CdS-loaded flexible carbon nanofiber mats as a platform for solar hydrogen production

Abstract

Photocatalysis-based solar hydrogen (H2) has garnered attention as a renewable energy carrier, yet the technology is still immature. For practical operation of photocatalytic H2 production, we fabricated a novel heterojunction of CdS-loaded flexible carbon nanofiber (CNF) mats. CNF mats were prepared by electrospinning and carbonization. CdS nanoparticles were deposited in alcohol and water solutions by the successive ionic layer adsorption and reaction (SILAR) method. The former solution was found to be more effective in uniformly dispersing CdS particles in the CNF mats. When pristine CNF mats were treated with acid (hereafter CdS/a-CNF), the degree of CdS particle distribution was further enhanced. Moreover, H2 production was improved by a factor of 3 in an aqueous solution of Na2S (0.1 M) and Na2SO3 (0.1 M) under visible light (λ > 420 nm). Heat-treatment of CdS/a-CNF mats at 400 °C dramatically increased H2 production by 3.6 times due to the improved crystallinity of the CdS particles. In this heterojunction, the CNF mats have three roles: They work as a multi-scalable support for CdS particles, enhance photogenerated charge transfers, and catalyze H2 evolution.