Large‐Scale Synthesis of Spinel Ni_xMn_3‐xO₄ Solid Solution Immobilized with Iridium Single Atoms for Efficient Alkaline Seawater Electrolysis

Abstract

Seawater electrolysis not only affords a promising approach to produce clean hydrogen fuel but also alleviates the bottleneck of freshwater feeds. Here, a novel strategy for large-scale preparing spinel Ni x Mn 3-x O 4 solid solution immobilized with iridium single-atoms (Ir-SAs) is developed by the sol-gel method. Benefitting from the surface-exposed Ir-SAs, Ir 1 /Ni 1.6 Mn 1.4 O 4 reveals boosted oxygen evolution reaction (OER) performance, achieving overpotentials of 330 and 350 mV at current densities of 100 and 200 mA cm -2 in alkaline seawater. Moreover, only a cell voltage of 1.50 V is required to reach 500 mA cm -2 with assembled Ir 1 /Ni 1.6 Mn 1.4 O 4 ‖Pt/C electrode pair under the industrial operating condition. The experimental characterizations and theoretical calculations highlight the effect of Ir-SAs on improving the intrinsic OER activity and facilitating surface charge transfer kinetics, and evidence the energetically stabilized *OOH and the destabilized chloride ion adsorption in Ir 1 /Ni 1.6 Mn 1.4 O 4 . This work demonstrates an effective method to produce efficient alkaline seawater electrocatalyst massively.

Recent Progress on Non‐Carbon‐Supported Single‐Atom Catalysts for Electrochemical Conversion of Green Energy

“…Reproduced with permission. [ 131 ] Copyright 2022, Wiley‐VCH. d) Schematic diagram of the preparation process of the PtSA/Cs 2 SnI 6 catalyst.…”

“…[ 130 ] Chen and co‐workers synthesized Ni 1.6 Mn 1.4 O 4 immobilized with Ir single atoms (Ir 1 /Ni 1.6 Mn 1.4 O 4 ) via the impregnation method. [ 131 ] As shown in Figure 3c, the support of spinel Ni 1.6 Mn 1.4 O 4 was first synthesized using the sol–gel method and dispersed uniformly in ethanol. Subsequently, IrCl 3 solution was poured into the above dispersion dropwise, and Ir 1 /Ni 1.6 Mn 1.4 O 4 was obtained by thermal treating at 400 °C for 2 h under argon (Ar).…”

“…c) The schematic diagram for the synthetic procedure of the Ir 1 /Ni 1.6 Mn 1.4 O 4 . Reproduced with permission [131]. Copyright 2022, Wiley-VCH.…”

Elucidation of single atom catalysts for energy and sustainable chemical production: Synthesis, characterization and frontier science

“…• Carbon [295] • CMK [324] • Co(OH) 2 [106] • CoO x [306] • FeO x [24,324] • Fe 2 O 3 [227] • Fe 3 O 4 [325] • MgAl 2 O 4 [326] • NiFeP [327] • NiMnO [328] • NiO [306] • Porous organic polymer [245] • WO 3 [329] • ZIF [245,247,330] • Atom trapping [326] • Co-precipitation [24,324] • Electrochemical method [106] • Facile method [327] • IWI [245,295] • Micro-gas blasting [306] • Photochemical method [227,329] • Pyrolysis-assisted method [247,330] • Mass-selected soft-land [325] • Wet impregnation [328,331] • CO Oxidation [24] • HER [106] • Hydrochlorination [295] • Hydrogenation [245,331] • N 2 O decomposition [326] • ORR [330] • OER [106,247,323,327] • Solar water oxidation [227,329] • WGS reaction…”

Polarization Manipulation of NiO Nanosheets Engineered with Fe/Pt Single Atoms for High-Performance Electrocatalytic Overall Alkaline Seawater Splitting

“…Besides, MnO possesses a similar structure to NiO, resulting in easily substituting Ni atoms for Mn atoms to achieve Mn-doped NiO nanosheets. In addition, inspired by the impressive selectivity and stability of Mn-based oxides in the acidic electrolyte in published reports and our previous work, Mn-based oxides represent good selectivity in the alkaline electrolyte due to the similar chlorine ion-adsorbing process by surface polarization. , Therefore, to further evaluate the effect of surface charge polarization on electronic metal–support interaction, we prepared Mn-doped NiO nanosheets (denoted as Mn_NiO) engineered with Pt/Fe single atoms (denoted as Pt 1 /Mn_NiO and Fe 1 /Mn_NiO, respectively). The electrocatalytic performance and structural robustness with/without Mn doping are necessarily measured, where Pt 1 /Mn_NiO and Fe 1 /Mn_NiO separately reveal enhanced HER and OER activity as well as long-term durability in alkaline seawater.…”