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

Abstract

For the first time, the manganese gallide (MnGa4) served as an intermetallic precursor, which upon in situ electroconversion in alkaline media produced high‐performance and long‐term‐stable MnOx‐based electrocatalysts for water oxidation. Unexpectedly, its electrocorrosion (with the concomitant loss of Ga) leads simultaneously to three crystalline types of MnOx minerals with distinct structures and induced defects: birnessite δ‐MnO2, feitknechtite β‐MnOOH, and hausmannite α‐Mn3O4. The abundance and intrinsic stabilization of MnIII/MnIV active sites in the three MnOx phases explains the superior efficiency and durability of the system for electrocatalytic water oxidation. After electrophoretic deposition of the MnGa4 precursor on conductive nickel foam (NF), a low overpotential of 291 mV, comparable to that of precious‐metal‐based catalysts, could be achieved at a current density of 10 mA cm−2 with a durability of more than five days.

A soft molecular 2Fe–2As precursor approach to the synthesis of nanostructured FeAs for efficient electrocatalytic water oxidation

“…Additionally, their OER activities are comparable to those of the state-of-the-art electrocatalysts such as RuO 2 and IrO 2 . 8 Among them, transition metal (TM) oxides and oxyhydroxides, 9 phosphates, 10 borophosphates, 11 phosphites, 12 intermetallics, 13 chalcogenides, 14,15 and pnictides [16][17][18] have lately been used for the OER, HER and overall water splitting. The latter, notably nitrides and phosphides, have been explored extensively due to their high electroconductivity and greater resistance to harsh electrolyte environments, i.e.…”

“…One of the i Pr groups in the ligand is disordered over two positions, and hence only one configuration is shown. Selected bond lengths [Å] and angles [ ]: As1-As1 i 2.3447(5), Fe1-As1 2.4023(4), Fe1-As1 i 2.4087(4), Fe1-N1 2.0085(18), Fe1-N2 2.0096(18), Fe1/Fe1 i 4.201, N1-Fe1-N2 95.95(7), As1-Fe1-As1 i 60.9969(13), and Fe1-As1-Fe1 i 121.664(12). Symmetry operation for (i): Àx + 1, Ày + 1, Àz + 1 (crystal data and structure refinement are shown in Tables S1-S4 †).…”

Electrocatalysts Based on Transition Metal Borides and Borates for the Oxygen Evolution Reaction

“…OER process is still ill-characterized.E ffective methodologies that could be applied to this problema re isotopic labelinga nd in situ techniques. [101,102] The unsatisfactory intrinsic activity of TMBs is ab ottleneck for their commercialization, and the main approach to solve this problem is doping with other elements.H owever,t he doping process is guideless, thus theoretical calculation approaches are required for design of TMBs catalysts for OER.…”

Comprehensively Probing the Contribution of Site Activity and Population of Active Sites toward Heterogeneous Electrocatalysis

“…[3,9.10] In connection with advanced projects for significantly increasing the efficiency of water electrolysis, two noticeable research domains are adopted. The first one is to create high surface areas of electrocatalysts for improving the number of exposed active sites, while the second one is to design a new electrocatalyst for enhancing intrinsic activity (Table ) . Loading or in‐situ generation of electrocatalysts on two‐dimensional/three‐dimensional frameworks, such as graphene derivatives or metal‐organic frameworks, bears large specific area for improving the exposure of active sites.…”