Over 21.0% faradaic efficiency of ambient ammonia production: Photoelectrocatalytic activity of MOF-235

• Published in: Applied materials today 2022-08, Vol.28, p.101540, Article 101540
• Main Authors: Camargo, Luan Pereira, da Silva, Paulo Rogério Catarini, Batagin-Neto, Augusto, Klobukoski, Vanessa, Vidotti, Marcio, Dall'Antonia, Luiz Henrique
• Format: Article
• Language: English
• Subjects: Nanoscale materials; Photoelectrocatalysis; Semiconductor; Solvothermal synthesis
• ISSN: 2352-9407; 2352-9415
• DOI: 10.1016/j.apmt.2022.101540

•MOF-235 as highly efficient NRR photoelectrocatalyst under UV light•MOF-235 exhibits high Faraday efficiency for NRR under ambient conditions•The active sites of MOF-235 are related with the trinuclear-oxocentered iron In recent years, the Haber-Bosh process's ammonia synthesis has shown a lot of energy consumption and significant CO2 emissions. In this sense, the photoelectrochemical production of NH3 via dinitrogen fixation has been showing a promising strategy. Thus, in this work, ammonia production under photoelectrocatalytic condition was carried out using the metal-organic iron terephthalate structure (MOF-235), obtained by a simple and low-cost process (solvothermal). The results indicated greater activity for the nitrogen reduction reaction (NRR) compared to the hydrogen reduction reaction (HRR), in addition to a high yield of NH3 0.716 µg h−1 cm−2 and Faradaic efficiency greater than 21.0% at - 0.2 V vs reversible hydrogen electrode in 0.1 mol L−1 Na2SO4 electrolyte. It is believed that the good results of MOF-235 during NRR are related to a high specific area of MOF, making available active sites of trinuclear-oxocentered iron in abundance. The material homogeneity in the electrode and the excellent light absorption were also decisive factors for the supply of high energy electrons necessary for ammonia production. [Display omitted]