online Access: http://hdl.handle.net/10356/77538
• Institution: Nanyang Technological University

The second most produced chemical globally is Ammonia (NH3). The current industrial way to manufacture ammonia is energy intensive which contribute to environmental pollution significantly. [1] To meet the demand for ammonia, we need to come up with sustainable and “green” production methods that use lesser resources. Electrochemical nitrogen fixation is a potential alternative method for the Haber-Bosch process for ammonia production. [2] However, the progress of the current electrochemical nitrogen fixation (NRR) is hindered by strong rivalry from the side reaction, hydrogen evolution reaction (HER), for many NRR catalysts. Thus, both the rate of formation of ammonia and the faradaic efficiency are very low. [3] This project focuses on synthesizing Zinc Oxide (ZnO) as an electro-catalyst used to synthesise ammonia via electrochemical method. Zinc oxide was produced using hydrothermal synthesis followed by heat treatment. The obtained ZnO sample was characterized by SEM, XRD and voltammetry analysis. In the electrochemical test conducted, the ZnO nanosheets were able to enable adsorption of both hydrogen and nitrogen. This electrocatalyst achieved an ammonia yield of 7.52 µg h–1 mg–1 with a Faradaic Efficiency of 0.56 % at -0.1 V in 0.1 M Na2SO4. It is observed that ZnO has comparable NRR performance as compared to many of the electrocatalysts that has been reported thus far. Therefore, we envisage this as a starting point for the development of high-performance electrocatalyst that can be used for the electrochemical method of producing ammonia to address the global demand of ammonia across industries.