Biomass as a Template Leads to CdS@Carbon Aerogels for Efficient Photocatalytic Hydrogen Evolution and Stable Photoelectrochemical Cells

Abstract

A facile strategy to fabricate cadmium sulfide@carbon aerogels (CdS@CAs) has been demonstrated based on the “double-helix” structure of Cd-carrageenan hydrogel. The carrageenan and the extract of seaweed biomass were crucial components for the synthesis of CdS@CAs, since they provide a sustainable template and also serve as the carbon and sulfur sources. The obtained CdS@CAs not only exhibited enhanced photocatalytic hydrogen evolution reaction performance but also showed high photoelectrochemical activity and super photostability. In particular, the sample with the optimum carbon content achieved the highest HER rate of 113.5 μmol h–1 and 100 μA cm–2 of photocurrent under visible light. Moreover, it retained excellent stability after 4000 s of operation under illumination. The improved performance of CdS@CAs was ascribed to the unique three-dimentional (3D) porous structure of CAs as the support. To be specific, the interconnected macropores and large mesopores of CAs were found to be beneficial for the fast mass transfer of contaminants and easy accessibility to CdS nanoparticles. In addition, the high electrical conductivity of CAs can efficiently separate and transfer the photogenerated charges and, thus, enhance the photocatalytic performance and stability. This strategy opens up new opportunities in the use of seaweed biomass to fabricate high-performance photocatalysts.