Sulfate‐Functionalized RuFeO_x as Highly Efficient Oxygen Evolution Reaction Electrocatalyst in Acid

Abstract

The design of highly active, stable, and low‐cost electrocatalysts for the oxygen evolution reaction (OER) in proton exchange membrane water electrolyzer remains a challenge. RuO2 shows relatively low cost but poor stability. Here, the critical role of sulfate anion doping in promoting OER activity and stability of RuO2 is reported. Coupled with the Fe cation doping, the sulfate‐functionalized RuFeOx (S‐RuFeOx) displays a remarkable OER performance with a low overpotential of 187 mV at 10 mA cm−2 in acid, and much enhanced stability. The excellent OER activity of S‐RuFeOx is attributed to the dual positive effects that the sulfate dopants weaken the adsorption of the *OOH intermediate, and Fe dopants promote the deprotonation of chemisorbed water molecules to form *OOH. The enhanced stability is in part due to the sulfate dopants which stabilize the lattice oxygen. These results demonstrate that the anion and cation co‐doped RuO2 is a promising candidate for highly efficient OER electrocatalysts.

An indium-induced-synthesis In0.17Ru0.83O2 nanoribbon as highly active electrocatalyst for oxygen evolution in acidic media at high current densities above 400 mA cm−2

“…S13 and S14†) were utilized to obtain double-layer capacitance ( C dl ) and electrochemically active surface area (ECSA). In 0.17 Ru 0.83 O 2 -350 possesses the highest C dl value of as much as 34.16 mF cm −2 , corresponding to the highest density of active sites, 14 which is also closely related to the typical nanoribbon structure. The corresponding ECSA value and the roughness factor (RF) of the above electrocatalysts are listed in Table S6,† which are consistent with the above trend in electrocatalytic OER activity.…”

“…38 The instability of ruthenium dioxide in acidic OER is because Ru can be converted into high-valence ions that are easily dissolved at high oxidation potential, resulting in a sharp decline in performance. 14 As an important component of an electrocatalyst nanoribbon, the O 1s XPS data of In 0.17 Ru 0.83 O 2 -350 and RuO 2 -350 are shown in Fig. 2d and Table S3,† where the peaks located at about 530.12, 531.18 and 532.37 eV are ascribed to lattice oxygen, oxygen defects and adsorbed oxygen, respectively, 40 and the corresponding proportions can be obtained semi-quantitatively.…”

“…Herein, ruthenium dioxide is a benchmark electrocatalyst for acidic OER, and plenty of high-performance ruthenium dioxide-based catalysts have been synthesized by heteroatom doping or surface modification by oxygen or other groups. 12–14 A series of electrocatalysts were prepared by constructing perovskite, bimetallic oxide or spinel structures, such as Pb 2 Ru 2 O 6.5 , 15 [Ru 2– x Pb x ]O 6.5 , Y 2 [Ru 1.6 Y 0.4 ]O 7− δ Sm 2 Ru 2 O 7 , 16 Bi 2.4 Ru 1.6 O 7 , 17 Y 2 [Y x Ru 2− x ]O 7− y , 18 Y 2 Ru 2 O 7− δ , 19 Cu–RuO 2 , 20 Cr 0.6 Ru 0.4 O 2 , 21 Mg–RuO 2 , 22 Co 0.11 Ru 0.89 O 2− δ , 23 Ir 0.7 Ru 0.3 O 2 , 24 RuIrCaO x (ref. 25) and Ni cluster –Ru NWs, 1 realizing an overpotential below 300 mV or even 200 mV at a current density of 10 mA cm −2 .…”

In Situ Investigation on Life‐Time Dynamic Structure–Performance Correlation Toward Electrocatalyst Service Behavior in Water Splitting

“…Therefore, a four‐electron reaction mechanism corresponding to Ni 4+ OOH has been revealed for lattice strained MOF (Figure 6f). Besides, the key reaction intermediates in other electrocatalysts, such as Co*O, [ 64 ] C*O, [ 65 ] and Ru*OOH, [ 66 ] have been extensively studied by in situ FTIR.…”

Rational design of Fe-N-C electrocatalysts for oxygen reduction reaction: From nanoparticles to single atoms

“…Electrochemical energy storage and conversion technology by using a wide range of small molecules containing in the atmosphere such as O 2 or CO 2 have become an important way to develop clean energy devices [3][4][5][6]. Electrochemical reactions mainly involve the following reactions: oxygen reduction reaction (ORR) [7][8][9][10][11][12], oxygen evolution reaction (OER) [13][14][15][16][17][18][19][20], hydrogen evolution reaction (HER) [21][22][23][24][25], and carbon dioxide reduction reaction (CO 2 RR) [26,27]. Electrocatalysts play a key role in these energy conversion reactions, which can reduce the reaction barrier and improve the conversion rate, efficiency and selectivity, promoting the development of efficient catalysts.…”