L-Cysteine assisted synthesis of Zn_(0.5)Cd_(0.5)S solid solution with different morphology, crystal structure and performance for H_2 evolution

摘要

L-cysteine was used as sulfur source for the preparation of Zn0.5Cd0.3S solid solutions with different morphology and crystal structure (wurtzite, zinc blende/wurtzite (Z/W) phase junctions, twin crystal). The morphology and crystal structure could be tuned by changing the reaction conditions, especially the solvents. In a mixed solvent of ethanolamine and water, nanorods with pure wurtzite structure were formed due to the capping effect of ethanolamine. If pure water was used as solvent, nanotetrahedrons with zinc blende/wurtzite (Z/W) phase junction structures can be prepared. In a mixed solvent of ethanediamine and water, nanospheres with high density of twin crystal structures were formed. The different crystal structures were revealed by electron dispersive spectrum (EDS), X-ray diffraction (XRD) experiments, transmission electron microscopy (TEM), and scan electron microscopy (SEM) for the nanorods, nanotetrahedrons, and nanospheres. Because of the existence of high density homojunction structures (Z/W junction and twin crystal), both nanotetrahedrons and nanospheres showed excellent photocatalytic activity for H-2 evolution from sacrificial reagent aqueous solutions. Especially, the nanospheres presented a H-2 production rate of about 0.8350 mmol h(-1) over 10 mg catalyst, corresponding to a QEs of 47.52%, in 0.75 M Na2S and 1.05 M Na2SO3 aqueous solutions under visible light (lambda = 420 nm) irradiation. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.