Highly Efficient Oxygen Evolution by a Thermocatalytic Process Cascaded Electrocatalysis Over Sulfur‐Treated Fe‐Based Metal–Organic‐Frameworks

Abstract

The oxygen evolution reaction (OER) is a bottleneck process for water splitting and finding highly efficient, durable, low‐cost, and earth‐abundant electrocatalysts is still a major challenge. Here a sulfur‐treated Fe‐based metal–organic‐framework is reported as a promising electrocatalyst for the OER, which shows a low overpotential of 218 mV at the current density of 10 mA cm−2 and exhibits a very low Tafel slope of 36.2 mV dec−1 at room temperature. It can work on high current densities of 500 and 1000 mA cm−2 at low overpotentials of 298 and 330 mV, respectively, by keeping 97% of its initial activity after 100 h. Notably, it can achieve 1000 mA cm−2 at 296 mV with a good stability at 50 °C, fully fitting the requirements for large‐scale industrial water electrolysis. The high catalytic performance can be attributed to the thermocatalytic processes of H+ capture by –SO3 groups from *OH or *OOH species, which cascades to the electrocatalytic pathway and then significantly reduces the OER overpotentials.

Carbon nanotube supported PtO nanoparticles with hybrid chemical states for efficient hydrogen evolution

“…To produce hydrogen, electrochemical water splitting is typically used as an effective way without CO 2 emission, which has received particular attention [3][4][5]. It includes two half reactions, oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) [6][7][8][9][10][11][12]. By now various catalysts have been used for HER in acidic solution and have achieved high performance [10][11][12].…”

“…By now various catalysts have been used for HER in acidic solution and have achieved high performance [10][11][12]. However, many excellent catalysts for OER typically work in alkaline solution [6,8], leading to mismatch of the working electrolyte for both OER and HER. Thus it is of great significance to develop efficient electrocatalysts working in alkaline solution.…”

Engineering the Activity and Stability of MOF‐Nanocomposites for Efficient Water Oxidation

“…The stability of specific MOF catalytic systems for OER and HER varies significantly as a function of the organic ligands and their interaction with the metal cations. For instance, recent investigation of the MOF‐74 system for OER revealed (oxy)hydroxides as active sites, [ 17 ] while other MOF systems such as CoBDC–Fc–NF, [ 18 ] A 2.7 B‐MOF‐FeCo 1.6 , [ 19 ] and FeMOFs‐SO 3 [ 20 ] have been found to preserve their original structure during and/or post OER. To investigate the stability of our NiFe‐MOF/G catalyst surface we characterized the post‐OER composition of these sample by XPS, HRTEM, and Raman immediately after 10 h OER reaction (Figure S14, Supporting Information).…”

MOFs‐Derived Carbon‐Based Metal Catalysts for Energy‐Related Electrocatalysis

“…Compared with SACs, MOFs-derived metal NPs have been widely applied in OER electrocatalysis. [122,141,142] Zhang et al [106] prepared Co NPs confined in 1D mesoporous carbon nanofibers (CoNC-CNF) and applied in OER (Figure 11a). As shown in Figure 11b,c, these 1D carbon nanofibers encased Co NPs could reach the current density of 10 mA cm −2 at an overpotential of 450 mV and Tafel slope of 94 mV dec −1 .…”