Evaluation of electrodeposited α-Mn 2 O 3 as a catalyst for the oxygen evolution reaction

Abstract

-Mn 2 O 3 is of interest as a low-cost and environmentally benign electrocatalyst for the Oxygen Evolution Reaction (OER) in the process of water splitting. Mechanically stable -Mn 2 O 3 electrodes are prepared by annealing of galvanostatically deposited MnOOH x layers on F:SnO 2-coated glass. The overpotential  to achieve a current density of j = 10 mAcm-2 decreases from 590 to 340 mV with increasing layer thickness. Differential capacitance measurements reveal that this high OER activity can be attributed to the large electrochemically active surface area (ECSA), which scales linearly with the thickness of these highly porous and electrolyte-permeable films. The oxide layers exhibit a reversible oxidation behavior from Mn(III)  Mn(IV). Although the intrinsic activity is small compared to that of other OER catalysts, such as NiFeO x , the combination of high ECSA and good electrical conductivity of these α-Mn 2 O 3 films ensures that high OER activities can be obtained. The films are found to be stable for >2 h in alkaline conditions, as long as the potential does not exceed the corrosion potential of 1.7 V vs. RHE. These findings show that α-Mn 2 O 3 is a promising OER catalyst for water splitting devices.

The role of ultra-thin MnOx co-catalysts on the photoelectrochemical properties of BiVO4 photoanodes

“…[5][6][7][8] To overcome this, various cocatalysts, e.g., RuO 2 , Ni/FeOOH, NiFeO x , CoPi, MnO x , etc. have been applied in order to modify the surface of metal oxide semiconductors, [9][10][11][12][13][14][15][16] which resulted in an improvement of the photocurrent. 14,[17][18][19][20][21][22][23][24][25] Indeed, most metal oxide photoanodes showing high photocurrent (>5 mA cm À2 ) are decorated with additional co-catalysts.…”

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

“…This is attributed to the oxidation of Mn 2+ /Mn 3+ to higher oxidation states and is well known for Mn-based materials. [23][24][25][26] Thec hronopotentiometric (CP) responses of both Mn 3 N 2 and Mn 2 O 3 were measured in alkaline OER conditions maintaining ac onstant current of 1mAcm À2 and 10 mA cm À2 .Remarkably,Mn 3 N 2 was found to be very stable over 3hours with ac onstant overpotential of 330 mV (at 1mAcm À2 )a nd 530 mV (10 mA cm À2 ). However,M n 2 O 3 required an overpotential of 430 mV to maintain 1mAcm À2 and showed ac onstant rise in overpotential within 3hwhile maintaining ac urrent of 10 mA cm À2 (Supporting Information, Figure S12).…”

“…Thep eaks appeared in the same potential region as that of FTOa nd could therefore be well attributed to the oxidation of Mn 2+ /Mn 3+ to higher valencies excluding the possible influence of NF in OER catalysis. [23][24][25][26]29] Subsequently,t he long-term stability of Mn 3 N 2 was tested in strongly alkaline OER conditions maintinaing ac urrent of 10 mA cm À2 .U nexpectedly,t he stability exceeded aw eek (180 h) with exceptionally sustained overpotentials (ca. 290 mV), which makes it the best durable system known among Mn-based OER catalysts (Figure 3b).…”

Designing Aqueous Organic Electrolytes for Zinc–Air Batteries: Method, Simulation, and Validation

“…Similarly, the EMD catalyst material (blue) shows no response below 1.5 V, in agreement with low activity of electrodeposited manganese oxide toward the OER below 1.5 V in alkaline solution. [81] The current uptick above 1.5 V can be attributed to corrosion of the GC substrate with a possible contribution from the OER, which is expected to onset between 1.5 and 1.6 V. [82] The CNT film electrode current (black) presents the onset of an oxidation process at ≈1.2 V, which aligns with the organic species oxidation process observed on pc-Pt ( Figure S4, Supporting Information). A small shoulder in the current is visible at 1.45 V. The EMD+CNT film current (red) traces the CNT current until ≈1.45 V. Above this potential, EMD+CNT shows close to an exponential increase in current in both nitrogensaturated and oxygen-saturated electrolyte.…”