Delafossite CuMnO₂ as an Efficient Bifunctional Oxygen and Hydrogen Evolution Reaction Electrocatalyst for Water Splitting

Abstract

Delafossite CuMnO 2 powder composed of earth-abundant elements was synthesized by a sol-gel process and thoroughly characterized by powder X-ray diffraction, SEM, XPS, FT-IR, and Raman spectroscopy. More importantly, their electrocatalytic performances for oxygen and hydrogen evolution reactions (OER and HER) have been fully investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry with a rotating electrode in 1 M KOH electrolyte versus Ag/AgCl. Based on the measurements from these CuMnO 2 -based working electrodes, the specific capacitance, total charge, most accessible charge, electrochemically active surface area, and roughness factor were calculated for the first time. Their stability was also studied for cost-effective and active electrode material. Furthermore, by comparing measurements at 1600 rpm and no rotation of the electrodes in alkaline media, the delafossite CuMnO 2 synthesized in this work showed current densities of 12.3 mA/cm 2 at 1600 rpm and 11.9 mA/cm 2 at no rotation for OER and 6.9 mA/cm 2 and 6.3 mA/cm 2 for HER. Overall, our study demonstrated that delafossite CuMnO 2 possesses effective bifunctional OER and HER activities.

Molten Salt Synthesized Submicron Perovskite La1–xSrxCoO3 Particles as Efficient Electrocatalyst for Water Electrolysis

“…Calculation of q * is determined following Eq. 2 as reported by Audichon et al (2014), Mohan and Mao (2018), Mao et al (2019).…”

“…Three-electrode electrochemical cell configuration was used (Mohan and Mao, 2018;Mao et al, 2019). The working electrode was the catalyst-coated glassy carbon electrode with an area of 0.5024 cm 2 ; a platinum wire was used as the counter electrode and the Ag/AgCl electrode as the reference electrode.…”

“…The CV curves of all LSCO catalysts modified as working electrodes ( Figure 3A) exhibits a characteristic shape with the presence of the anodic and cathodic peak at a potential range of 0.4-1 V vs reversible hydrogen electrode (RHE), indicating a nonreversible reaction (Mohan and Mao, 2018;Mao et al, 2019). Also, the LSCO30% sample showed the highest current density and the LSCO0% showed the lowest current density among the five samples.…”

Piezoelectric properties of PVDF‐conjugated polymer nanofibers

“…Charge storage of our developed systems was calculated using Equation reported by Audichon et al 31 below where v is the scan rate, m is the mass in milligrams of the catalyst deposited on the working electrode, s is the surface area of the working electrode, E 1 and E 2 are limits of potential of the integration curves, and is the integration of the cyclic voltammogram curve. The voltametric charge (q*) was obtained from the cyclic voltammogram 29,30 Figures 3(a) to (e) show the cyclic voltammograms for the PVDF/CP nanofiber systems (PVDF/PANI, PVDF/PANA, PVDF/PIN, PVDF/PPY, and PVDF/PCZ, respectively) and were carried out using 0.5 M H 2 SO 4 as electrolyte at a scan rate of 20 mV/sec.…”

Synthesis of N-rGO-MWCNT/CuCrO2 Catalyst for the Bifunctional Application of Hydrogen Evolution Reaction and Electrochemical Detection of Bisphenol-A

“…Therefore, for renewable energy and the global economy, there is an immediate need to design a more successful and efficient electrocatalyst from earth-abundant materials for water electrolysis [15,16]. Presently, delafossite metal oxides have further consideration for applications due to the higher electrocatalytic activity and well metal-oxygen bond interaction [17,18].…”