Bismuth based coordination polymer derived composite for electrochemical nitrogen reduction reaction Deep Lata Singh , Vineet Mishra, G. Ranga Rao Indian Institute of Technology Madras, India Global demand of ammonia and harsh condition of temperature and pressure used in Haber-Bosch process makes the N 2 reduction to ammonia via electrochemical method a promising commercial approach. Electrochemical conversion of N 2 to ammonia is an eco-friendly method which needs less energy to operate the reduction process with less emission of CO 2 . 1 The catalysts designed using transition metals usually have parallel competing HER and thus reducing the efficiency of the catalyst towards N 2 reduction. This occurs due to the pronounced affinity of the transition metals to the H-atom. 2 Keeping these conditions in mind we have designed a catalyst using a main group element which also supresses the HER. Bismuth has affinity to adsorb N 2 by involving its 6p orbital. The strong interaction between 6p orbital of Bi and 2p orbital of N atom enhances the N 2 activation. 3,4 Furthermore, providing carbon support elevates the exposed active surface area of the catalyst concurrently increasing the conductivity, but addition of carbon support while preparation of working electrode can block the active sites. Therefore, direct synthesis of carbon supported catalyst can not only improve the catalytic activity but reduces the chances of blocking of active sites. 5 Active carbidic carbon is also known to adsorb nitrogen molecules and atoms facilitating the ammonia formation. 6 In this work, Bi nanoparticles supported on carbon (BiNP@C) is directly synthesized by calcination of Bi based coordination polymer. BiNP@C is used to reduce N 2 to ammonia electrochemically. The synthesized material is characterized by PXRD, IR, UV, TGA and HR-SEM methods. The electrochemical studies on this material are performed by linear sweep voltammetry (LSV), cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) in H-cell containing two compartments separated by a nafion membrane. The product is analysed by indophenol blue method and maximum absorbance peak is observed at 655 nm. The results obtained in this work give valuable insights into the cogent design of the catalyst to improve catalytic performance towards electrochemical N 2 reduction to ammonia. References 3. Yao, C. Tang, L. Li, B. Xia, A. Vasileff, H. Jin, Y. Zhang and S.-Z. Qiao, Adv. Energy Mater . 2020, 10 , 2001289. 4. Chanda, R. Xing, T. Xu, Q. Liu, Y. Luo, S. Liu, R. A. Tufa, T. H. Dolla, T. M. and X. Sun, Chem. Commun., 2021, 57 , 7335- 7349. 5. Gu, W. Chen and X. Li, J. Mater. Chem. A , 2022, 10 , 22331-22353. Ranga Rao and C. N. R. Rao, Appl. Surf. Sci. , 1990, 45 , 65-69. 1. Zhou, B. Xiong, L. Chen and J. Shi, J. Mater. Chem. A , 2020, 8 , 20286-20293. 2. Zhao, X. Lu, L. Wang, J. Gale and R. Amal, Adv. Mater . 2019, 31 , 1805367.
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