N,S-codoped carbon encapsulated Co3S4@NiS/Cu2S hierarchical yolk-shell nanopolyhedron as bifunctional catalyst for efficient photovoltaics and alkaline hydrogen evolution

Abstract

The yolk-shell structure electrocatalysts formed by polymetallic sulfides hold great promise in a variety of energy conversion/storage fields. Herein, the nitrogen/sulfur codoped porous carbon encapsulated Co3S4@NiS/Cu2S nanopolyhedrons (NSC-Co3S4@NiS/Cu2S) with hierarchical yolk-shell structures were successfully designed and synthesized by a facile one-step high-temperature degradation of zeolite imidazolate framework-67 (ZIF-67) wrapped with metal-doped trithiocyanuric acid (TCA-M). Trithiocyanuric acid played a dual role, not only providing nitrogen, sulfur, and carbon sources, but also playing a role in the sulfurization of metal elements. It is worth noting that, due to the higher specific surface area, unique morphology, multi-element synergies, and more favorable chemical composition, the synthesized samples possessed outstanding bifunctional electrocatalytic performance for dye-sensitized solar cells (DSSCs) and hydrogen evolution reactions (HERs). Experimental results showed that NSC-Co3S4@NiS/Cu2S electrode has a high photoelectric conversion efficiency (9.57%) in DSSCs. In addition, NSC-Co3S4@NiS/Cu2S electrode also showed a lower initial overpotential (65.1 mV) and Tafel slope (49.7 mV dec-1) in the alkaline HERs test. The present approach has proposed a new synthetic idea of hierarchical yolk-shell metal sulfide in different new energy catalysis fields.