Hierarchical Bi2S3@CoS2/MoS2 core-shelled microspheres as bifunctional electrode catalysts for efficient triiodide reduction and alkaline hydrogen evolution reactions

The core-shelled structural electrocatalysts composed of multiple transition metal sulfides are of broad promise in diverse power conversion and storage techniques. Herein, we have employed a plausible strategy to synthesize a series of porous composite electrocatalytic materials with hierarchical architecture based on metal-organic framework (MOF) derivatives (Bi2S3 @CoS2/MoS2, CoS2/MoS2, and Bi2S3 @MoS2). Remarkably, by virtue of the huge specific surface area, unique surface appearance, and the synergistic effect of multi-metals, the catalyst exhibits excellent electrocatalytic performance as a bifunctional catalyst in dye-sensitized solar cells (DSSCs) and hydrogen evolution reactions (HERs). Herein, the quaternary Bi2S3 @CoS2/MoS2 microspheres exhibit remarkable merits in facilitating the regeneration of iodine redox pairs in DSSCs as well as improving hydrogen evolution activity concerning CoS2/MoS2 and Bi2S3 @MoS2 microspheres. Particularly, the DSSCs with Bi2S3 @CoS2/MoS2-based counter electrode performed superior power conversion efficiency (PCE) of 9.43 %, outperforming that of Pt (7.87 %). Besides, a low onset overpotential of 29.5 mV, small Tafel slope of 56.2 mV dec(-1), and low overpotential of 94.7 mV at the current density of 10 mA cm(-2) were delivered for Bi2S3 @CoS2/MoS2 as HERs electrocatalyst under alkaline environment. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

Porous composite electrocatalytic materials based on metal-organic framework (MOF) derivatives show excellent performance in dye-sensitized solar cells (DSSCs) and hydrogen evolution reactions (HERs) due to their huge specific surface area and unique surface appearance.