A CoV₂O₄ precatalyst for the oxygen evolution reaction: highlighting the importance of postmortem electrocatalyst characterization

Abstract

Postmortem analysis of a CoV2O4 catalyst for oxygen evolution reveals the active species is likely a vanadium-free amorphous cobalt oxide.

Electrochemical Oxidation of Primary Alcohols Using a Co2NiO4 Catalyst: Effects of Alcohol Identity and Electrochemical Bias on Product Distribution

“…It is also important to confirm whether the catalyst structure and composition are maintained after electrochemical AOR experiments. ,− To this end, we conducted postmortem materials characterization on the Co 2 NiO 4 catalysts after subjecting electrocatalytic films to rotating disk electrode controlled potential electrolysis (RDE-CPE) measurements under catalytically relevant conditions: mounted into a rotating disk electrode (RDE) assembly at 1600 rpm rotation rate and held at 1.55 V vs RHE in 0.1 M NaOH electrolyte with 0.10 M n -BuOH. A representative RDE-CPE experiment under these conditions is shown in Figure S6 and shows an ∼25% decrease in activity over the 2 h electrolysis consistent with the activity losses seen for various analogously prepared catalyst films studied for the OER. ,, …”

“…For postmortem PXRD and ICP-MS measurements, particles were collected from the electrode surface using a previously reported procedure . Briefly, each modified working electrode was removed from the electrolyte and RDE sheath after the unsealed CPE measurements and submerged in i -PrOH in a centrifuge tube.…”

“…Co 2 NiO 4 was deposited onto the polished glassy carbon surfaces via dropcasting of a catalyst ink suspension as previously described. , Briefly, catalyst ink suspensions were prepared by adding 80 mg of the Co 2 NiO 4 powder into a solution of 3.8 mL of H 2 O, 1 mL of i -PrOH, and 40 μL of 5 wt % Nafion 117 solution added in that order. Immediately prior to dropcasting, the suspension was sonicated for 30 min to disperse the Co 2 NiO 4 powder.…”

“…For postmortem PXRD and ICP-MS measurements, particles were collected from the electrode surface using a previously reported procedure. 63 Briefly, each modified working electrode was removed from the electrolyte and RDE sheath after the unsealed CPE measurements and submerged in i-PrOH in a centrifuge tube. The centrifuge tube containing the modified working electrodes in i-PrOH was then sonicated for 30 min to dissolve the Nafion binder and release the particles into the i-PrOH.…”

Bias-induced surface reconstruction of a MOF-derived bimetallic (Co & V) oxide as an electrocatalyst for water oxidation

“…This finding not only revealed the catalytic activity of CoV-MOF-derived annealed materials but also showed that it is necessary to conduct postmortem analysis of the catalyst after electrocatalysis to know the fate of the starting material. 36–38…”