Revealing the pH-Universal Electrocatalytic Activity of Co-Doped RuO₂ toward the Water Oxidation Reaction

Abstract

Electrocatalytic water splitting has gained vast attention in recent decades for its role in catalyzing hydrogen production effectively as an alternative to fossil fuels. Moreover, the designing of highly efficient oxygen evolution reaction (OER) electrocatalysts across the universal pH conditions was more challengeable as in harsh anodic potentials, it questions the activity and stability of the concerned catalyst. Generally, geometrical engineering and electronic structural modulation of the catalyst can effectively boost the OER activity. Herein, a Co-doped RuO 2 nanorod material is developed and used as an OER electrocatalyst at different pH conditions. Co-RuO 2 exhibits a lower overpotential value of 238 mV in an alkaline environment (1 M KOH) with a Tafel slope value of 48 mV/dec. On the other hand, in acidic, neutral, and near-neutral environments, it required overpotentials of 328, 453, and 470 mV, respectively, to attain a 10 mA/cm 2 current density. It is observed that doping of Co into the RuO 2 could synergistically increase the active sites with the enhanced electrophilic nature of Ru 4+ to accelerate OER in all of the pH ranges. This study finds the applicability of earth-abundant-based metals like Co to be used in universal pH conditions with a simple doping technique. Further, it assured the stable nature in all pH electrolytes and needs to be further explored with other metals in the future.

Boosting of overall water splitting activity by regulating the electron distribution over the active sites of Ce doped NiCo–LDH and atomic level understanding of the catalyst by DFT study

“…The OER activity of NiCo–LDH/NF and Ce doped NiCo–LDH/NF was performed in a three electrode system using Pt as a counter electrode and Hg/HgO as reference electrode, respectively. 47 It is noticed that Ce doped NiCo–LDH/NF shows enhanced OER performance with low overpotential towards OER. 48 The OER activity was gradually increased when the NiCo–LDH/NF was doped with various concentrations of cerium.…”

Finding the True Catalyst for Water Oxidation at Low Overpotential in the Presence of a Metal Complex

“… Although 1 is decomposed to Ni (hydr)­oxide during OER, adding Fe to the formed Ni (hydr)­oxide results in a Ni/Fe (hydr)­oxide, which is among highly active OER catalysts (Table S2). Thus, among different strategies, − the decomposition of metal complexes is also promising. …”

Vanadium-Doped Nickel Cobalt Layered Double Hydroxide: A High-Performance Oxygen Evolution Reaction Electrocatalyst in Alkaline Medium

“…In this regard, various derivatives of transition metals like oxide, hydroxide, chalcogenide, pictinides, etc. have been proven to serve as a highly efficient water oxidation catalyst. ,− Recently, among all types of catalysts, catalysts comprising hydroxide ions, specially layer double hydroxides (LDHs) with unique layered structures, have gained an important consideration for OER under alkaline conditions …”