Transition-Metal-Substituted Cobalt Carbonate Hydroxide Nanostructures as Electrocatalysts in Alkaline Oxygen Evolution Reaction

Abstract

Tuning of morphology and the electronic structure through substitution in the crystal lattice can enhance the performance of electrocatalysts. In view of this, the present work is focused on one-step hydrothermal fabrication of graphite paper (GP)supported cobalt carbonate hydroxide (Co 2 (CO 3 )(OH) 2 /GP) nanostructures and its nickel-and manganese-substituted products, Co 1.9 Ni 0.1 (CO 3 )(OH) 2 /GP and Co 0.95 Mn 0.05 CO 3 /GP, respectively. This is followed by the investigation of their crystal structure, morphology, and electrocatalytic oxygen evolution activity. Our findings showed modification of the electronic structure in substituted cobalt carbonate hydroxides. In addition, specific and electrochemically active surface areas were also enhanced in Co 1.9 Ni 0.1 (CO 3 )(OH) 2 /GP and Co 0.95 Mn 0.05 CO 3 /GP compared to pure Co 2 (CO 3 )(OH) 2 /GP. It was noted that Ni-and Mn-substituted Co 2 (CO 3 )(OH) 2 exhibited dramatically enhanced oxygen evolution reaction (OER) performance in 1.0 M KOH. In addition, the mechanism of the OER was explored experimentally to reveal the origin of their enhanced electrocatalytic activity. Our findings also established the relatively superior performance of Co 1.9 Ni 0.1 (CO 3 )(OH) 2 /GP and Co 0.95 Mn 0.05 CO 3 /GP compared to the commercial RuO 2 electrocatalyst for oxygen evolution in alkaline media. It was also inferred that Co 1.9 Ni 0.1 (CO 3 )(OH) 2 /GP exhibited the best performance as indicated by the lowest overpotential (∼ 266 mV) in achieving 10 mA cm −2 current density, a small Tafel slope (∼ 44.8 mV dec −1 ), quite low chargetransfer resistance (∼ 0.72 Ω), and excellent durability. Thus, Ni-substituted Co 2 (CO 3 )(OH) 2 nanostructures could be employed as promising, efficient, and durable electrocatalysts for the OER in alkaline media.

Electrooxidation of Alcohols on Mixed Copper–Cobalt Hydroxycarbonates in Alkaline Solution

“…However, by performing three CVs in the OER region, changes in the electrocatalytic OER activity were observed especially for the Co‐rich samples for which an increased electrocatalytic was recorded. This can be attributed to an increased CoOOH‐formation at higher potentials, whose oxidation was reported to be important for the OER activity on Ni‐ and Mn‐substituted Co hydroxycarbonate catalysts [48] …”

“…This can be attributed to an increased CoOOHformation at higher potentials, whose oxidation was reported to be important for the OER activity on Ni-and Mn-substituted Co hydroxycarbonate catalysts. [48] The electrocatalytic activity of the Cu-Co hydroxycarbonates in the electrooxidation of alcohols was evaluated using a similar protocol as for the OER, with the difference that 0.1 M of the specific alcohol (ethanol, ethylene glycol, or glycerol) was added to the 1 M KOH solution. The recorded CVs (Figure 7a, c and e, cf.…”

“…[46,47] So far, these hydroxycarbonates have been explored in electrocatalysis only in their pure Co or Ni-and Mn-substituted form for OER, HER and oxygen reduction reaction. [48][49][50][51][52][53] To the best of our knowledge, there has not been a comprehensive study yet on the systematic variation of different transition metal cations in malachite-type catalysts for the AOR.…”

Mixed Transition Metal Carbonate Hydroxide‐Based Nanostructured Electrocatalysts for Alkaline Oxygen Evolution: Status and Perspectives

“…Figure displays a pie chart of the available reports on the electrocatalytic alkaline OER activities of transition metal carbonate hydroxides to date. [ 55–57,59,60,67–99 ] The present review commences with a general discussion of the electrochemical pathways and mechanism of OER in alkaline media. Subsequently, all the activity‐determining parameters in the OER and comprehensive studies on first‐row transition‐metal‐based multimetallic MTMCHs as OER electrocatalysts are discussed.…”

Facile preparation of Cu–Fe oxide nanoplates for ammonia borane decomposition and tandem nitroarene hydrogenation

“…The increased human exploitation of fossil fuels has caused serious environmental problems and depletion of resources, which makes it necessary to develop new types of green and sustainable alternative energy sources. 1,2 Hydrogen has attracted great attention and is likely to become the main source of energy in the future. 3,4 As chemical hydrogen storage materials, B-N compounds generally have high hydrogen densities.…”