A Multi‐Active Site Subnano Heterostructures Catalyst Grown In situ POM and Fe0.2Ni0.8Co2O4 onto Nickel Foam Toward Efficient Electrocatalytic Overall Water Splitting

• Published in: Advanced functional materials Vol. 34; no. 49
• Main Authors: Cui, Li‐ping, Wang, Yu‐wen, Yu, Kai, Ma, Ya‐jie, Zhou, Bai‐bin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 02.12.2024
• Subjects: Catalysts; Density functional theory; Electrocatalysts; Electron distribution; Electron transfer; Heterojunctions; Heterostructures; Hydrothermal reactions; Metal foams; Nanoclusters; nanometer heterostructures; Nickel; overall water splitting; polymetallic oxide nanoflowers; polyoxometalates; Polyoxometallates; Reaction kinetics; Synergistic effect; Water chemistry; Water splitting
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202408968

Designing efficient, durable, and cheap bifunctional electrocatalysts is a challenging goal in water splitting. Herein, trivanadium‐substituted Keggin‐type polyoxometalate H6PV3Mo9O40 (POM) and Fe0.2Ni0.8Co2O4 (FNCO) are in situ grown onto nickel foam (NF) yielding a self‐supporting nanoflower‐like heterojunction via convenient hydrothermal reaction. The POM‐Fe0.2Ni0.8Co2O4/NF as HER and OER electrocatalyst, displays low overpotential (89 and 259 mV) and high electrode stability at 10 mA cm−2. POM‐FNCO/NF as the cathode and anode requires a lower voltage (1.58 V) to provide 10 mA cm−2 for overall water splitting (OWS), which is better than that of commercial catalysts. The electronic sponge characteristics of POM provide more active sites and fast reaction kinetics for HER and OER. The synergy of POM and FNCO optimizes the electron distribution at the interface and enhances the intrinsic activity of HER/OER. Density Functional Theory (DFT) calculations show that water molecules preferentially bind to Co sites on POM‐FNCO. Additionally, POM has proton‐coupled electron transfer properties and its modified FNCO exhibits thermodynamic advantages. The synergistic effect of these two factors enables the efficient overall water splitting of POM‐FNCO. This study offers a novel pathway for the construction of self‐supporting efficient catalysts by in situ growth of POM nanoclusters and spinel oxide sub‐nanometer heterojunctions on NF. POM and Fe0.2Ni0.8Co2O4 is grown in situ on nickel foam yielding multi‐active site heterostructures, which display excellent electrocatalytic activity for total water splitting ascribing to a good synergistic effect of POM nanoclusters and spinel oxide subnano flowers.