Affiliation:
1. Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology Ben-Gurion University of the Negev Beer-Sheva 8410501 Israel
2. BioTechMed Center and Department of Pharmaceutical Technology and Biochemistry ul. Narutowicza 11/12 Gdańsk University of Technology 80-233 Gdańsk Poland
Abstract
AbstractElectrocatalytic nitrite reduction (eNO2RR) is a promising alternative route to produce ammonia (NH3). Until now, several molecular catalysts have shown capability to homogeneously reduce nitrite to NH3, while taking advantage of added secondary‐sphere functionalities to direct catalytic performance. Yet, realizing such control over heterogeneous electrocatalytic surfaces remains a challenge. Herein, we demonstrate that heterogenization of a Fe‐porphyrin molecular catalyst within a 2D Metal–Organic Framework (MOF), allows efficient eNO2RR to NH3. On top of that, installation of pendant proton relaying moieties proximal to the catalytic site, resulted in significant improvement in catalytic activity and selectivity. Notably, systematic manipulation of NH3 faradaic efficiency (up to 90 %) and partial current (5‐fold increase) was achieved by varying the proton relay‐to‐catalyst molar ratio. Electrochemical and spectroscopic analysis show that the proton relays simultaneously aid in generating and stabilizing of reactive Fe‐bound NO intermediate. Thus, this concept offers new molecular tools to tune heterogeneous electrocatalytic systems.
Funder
HORIZON EUROPE European Research Council
Israel Science Foundation