Sulfur-doped cobalt oxide nanowires as efficient electrocatalysts for iodine reduction reaction

Abstract

Sulfur-doped cobalt oxide (S-Co 3 O 4) crystals exhibit excellent catalytic activities towards multiple useful reactions, however, the impact of the structural properties on the resultant catalytic activities has been overlooked in the past. We demonstrate a facile vaporphase hydrothermal (VPH) doping approach to effectively create electrocatalytically active surface sulfur species on the chemical bath deposited polycrystalline Co 3 O 4 nanowires for iodine reduction reaction (IRR). The dye-sensitized solar cells (DSSCs) equipped with the S-Co 3 O 4 nanowire film as the counter electrode (CE) achieve a best energy conversion efficiency of 6.78%, which is comparable to those of DSSCs with commercial Pt CE (7.36%). The impact of film structure, VPH temperature and VPH duration on the resultant structures as well as the electrocatalytic activities has been comprehensively studied. More importantly, our results manifest a close correlation between the surface sulfur dopant level and the key electrocatalytic activity indicators. The VPH approach could be further extended to the fabrication of low-cost, high-performance nanomaterials for energy conversion applications.

Improved Redox Reaction of Lithium Polysulfides on the Interfacial Boundary of Polar CoC2O4 as a Polysulfide Catenator for a High‐Capacity Lithium‐Sulfur Battery

“…In contrast to the Co 2p spectrum of pristine cobalt oxalate, wherein the dominant Co 2+ peak is located at 781.6 eV, new peaks appear at 778.3 eV for Co 2p 3/2 and 793.2 eV for Co 2p 1/2 . The additional peak observed at lower binding energy than that of the Co 2+ peak correlates with the results from the previous XPS studies of cobalt sulfides, cobalt phosphide, CoOOH, and sulfur‐doped cobalt compounds, indicating strong Co−S interaction [37–41] . Chemical bonds between the cobalt and sulfur can be identified in the S 2p spectra.…”

In Situ Reconstruction to Surface Sulfide Adsorbed Metal Scaffold for Enhanced Electrocatalytic Hydrogen Evolution Activity

“…X‐ray photoelectron spectroscopy (XPS) measurements (Figure S7, Supporting Information) imply the successful doping of S 2− anion, which agrees well with the previous reports. [ 12,13 ] Furthermore, when comparing to the Co 2p XPS spectra of Co 3 O 4 /CC, obvious shifts of Co 2p 3/2 peaks towards the lower binding energies can be observed for S‐Co 3 O 4 /CC (Figure 1e). Meanwhile, S‐Co 3 O 4 /CC has an insignificant contribution of lattice O 2− according to the O 1s XPS spectra (Figure 1e), demonstrating the presence of plentiful anion vacancies.…”

Review on Low‐Cost Counter Electrode Materials for Dye‐Sensitized Solar Cells: Effective Strategy to Improve Photovoltaic Performance

“…Later, in order to manifest the relationship between the surface sulfur dopant level and catalytic activity, his group synthesized S-doped Co 3 O 4 nanowires. [81] Meanwhile, the other influential factors on catalytic activity were also investigated. The above strategy can unlock the catalytic potential of metal oxide for I 3 − reduction in DSSCs.…”