Search

CdSe@CdS@TiO2 microsheet array (MSA) ternary core–shell heterojunctions were prepared by successive electrodeposition of CdS and CdSe onto TiO2 microsheets using cyclic voltammetry. The photoelectrochemical performance of CdSe@CdS@TiO2 MSAs ternary core–shell heterojunctions is significantly improved. This structure not only greatly enhances the utilization efficiency of visible light but also greatly extends the spatial separation of photoinduced charge. This is because CdSe@CdS@TiO2 MSAs ternary core–shell heterojunctions have an inherent cascade energy band structure and a high-quality contact between each other at the interface. After annealing, CdSe@CdS@TiO2 MSAs ternary core–shell heterojunctions show a further improved photoelectrochemical performance because the formation of ternary compound CdS1−xSex enhances the quality of the contact interface between CdSe and CdS layers and consequently increases the transportation efficiency of photoinduced charges and injection efficiency of photoinduced electrons to the TiO2 layer. The maximum photocurrent density of 3.5 mA/cm2 was observed in the CdSe@CdS@TiO2 MSAs ternary core–shell heterojunctions after annealing at 350 °C, which is 9.46, 3.18 and 2 times higher than that observed in CdS@TiO2 MSA, CdSe@TiO2 MSA, and as-prepared CdSe@CdS@TiO2 MSA photoelectrodes, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Smooth and uniform Cu2O thin films were prepared by electrodeposition on Sn-doped indium oxide substrates (ITO) in Cu(Ac)2 electrolytes with thiourea addition. The influence of deposition potential and thiourea concentration on the formation of these thin films was investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The results show that smooth and uniform Cu2O thin films were achieved by electrodeposition under the potential of −0.1V (vs. SCE) with 0.5mM thiourea, which exhibited obvious absorbance and photocurrent response in visible light range. In addition, as the concentration of thiourea increased, the density of Cu2O thin films decreased. Based on this, the thiourea assisted growth process was proposed as a plausible mechanism for the formation of smooth and uniform Cu2O thin films. [Copyright &y& Elsevier]

Abstract: Coaxial heterostructures based on n-type TiO2 nanotubes (TNTs) arrays enclosed with p-type Cu2O nanoparticles were prepared through a combination of anodic oxidation and subsequent electrodeposition. Cu2O nanoparticles were electrodeposited into the inter-tubular space of TNTs to form the coaxial core–shell TNTs@Cu2O heterostructures. The Cu2O nanoparticles were preferentially deposited on the ribs of TNTs arrays, and the amount of thiourea added during electrodeposition of Cu2O played an important role in formation of coaxial core–shell TNTs@Cu2O heterostructures. The heterostructures exhibited excellent photoelectrochemical performance under visible light. Such heterostructures would serve as a promising candidate for solar energy conversion. [Copyright &y& Elsevier]

The different configurations of CdSe nanoparticles, Au nanocrystals and TiO 2 nanotube arrays play an important role in the photoelectrochemical behavior and photoelectrocatalytic hydrogen production of this heterogeneous photoelectrode system. It is discovered that the photoelectrocatalytic hydrogen production of the TiO 2 –CdSe–Au photoelectrode (1.724 mmol g−1 h−1) is about 4 times that of the TiO 2 –Au–CdSe photoelectrode (0.430 mmol g−1 h−1) under visible light irradiation. From the comprehensive investigation of their photoelectrochemical behaviors, it is illustrated that the interfacial electrical field has distinct effects on the separation and transportation of photogenerated carriers in these heterostructure photoelectrodes. The directions of the interfacial electrical fields formed at TiO 2 –Au and Au–CdSe interfaces are opposite in the TiO 2 –Au–CdSe photoelectrode, which hinders the separation of photogenerated electron-hole pairs and subsequent transportation of photogenerated carriers. On the contrary, the directions of the interfacial electrical fields formed at TiO 2 –CdSe and CdSe–Au interfaces are identical in the TiO 2 –CdSe–Au photoelectrode, which promotes the separation of photogenerated excitons and subsequently enhances their transportation for enlarged photocurrent density. The results of photoelectrocatalytic hydrogen production also confirm our assumption. • The configurations have crucial effect on photoelectrochemical behavior. • Interfacial electrical field has effects on transportation of photoinduced carriers. • Electrical field at interfaces of TiO 2 –CdSe and CdSe–Au have identical directions. • Electrical field at interfaces of TiO 2 –Au and Au–CdSe have opposite directions. [ABSTRACT FROM AUTHOR]