Facile Synthesis of Sulfur‐Containing Transition Metal (Mn, Fe, Co, and Ni) (Hydr)oxides for Efficient Oxygen Evolution Reaction

Abstract

Transition metal based materials are promising non-noble metal based catalysts for the oxygen evolution reaction (OER). Transition metal (hydr)oxides have been intensively investigated as OER catalysts. Promoting transition metal (hydr)oxides with heteroatoms or using carbon materials as additives can increase the electric conductivity and tailor the nature of active sites to enhance OER activity. We developed a scalable one-step wet chemical method to prepare sulfur-containing transition metal (manganese, iron, cobalt, and nickel) (hydr)oxides coupled with carbon nanotubes as additives to tailor OER performance. Facilitated OER kinetics, enhanced intrinsic activity, and high electrochemically active surface area derived from sulfur promotion with/without carbon nanotubes addition together with the nanostructure of the materials led to decent OER performance. Sulfur-containing cobalt (hydr)oxide achieved a low overpotential of 0.38 V at 10 mA cm À 2 , a low Tafel slope of 66 mV dec À 1 , and good stability.Electrochemical water splitting is a promising technology to produce hydrogen (H 2 ) as a green energy carrier. [1][2][3] However, a practical application of the technology is hampered by the sluggish kinetics (high overpotential) of the anodic oxygen evolution reaction (OER). [4,5] Various catalysts have been investigated to accelerate the kinetics and reduce the overpotential of OER, [3][4][5][6] and iridium/ruthenium based materials are among the most active catalysts for OER in acid conditions and also possess relatively high activity in basic conditions. [7][8][9][10] However, the scarcity and the high cost of iridium/ruthenium impede their large-scale utilization in industry. Transition metal based materials have been intensively investigated to substitute iridium/ruthenium based materials due to their high abundance in the earth's crust and their lower costs. [11][12][13] Diverse strategies have been developed to improve the OER performance of transition metal based materials. [13,14] Such strategies include, 1) creating nanostructures and reducing the catalyst size to raise the exposure of active sites and the electrochemically active surface area; [15,16] 2) increasing the electric conductivity by coupling the catalyst with conductive compounds like nickel foam, [17] transition metal chalcogenides, [18] and carbon materials; [19] 3) tailoring the intermediate adsorption and the intrinsic activity by elemental doping, [20,21] defect engineering, [22] and coating with carbon materials. [23] Recent studies showed that transition metal based materials, MX a Y b (M = transition metal, X, Y=O, S, Se, N, and P), possess good OER performance. [24][25][26][27][28] The incorporation of a second element can optimize the electronic structure, create active sites, and facilitate the intermediate adsorption to achieve high electric conductivity, high exposure of active sites, and high intrinsic activity for decent electrochemical oxygen evolution performance. [24][25][26][27][28] However, MX a Y b type materials are...

An Fe-doped Co-oxide electrocatalyst synthesized through a post-modification method toward advanced water oxidation

“…24 In addition, non-noble metals can be used to replace noble metals for the electrocatalytic OER. 25,26 Until now, it has been reported that many non-noble metals and their derivatives such as carbides, 27,28 oxides, 29,30 phosphides, 31,32 nitride, 33,34 sulfides 35,36 and so on have been used to prepare OER electrocatalysts, whose behaviors can be compared to those of noble metal catalysts. Based on the further development of the above-mentioned non-precious metal catalysts, bimetal-based catalysts, as a new research frontier in catalysis, have attracted widespread attention due to their excellent electrochemical performance.…”

Particle size-controlled synthesis of high-performance MnCo-based materials for alkaline OER at fluctuating potentials

“…oxides and even metal-free systems have been widely studied under alkaline conditions. [5][6][7][8][9][10][11][12] Inspired by nature (Mn-based clusters in PS II), manganese-based materials are especially interesting. 13 Bergman et al 14 as well as Smith et al 15 pointed out in early studies that the electronic properties and structure of the manganese oxides have to be optimized to achieve a superior OER performance.…”

NiFe2O4/NiFeP Heterostructure Grown on Nickel Foam as an Efficient Electrocatalyst for Water Oxidation

“…[27] Transition metal oxides (TMOs) and transition metal phosphides (TMPs) have been widely concerned. [28][29][30][31][32] Among them, TMOs are considered as high active electrocatalysts for OER , [33,34] but the activity is difficult to be further improved due to their easy agglomeration in the catalytic process and poor electrical conductivity. [35,36] Researches have shown that the combination of TMOs with conductive substrates such as Ni foam (NF), Ti mesh and carbon cloth (CC) is a feasible approach to improve the electrical conductivity of TMOs.…”