Nickel‐Doping Effect on Mn₃O₄ Nanoparticles for Electrochemical Water Oxidation under Neutral Condition

Abstract

As the demand for energy has dramatically increased in the past decade, electrochemical water splitting has been regarded as an attractive approach to produce renewable hydrogen energy. However, large overpotentials of oxygen‐evolving reaction (OER) is a key bottleneck for practical application. Thus, water‐oxidizing electrocatalysts with low cost and high efficiency should be developed. Here, 5 nm‐sized Mn3O4 nanoparticles (NPs) are synthesized by a hydrothermal method, which is appropriate for large‐scale production. To further improve their performance, various 3d transition metal elements are successfully doped in Mn3O4 NPs. Ni‐doped Mn3O4 NPs exhibit the highest efficiency among the Mn3O4 NPs doped with various elements. Based on structural analysis, the Ni‐doping process leads to the lattice distortion of their tetragonal spinel structure and it strongly correlates with the enhancement of OER activity. The overpotential at the current density of 10 mA cm–2 is 524 and 458 mV for pristine and 5 at% doped Mn3O4 NPs under neutral condition. The heteroatom‐doping process in sub‐10 nm‐sized nanocatalysts is expected to be a promising methodology to induce distorted structure related to active species. Thus, it can be effective to improve catalytic performance of various heterogeneous nano‐catalysts.

Nanosized high entropy spinel oxide (FeCoNiCrMn)3O4 as a highly active and ultra-stable electrocatalyst for the oxygen evolution reaction

“…17) and Mn 3 O 4 (ref. 18)) with unique electroactive redox pairs and good corrosion resistance in an alkaline environment have been confirmed as excellent OER electrocatalysts. 19 Moreover, the electrocatalytic performance of the spinel oxide can be further improved by element doping to tune the electronic structure and enhance conductivity.…”

Peroxymonosulfate activation by Co-doped magnetic Mn3O4 for degradation of oxytetracycline in water

“…1e-h). The SEM results showed that the surface of Fe 200), ( 103), ( 211), ( 004), ( 220), ( 105), (321), ( 224) and (400), respectively , [41]. The illustration in Fig.…”

Highly efficient OER catalyst enabled by in situ generated manganese spinel on polyaniline with strong coordination

“…[13][14][15][16] Among the multitudinous electrode materials investigated to date, manganese oxides, as a result of their numerous advantages such as low cost, low toxicity, abundant resources and rich redox state in particular, are extremely attractive. [17][18][19][20][21] It has been reported that Mn cations with Mn 3+ valence manifest optimum catalytic activity towards the OER. 19,20,22,23 Mn 3 O 4 can effectively catalyze the OER in alkaline media due to its variable valence state and coordination structure.…”

“…[17][18][19][20][21] It has been reported that Mn cations with Mn 3+ valence manifest optimum catalytic activity towards the OER. 19,20,22,23 Mn 3 O 4 can effectively catalyze the OER in alkaline media due to its variable valence state and coordination structure. 22,23 Nevertheless, the principal problems are that pure Mn 3 O 4 has poor conductivity (10 −7 -10 −8 S cm −1 ) and small specific surface area as well as significant agglomeration, 18,24,25 which will expose few active sites, resulting in inferior catalytic performance.…”