Xin-Zheng Yue,Chuan-Qi Li,Zhong-Yi Liu,Sha-Sha Yi,De-Liang Chen,Feng Wang,Shuai-Hui Li
The constructing of functional materials with well-defined nanostructure , showing efficient charge separation and transportation properties, has been intensively and in depth investigated to fabricate catalysts for H 2 generation from solar-driven water reduction. Here we demonstrate that loading W 2 C@C structure in which each W 2 C nanoparticle (NP) is wrapped by carbon shell on surface of hollow TiO 2 microspheres (HTMs) can enhance the separation of photogenerated electron-hole pairs by building an internal electric field in W 2 C@C/HTMs composite structure and act as the reaction active sites for water reduction. As expected, the optimized W 2 C@C/HTMs construction exhibits the highest photocatalytic H 2 generation rate of 6.91 mmol h −1 g −1 under simulated solar light illumination, over 20 times larger than that of bare HTMs. The underlying mechanism has been investigated from the perspective of photochemistry and photophysics based on a series of characterization techniques, which suggests that W 2 C@C can effectively steer the charge kinetics, maximizing the charge carriers’ separation.
We report a novel nanocomposite of hollow TiO2 microspheres and plasma polyacrylic acid (TiO2@PPAA) modified with rhodamine B (TiO2@PPAA-RhB). This nanocomposite was further used as an electrochemical sensor for the ultra-sensitive and selective detection of Cu2+ in water. A gold electrode was modified with hollow TiO2 nanospheres, followed by the closely bonded layer of PPAA via plasma polymerization. Subsequently, the carboxyl groups of TiO2@PPAA nanocomposites were activated to ester groups by N-hydroxysuccinimide/1-ethyl-3-(3-dimethylaminoprolyl) carbodiimide hydrochloride. The resultant activated ester groups reacted with the amino groups on rhodamine to form the amide groups, leading to the modification of TiO2@PPAA nanocomposites with rhodamine. Considering the synergistic effect of strong electrostatic interaction between the carboxyl groups of PPAA and Cu2+, the direct adsorption of Cu2+ on the TiO2 surface, and the coordination chemistry formed between Cu2+ and rhodamine, the developed electrochemical biosensor exhibited high sensitivity of Cu2+ detection, with a detection limit of 0.404 pM within the range of 0.001–10 nM of Cu2+. Therefore, the fabricated electrochemical sensor based on TiO2@PPAA-RhB can be obtained via plasma polymerization and represents a highly promising tool for use in environmental monitoring.
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