Electrochemical behavior of Co3C carbide

Abstract

The electrochemical properties of the Co 3 C carbide have been studied. In contrast to metallic cobalt, its carbide is characterized by higher electrocatalytic activity in the hydrogen evolution reaction and low rate of anodic oxidation in acidic sulfate solutions. The oxidation in borate solutions (pH=6.3-9.0) results in the formation of oxide films different in phase composition. In the case of metallic cobalt, a passive film consisting of CoO and Co(OH) 2 forms, while the cobalt carbide oxidation results in the formation of the Co 3 O 4 film. The oxidation of cobalt carbide is an irreversible process accompanied by the accumulation of carbon on the surface.

Tailor-made preparation of Co–C, Co–B, and Co catalytic thin films using magnetron sputtering: insights into structure–composition and activation effects for catalyzed NaBH4hydrolysis

“…4 shows the XPS surface analysis performed on selected, representative, fresh samples deposited on the PTFE membranes (Co 50 -hp, Co 50 B 100 and Co 50 C 100 ). The Co (2p) binding energies at 777.8 (Co 2p 3/2 ) and 792.9 eV (Co 2p 1/2 ) are consistent with those of metallic cobalt, 5,23,33,34 cobalt borides (Co x B) 35,36 or cobalt carbides, 37 which cannot be clearly differentiated using XPS analysis. Oxidized species are also detected on the surface, corresponding to Co (2p) peaks at higher binding energies of 780.9 (Co 2p 3/2 ) and 796.4 eV (Co 2p 1/2 ).…”

Metal–Organic Framework Derived Narrow Bandgap Cobalt Carbide Sensitized Titanium Dioxide Nanocage for Superior Photo‐Electrochemical Water Oxidation Performance

“…For O 1s XPS spectrum, the two different chemical states at 531.1 and 530.4 eV can be attributed to the TiO and CoO bonding (Figure S9c, Supporting Information). From the Co 2p plots, XPS peaks of Co 2p 1/2 and Co 2p 3/2 centred at 794.3 eV, 778.2 eV and 797.1 eV, 782.5 eV can be detected, which are ascribed to the CoC and CoO bonding . The C 1s XPS spectrum in Figure S9e (Supporting Information) exhibits two chemical bonding states at 284.6 and 282.9 eV, which can be attributed to the carbon‐based containment and CoC bonding …”

Transformation of a Cobalt Carbide (Co3C) Oxygen Evolution Precatalyst

“…OER electrocatalytic performance of the Co 3 C precatalyst was evaluated using rotating disk electrode (RDE) measurements, as displayed in 26 One can readily see that Co 3 C and CoO have similar overpotentials (455 mV) on the glassy carbon (GC) substrates at 10 mA•cm −2 geo , however Co 3 C showed a lower overpotential (511 mV) than CoO (566 mV) at a higher current density (40 mA•cm −2 geo ). To separate surface area effects from the intrinsic activity, we analyzed the ECSA (details in Figure S3) and computed an ECSA normalized current density (mA• cm −2 ECSA ).…”

“…We collected a second sweep of a linear sweep voltammetry (LSV) curve for analysis of the OER (in the range of 1.0–1.9 V) because the oxidation of the Co 3 C particles occurred primarily during the first sweep (see the Figure a inset). The inset shows there are two distinct peaks in the anodic region; the peak in the vicinity of 0.3 V is related to the oxidation of carbide (Co 3 C → Co 3 O 4 ), and Co 3 O 4 is oxidized to CoOOH and/or Co 2 O 3 at ∼1.2 V …”

“…A Shirley background was subtracted from the spectrum before deconvolution. Blue solid line, Co carbide; green line, Co oxide; pink and cyan lines, Co (oxy)­hydroxide satellite peaks. , …”