S‐Doping Triggers Redox Reactivities of Both Iron and Lattice Oxygen in FeOOH for Low‐Cost and High‐Performance Water Oxidation

Abstract

Developing low‐cost and highly efficient earth‐abundant oxygen evolution reaction (OER) electrocatalysts via an energy‐ and time‐saving method is of great significance to the generation of H2 from electrochemical water splitting, which is highly desirable but still challenging. Herein, a one‐step route to in situ grow S‐doped FeOOH vertical nanosheets on iron foam (IF) in 20 min under room temperature is shown. This facile and ultrafast method effectively modifies the surface of the IF into an S‐doped FeOOH layer, and a full‐Fe electrode (S‐FeOOH/IF) is achieved. Systematic experiments and characterizations demonstrate that the redox reactivities for both of the iron and lattice oxygen in FeOOH are sufficiently activated, leading to the dramatically improved intrinsic OER activity. The as‐obtained S‐FeOOH/IF exhibits a fascinating OER performance with a low overpotential of 244 at 10 mA cm−2. This work affords an efficient surface engineering strategy to drive commercial IF into cost‐efficient and robust earth‐abundant electrocatalysts for water oxidation, which has important implications for clean H2 production through a low‐carbon and environmentally friendly route.

Interface Engineering of Hollow CoO/Co4S3@CoO/Co4S3 Heterojunction for Highly Stable and Efficient Electrocatalytic Overall Water Splitting

“…When the potential is 1.42 V, a new peak (586 cm –1 ) gradually appears, and the intensity of this peak gradually increases with the increase of the potential, which is attributed to the key intermediate CoOOH of CoO/Co 4 S 3 @CoO/Co 4 S 3 . − The CoOOH generated by the nucleophilic attack of the *OH species releases oxygen and regenerates the active site after further proton coupling and electron transfer. Figure b shows the evolution of the two intermediates CoOOH and Co-OO-Co under conditions of 1.42 V. When the reaction time is 200 s, the peak of the CoOOH active intermediate at 586 cm –1 appears . As time goes on, the peak of CoOOH gradually becomes obvious, demonstrating that the O 2 produced by the OER process is significantly released under these reaction conditions.…”

A self-supported S-doped Fe-based organic framework platform enhances electrocatalysis toward highly efficient oxygen evolution in alkaline media

“…Note that the broad peak at 673 cm −1 collected can be assigned to the appearance of Fe–O vibrations in the FeOOH phase, proved as the active species for the OER. 65 Interestingly, S 0.05 –Fe-BTB/NF can evolve into surface FeOOH completely under a low potential of 1.5 V (Fig. S14b†), indicating that the active FeOOH species can more easily form in the S-doped Fe-BTB/NF catalyst at lower potentials than the pristine Fe-BTB/NF catalyst.…”

Efficient and durable S-doped Ni/FeOOH electrocatalysts for oxygen evolution reactions

“…3a) can be divided into peaks at 161.3, 162.6 and 168.4 eV, which are attributed to S 2p 3/2 , S 2p 1/2 , and sulfate. 9 Fig. 3b–d compare the high-resolution XPS spectra of Ni 2p, Fe 2p, and O 1s between Ni/FeOOH@NFF and S–Ni/FeOOH@NFF.…”

“…Therefore, developing high-efficiency, stable and low-cost catalysts is still a huge challenge, especially via energy-saving methods. 5–9…”

“…Therefore, developing high-efficiency, stable and low-cost catalysts is still a huge challenge, especially via energy-saving methods. [5][6][7][8][9] In recent years, transition metal-based electrocatalysts have been considerably developed, such as oxides, hydroxides, chalcogenides, metal-organic frameworks (MOFs) and nitrides. [10][11][12][13][14][15][16][17][18] Among them, NiFe-based compounds could win out as highly efficient OER catalysts, because the synergistic effect can provide appropriate electronic structures to bind the OER intermediates.…”