Intercalation of cobalt cations into Co₉S₈ interlayers for highly efficient and stable electrocatalytic hydrogen evolution

Abstract

Non-noble metal based electrocatalysts for hydrogen evolution reactions hold great potential for commercial applications. However, effective design strategies are highly needed to manipulate the catalyst structures for high activity and...

NiFeOOH-Co9S8-Intercalated Nanostructure Arrays for Energy-Efficient H2 Production and Sulfion Oxidation at High Current Density

“…The Co 2p peak at 782.8 eV and a satellite peak at 788.3 eV supported the formation of Co 9 S 8 (Figure C). The Co 2p peak for Co 9 S 8 is reported to be observed around 781.5 eV in the literature . The minor upfield shift (1.3 eV) of the peak in the current sample may possibly be attributed to the interaction of Co 9 S 8 with NiFeOOH in the heterostructure and oxide doping of the former .…”

“…The Co 2p peak for Co 9 S 8 is reported to be observed around 781.5 eV in the literature. 40 The minor upfield shift (1.3 eV) of the peak in the current sample may possibly be attributed to the interaction of Co 9 S 8 with NiFeOOH in the heterostructure and oxide doping of the former. 41 The control sample (Ni−Co 9 S 8 ) synthesized in the absence of FeOOH displayed the Co 2p peak at 781.5 eV further supporting the above observation (Figure S2, SI).…”

Hexagonal Co9S8: Experimental and Mechanistic Study of Enhanced Electrocatalytic Hydrogen Evolution of a New Crystallographic Phase

“…The high‐resolution Co 2p spectra of Co 9 S 8 ‐fcc reveal four peaks of Co 2p 3/2 locate at 778.4, 780.9, 783.5, and 786.7 eV, and four peaks in Co 2p 1/2 are at 793.5, 796.9, 799.1, and 802.9 eV, respectively. The two‐couple peaks at 778.4 and 793.5 eV, 780.9 and 796.9 eV can be attributed to Co 3+ and Co 2+ in Co 9 S 8 ‐fcc, respectively, [ 29 ] which is very different from that for the CoS stoichiometry. [ 30,31 ] The couple peaks at 783.5 and 799.1 eV belongs to the oxidized Co species, [ 32 ] which may be due to the inevitable oxidation of Co elements when exposing to air.…”

Tailoring the d-band center of porous CoS2 nanospheres via low-electronegative Fe for weakened OH* adsorption and boosted oxygen evolution

“…[22][23][24] For the various strategies to develop OER catalysts, the regulation of electronic structure of catalysts can be the most effective method, thus optimizing the binding energy of intermediates, which can be determined by the d-band center of a transition metal site. [25][26][27][28][29][30][31][32][33] Recently, the introduction of low-electronegative metal atoms such as Fe (∼1.83), Mn (1.55), and Cr (1.66) has shown potential to promote OER performance due to the coupled d-orbital electronic configuration between CoS 2 and low-electronegative metal. 23 This will alter the antibonding filling state of the electrons in the CoS 2 active center, thereby optimizing the binding of the oxygen-containing intermediate to the CoS 2 surface.…”