A Molecular Approach to Manganese Nitride Acting as a High Performance Electrocatalyst in the Oxygen Evolution Reaction

Abstract

The scalable synthesis of phase-pure crystalline manganese nitride (Mn N ) from a molecular precursor is reported. It acts as a superiorly active and durable electrocatalyst in the oxygen evolution reaction (OER) from water under alkaline conditions. While electrophoretically deposited Mn N on fluorine tin oxide (FTO) requires an overpotential of 390 mV, the latter is substantially decreased to merely 270 mV on nickel foam (NF) at a current density of 10 mA cm with a durability of weeks. The high performance of this material is due to the rapid transformation of manganese sites at the surface of Mn N into an amorphous active MnO overlayer under operation conditions intimately connected with metallic Mn N , which increases the charge transfer from the active catalyst surface to the electrode substrates and thus outperforms the electrocatalytic activity in comparison to solely MnO -based OER catalysts.

Boosting Water Oxidation through In Situ Electroconversion of Manganese Gallide: An Intermetallic Precursor Approach

“…Ac loser look at the edge of the nanostructure in HRTEM suggested al attice spacing of 0.7 nm, which can be assigned to the (001) plane of birnessite d-MnO 2 .F urthermore,t he distance of 0.26 nm could be ascribed to (301) planes of feitknechtite b-MnOOH or (311) planes of hausmannite a-Mn 3 O 4 structures,w hich is in accordance with the PXRD.T his observation is quite different from other Mn-based materials where an amorphous shell is usually formed on ac rystalline core. [12] The FTIR spectrum after OER exhibited bands corresponding to surface hydroxylation, Mn À OH as well as Mn À O, further confirming the derived conclusions ( Figure S40). TheM nKedge XANES spectrum of MnGa 4 after OER was measured with several manganese standards and used as ab asis for comparison ( Figure 3c;F igure S41).…”

“…Thus,itisvery challenging and attractive to gain synthetic access to reliably active MnO x materials other than by starting from common manganese oxides;these new materials could display promising catalytic activities and provide profound insights on the required MnO x structures for OER. [12] We have discovered that intermetallic manganese phases could serve as an ew class of precursor materials for the production of MnO x catalysts with superior performance and durability in electrocatalytic OER.…”

Stannites – A New Promising Class of Durable Electrocatalysts for Efficient Water Oxidation

“…Therefore, many of the oxides and most of the non‐oxidic materials are merely precatalysts for the OER . Even though the anion is often exchanged or depleted from the electrocatalytic active structure, it plays a significant role in tuning the properties of the active catalyst either by creating high surface areas and defects through leaching or by providing a conductive core …”

MOF‐Derived Copper Nitride/Phosphide Heterostructure Coated by Multi‐Doped Carbon as Electrocatalyst for Efficient Water Splitting and Neutral‐pH Hydrogen Evolution Reaction

“…Nevertheless, these MOF derived materials are less prefered as electrocalalyst because of their complicated preparation protocols and it mainly suffers from large overpotential with poor electrocatalytic performance . Recently in searching of efficient catalyst, nitrides and phosphides of first‐row non‐noble transition metals have been explored as a unique electrocatalyst for HER or OER with efficient activity and stability . Although copper an earth abundant and inexpensive catalyst for overall water splitting is inspired from the functions involved in copper based metalloenzymes have shown promising electrocatalytic performance, however, copper oxide based nanomaterials are usually not considered as good electrocatalyst and thus limited in practical applications due to their low conductivity and causes severe aggregation when exposed in alkaline medium, and thus it results in low catalytic activity.…”