Morphological regulation of sulfur–vacancy–rich CdS for tunable CO2 photoreduction under visible irradiation

Abstract

In this work, morphological control on a series of sulfur–vacancy–rich CdS photocatalysts has been achieved toward the optimization of their performances in CO2 photoreduction. Results show that the sulfur–vacancy–rich CdS nano–platelets (p–CdS–Vs) exhibits the highest CO2 photoreduction activity with a CO yield of 4058.5 μmol h–1 g–1, which is 10 and 6 times those of the sulfur–vacancy–rich CdS nanowires (w–CdS–Vs, 372.8 μmol h–1 g–1) and nanorods (r–CdS–Vs, 638.7 μmol h–1 g–1), respectively, amongst the highest numbers for CdS–based photocatalysts reported hitherto. The superior CO2 photoreduction performance of p–CdS–Vs is attributable to its high efficiency of electron transport and suppressed recombination of photogenerated charge carriers. Mechanistic study indicates a critical role of surface sulfur vacancies that provide a microenvironment to trap unpaired electrons for the separation of photogenerated carriers so that photocatalytic efficiency of CO2–to–CO reduction is largely improved in this current system.