Constructing hierarchical cadmium sulfide via nitrogen-doped carbon dot-mediated interfacial engineering for enhanced hydrogen production

Abstract

A synthetic strategy was developed to fabricate a large surface-area, hierarchically structured and anti-photocorrosion CdS composite starting from CdCO₃ with the assistance of nitrogen-doped carbon dots (NCDs). Initially, NCDs were coated over the CdCO₃ surface. Once triggering the reaction, NCDs electrostatically enriched S^2- ions and meticulously regulated the interface between the newly formed CdS and CdCO₃ to facilitate mass transfer. This led to complete conversion to the composite NCDs/CdS, where CdS exhibited a hierarchical nanoflake-layer-particle architecture. Various characterization studies indicate that NCDs loaded on CdCO₃ dynamically promoted the formation of cubic-phase CdS. The unique morphology enlarged the specific surface area to 62.1 m² g^-1. Of the synthesized samples, NCDs/CdS-60 achieved a hydrogen production rate as high as 2.27 mmol g^-1 h^-1, which is almost 11-fold higher than that of CdS prepared without adding NCDs. Notably, the component of NCDs suppressed the hole-induced photocorrosion of CdS during the photocatalytic reaction and extended the catalyst's service life.