Probing the relationship between bulk and local environments to understand impacts on electrocatalytic oxygen reduction reaction

Electrocatalytic oxygen evolution activity of surfactant-free cobalt- and manganese-based spinel oxide nanoparticles in acid

“…The m H+ is not zero in the RHE scale, which indicates the involvement of non-coupled proton electron transfer processes before or at the OER rate-limiting step. 61 Higher m H+ values are observed for Co 1.27 Mn 1.27 Fe 0.46 O 4 , and electron densities at Co sites are decreased. These indicate that the electron interaction alters the p K a of the M–OH or M–OH 2 center and affects the OER kinetics.…”

Recent Advances with Biomass‐Derived Carbon‐Based Catalysts for the High‐Efficiency Electrochemical Reduction of Oxygen to Hydrogen Peroxide

“…In previous studies, it has been observed that the selectivity and activity of 2e À ORR catalysts are strongly affected by the pH of the electrolyte, so it is necessary to understand the effect of pH for the design of efficient catalysts in different electrolytes. [44] As mentioned above, the overall reaction and thermodynamic potential versus RHE of the 2e À ORR are as follows: at pH…”

“…In previous studies, it has been observed that the selectivity and activity of 2e − ORR catalysts are strongly affected by the pH of the electrolyte, so it is necessary to understand the effect of pH for the design of efficient catalysts in different electrolytes. [ 44 ] As mentioned above, the overall reaction and thermodynamic potential versus RHE of the 2e − ORR are as follows: at pH < 11.6, O 2 + 2 H + + 2e − → H 2 O 2 , E 0 (O 2 /H 2 O 2 ) = 0.70 V versus RHE. However, when pH = 13, higher than the acid dissociation constant of H 2 O 2 (p K a = 11.7), the product of 2e − ORR changes from H 2 O 2 to HO 2 − , and the overall reaction can be expressed as: O 2 + H 2 O + 2e − → HO 2 − + OH − , at pH = 13, E 0 (O 2 /HO 2 − ) = 0.74 V versus RHE.…”

Mass Transport Modifies the Interfacial Electrolyte to Influence Electrochemical Nitrate Reduction

“…In ongoing efforts to improve activity and ammonia selectivity of electrochemical NO 3 RR, researchers have mainly focused on improving electrocatalysts. However, it has been increasingly recognized that the reaction microenvironment, which contains both the electrocatalyst and the interfacial electrolyte between the electrocatalyst and the bulk electrolyte, directly influences electrocatalytic reduction reactions (e.g., carbon dioxide reduction reaction, CO 2 RR; oxygen reduction reaction, ORR; hydrogen evolution reaction, HER). − Specifically, the interfacial electrolyte is composed of a compact electrical double layer (EDL) that extends a few nanometers away from the electrode surface and a diffusion layer that spans up to a few hundred microns into the bulk electrolyte . As the immediate environment where reactions take place, the interfacial electrolyte physicochemical properties (e.g., electric potential, pH, solute concentrations) may differ drastically from the bulk. ,, Among these properties, electric potential serves as the thermodynamic driving force for electrode reactions, and pH indicates the abundance of proton sources, both of which influence reaction activity and selectivity.…”