Decoration of green synthesized S, N-GQDs and CoFe2O4 on halloysite nanoclay as natural substrate for electrochemical hydrogen storage application

Abstract

Halloysite nanotubes (HNTs) with high active sites are used as natural layered mineral supports. Sulfur- and nitrogen-co doped graphene quantum dots (S, N-GQDs) as conductive additive and CoFe2O4 as the electrocatalyst was decorated on a HNT support to design an effective and environmentally friendly active material. Herein, an eco-friendly CoFe2O4/S, N-GQDs/HNTs nanocomposite is fabricated via a green hydrothermal method to equip developed hydrogen storage sites and to allow for quick charge transportation for hydrogen storage utilization. The hydrogen storage capacity of pure HNTs was 300 mAhg−1 at a current density of 1 mA after 20 cycles, while that of S, N-GQD-coated HNTs (S, N-GQDs/HNTs) was 466 mAhg−1 under identical conditions. It was also conceivable to increase the hydrogen sorption ability through the spillover procedure by interlinking CoFe2O4 in the halloysite nanoclay. The hydrogen storage capacity of the CoFe2O4/HNTs was 450 mAhg−1, while that of the representative designed nanocomposites of CoFe2O4/S, N-GQDs/HNTs was 600 mAhg−1. The halloysite nano clay and treated halloysite show potential as electrode materials for electrochemical energy storage in alkaline media; in particular, ternary CoFe2O4/S, N-GQD/HNT nanocomposites prove developed hydrogen sorption performance in terms of presence of conductive additive, physisorption, and spillover mechanisms.