Bioinspired electrocatalytic reduction of nitric oxide by immobilized heme groups

Disproportionation of hydroxylamine by water-soluble iron(III) porphyrinate compounds

“…The water-soluble [Fe III (TPPS)] 3À is an electrocatalyst for the latter reduction process at pH 4.5 or 6.7, with HA and N 2 O appearing as main products under controlled conditions [3]. More recently, it has been shown that heme groups can electrocatalyze the specific reduction of NO to HA or N 2 O when immobilized on pyrolytic graphite [4]. Metal-catalyzed reverse processes involving the oxidation of NH 3 to NO À 2 have also been described with similar proposed intermediates, namely nitroxyl (HNO/NO À ), NO and NO + , as well as HA [5,6].…”

Selective electrochemical reduction of nitric oxide to hydroxylamine by atomically dispersed iron catalyst

“…Much effort has thus been devoted to identifying the physicochemical parameters that govern the NORR selectivity on single-site and metallic surfaces 11 , 21 – 25 . Improved understanding on the NORR electrocatalysis by heme (iron protoporphyrin IX) has been reached via its controlled immobilisation on a graphite surface 21 – 23 . Two different NORR pathways were identified: pH-dependent (NH 2 OH formation) and pH-independent (N 2 O formation) pathways, the selectivity of which is affected by electrolyte pH, NO concentration, and electrode potential.…”

Alternating Layers of Iron(III) Tetra(N‐methyl‐4‐pyridyl)‐porphyrin and Copper Tetrasulfonated Phthalocyanine for Amperometric Detection of 4‐Nitrophenol in Nanomolar Levels

“…Such good sensitivity of 0.014 mA L nmol À1 can be attributed to the efficiency of the electron transfer between CuTSPc/FeT4MPyP and 4-NP. Furthermore, the detection limit and sensitivity of the present work are better when compared to the reported works involving modified electrodes [15,16,34,46,47].…”

“…However, it is still unclear why such peak is not observed for directly adsorbed heme, for example, layer-by-layer electrostatic assembled films. Mayer and coworkers also verified the electrocatalytic activity of the electrodes for reduction of nitrite with similar layer-by-layer electrostatic assembled films (Fe-3TRPyP/CuTSPc) at phosphate buffer at pH 6.8 and acetate buffer at pH 4.7 [34,35], when the cathodic current increased linearly as a function of the analyte concentration at À 0.85 V vs SHE. However, as already mentioned, the authors did not affirm, which species could be associated with the electrocatalytic process.…”