Interfacially Coupled and Synergistic Effect of Ag/Co3O4-C Nanocomposites for Enhanced Oxygen Reduction (ORR) and Evolution (OER) Reaction
Qaseem A. Chen F. Shabbir A. Saleem M. Koh J.H. Khan M.Z. Shakir I. Masood M.T. Kishibayev K.
9 March 2026John Wiley and Sons Inc
Advanced Science
2026#13Issue 14
Overpotentials associated with the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remain key challenges hindering the practical deployment of advanced electrochemical energy conversion technologies such as alkaline fuel cells. While Pt/C demonstrates excellent ORR activity, its sluggish OER kinetics and poor durability in alkaline environments significantly limit its applicability. Herein, we report the design of an Ag/ Co3O4-C nanocomposite, synthesized via a two-step approach involving hydrothermal growth of ultrafine Co3O4 nanoparticles having a particle size of 5 nm, followed by uniform deposition of Ag nanoparticles having a particle size of 20–30 nm. TEM/EDS shows Co3O4 nanoparticles (∼5 nm) uniformly anchored on the carbon matrix with finely dispersed Ag (∼28 nm), producing a homogeneous Ag– Co3O4 distribution. XPS indicates no substantial charge transfer, with performance arising from ensemble/heterointerface effects. The resulting hybrid exhibits superior ORR activity with an onset potential of 0.10 V vs. Hg/HgO and a half-wave potential of –0.186 V vs. Hg/HgO, while simultaneously delivering enhanced OER activity by reaching 10 mA cm−2 at a substantially lower overpotential compared to Ag/C and Co3O4-C. In addition, when integrated into Zn–air batteries, the Ag/ Co3O4-C cathode demonstrates a high discharge capacity of 730 mAh g−1, a peak power density of 67 mW cm−2, and stable cycling for 200 cycles, validating its strong bifunctional electrocatalytic performance. The synergistic coupling of Ag and Co3O4 nanoparticles, anchored on a conductive carbon framework, enables efficient interfacial charge transfer and optimizes the adsorption of oxygenated intermediates, thereby accelerating reaction kinetics in alkaline media. Owing to these complementary features, the Ag/Co3O4-C catalyst demonstrates excellent bifunctional activity, highlighting its promise for next-generation oxygen electrocatalysis.
bifunctional catalyst , energy , nanocomposite , oxygen evolution reaction , oxygen reduction reaction
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Centres of Excellence in Science & Applied Technologies, CESAT, Islamabad, Pakistan
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xian, China
School of Chemical and Materials Engineering (SCME), National University of Sciences and, Technology (NUST), Islamabad, Pakistan
School of Electrical and Electronic Engineering, Chung-Ang University, Seoul, South Korea
Pak-Austria Fach Hochschule: Institute of Applied Sciences, Department of Materials Science and Engineering, KPK, Haripur, Pakistan
Department of Physics, Faculty of Science, Islamic University of Madinah, Madinah, Saudi Arabia
Center of Physical-Chemical Methods of Research and Analysis, Al-Farabi Kazakh National University, 96 A, Tole bi Street, Almaty, 050012, Kazakhstan
Centres of Excellence in Science & Applied Technologies
State Key Laboratory of Solidification Processing
School of Chemical and Materials Engineering (SCME)
School of Electrical and Electronic Engineering
Pak-Austria Fach Hochschule: Institute of Applied Sciences
Department of Physics
Center of Physical-Chemical Methods of Research and Analysis
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