Dai-Song Chen,Wen-Bei Yu,Zhao Deng,Jing Liu,Jun Jin,Yu Li,Min Wu,Li-Hua Chen,Bao-Lian Su
Hollow Cu2O microspheres (0.7 to 4 μm in diameter) with two active {111} and {110} facets have been prepared in water/ethylene glycol (H2O/EG) solution via a fast hydrothermal route in only 1 h. Due to the dangling “Cu” atoms in the highly active {111} and {110} facets, the microspheres demonstrate preferential selective adsorption and photodegradation for negatively charged methyl orange (MO), comparing to cationic rhodamine B (RhB) and neutral phenol. The 0.7 μm hollow Cu2O microspheres show the best adsorption capacity and photodegradation performance for MO removal: 49% MO can be adsorbed in 60 min and 99.8% MO can be fully removed under visible light illumination in 80 min, owing to the two active {110} and {111} facets and hollow structure. To exactly evaluate the photocatalytic efficiency, a new methodology is proposed by deducting the adsorption effect. The results show that in spite of 99.2% MO is removed from the solution under visible light illumination in 60 min, 14% MO is still adsorbed on the catalyst, which can be totally removed under further 20 min illumination. Our synthesis strategy presents a new opportunity for the preparation of hollow structures with high active facets. And the proposed accurate evaluation methodology may be extended to other photocatalysts with high adsorption capability for organic pollutants.
In this work, two-dimensional Zn carbon nanosheets (CNs) are obtained after heat treatment of in situ synthesized ZIF-8/NaCl nanocomposites , which are ultrasonically mixed with carboxylated multi-walled carbon nanotubes (MWCNTs). Subsequently, the nanocomposites Zn CNs-MWCNTs with large specific surface area and excellent catalytic properties are obtained. Meanwhile, the photoelectric material H–Cu 2 O/CdTe QDs are drop-coated on Zn CNs-MWCNTs/GCE and the modified electrode Zn CNs-MWCNTs/H–Cu 2 O/CdTe QDs/GCE is obtained. Eventually, a novel dopamine photoelectrochemical sensor based on Zn CNs-MWCNTs/H–Cu 2 O/CdTe QDs/GCE is constructed. Among them, the photocurrent intensity of H–Cu 2 O/CdTe QDs is much higher than that of pure H–Cu 2 O and pure CdTe QDs. This is due to the effective combination of CdTe QDs and H–Cu 2 O to form a p-p heterojunction , which can effectively suppress the recombination of electron-hole pairs. Subsequently, the working mechanism of the photoelectrochemical sensor is investigated in depth by the Kubelka-Munk model. At the same time, the photoelectrochemical sensor has reliable selectivity, stability, reproducibility and limit of detection (LOD = 0.3 nM), and also provides a new idea for the detection of dopamine.
Bo Ma,Gailan Ma,Qian Xu,Guoqiang Huang,Hongfang Shen,Maohui Li,Dong Li,Gangli Feng,Yanmin Wang,Youjun Lu
Semiconductor-based photocatalytic technology is considered as an effective and economical approach to solve the degradation of pollutants and the generation of new energy sources. However, suboptimal utilization of solar energy and fast combination of photocarriers greatly affects the catalytic performance. In this paper, plasmonic Hollow-Cu 2 O/Pt nanocages were synthesized by a template method, which have a shell layer with inter-embedded Cu 2 O and Pt nanoparticles subunits heterojunctions. Compared to cubic Cu 2 O and Cu 2 O/Pt, the nanocages exhibit much better photocatalytic properties. 5 mg of Hollow-Cu 2 O/Pt can achieve a degradation efficiency of 91.2 % for methyl orange (20 mg/L) under near-infrared light irradiation, and 96 % for methyl orange (50 mg/L) under visible light irradiation. Moreover, the hollow-Cu 2 O/Pt nanocages offer an enhanced degradation of antibiotics and a photocatalytic hydrogen production evolution, indicating that the nanocages have potential photocatalytic applications for the degradation of different pollutants and the hydrogen evolution. The superior photocatalytic performance is attributed to the synergistic effect of multiple advantages, including the larger specific surface area, the closer d-band center, the multiple diffuse reflection, the LSPR effect and the enhanced local electromagnetic field. This study offers a promising strategy to optimize integrated nanocage cooperated with subunit heterostructure and LSPR effect.
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