CdSe x Te 1−x alloyed colloidal quantum dots show great potential application on quantum dot-sensitized solar cells (QDSCs) due to its relatively wide light absorption range and high chemical stability. In this respect, a thin Mn modified CdSe layer is introduced into TiO 2 /CdSe x Te 1−x alloyed QDs surface via a simple chemical bath deposition method (CBD) in order to further improve the cell performance. The power conversion efficiency of CdSe x Te 1−x QDSCs has been improved to 8.14%. Detailed investigation on the influence of this modification toward the TiO 2 /CdSe x Te 1−x interface on the cell performance reveals that introduction of Mn into CdSe QDs is found to facilitate the Mn-doped CdSe deposition and improve the light absorption of the device. In the meantime, the existence of the (Mn-)CdSe layer can also work as a passivation layer to reduce charge recombination.
In this study, a Mn-modified Pt-based catalyst loaded on nitrogen-doped Ketjen black (Mn-Pt/NKB) is prepared using a simple ethylene glycol reduction method. The size of Pt nanoparticles (NPs) is effectively controlled by doping with Mn and N. With the smallest average particle size of 1.7 nm, Mn-Pt/NKB demonstrates half-wave potentials of 0.890 and 0.688 V in the alkaline and neutral electrolytes, respectively, which are superior to those of commercial platinum on activated carbon (Pt/C). When applied as an air cathode in aluminum-air battery, it exhibits ultra-high power densities of 190 (alkaline) and 26.2 mW·cm −2 (neutral). Moreover, the voltage remains stable after 5 h of discharge. The practical application performance of the Mn-Pt/NKB catalyst in an aluminum-air battery is better than that of commercial Pt/C. Furthermore, the oxygen reduction reaction (ORR) mechanism on surfaces with different particle sizes is analyzed using density functional theory. Oxygen cracking is the major pathway on the surface of the small particles with lower energy consumption of 0.5 eV, while water molecule cleavage is the major pathway on the surface of the large particles with higher energy consumption of 0.97 eV. The lower energy consumption of the oxygen cracking pathway further confirms the ORR mechanism for higher activity on small-sized surfaces. This study provides a direction for the rational design of Pt-based catalysts for ORR and sheds light on the commercial development of aluminum-air batteries.
Sun Yanlong,Zheng Tong,Zhang Guangshan,Liu Bei,Wang Peng
The regeneration of adsorbent by thermal method may transfer the adsorbed organic pollutants into the air phase. Herein, manganese and cerium are loaded on adsorbent as catalyst to mineralize the adsorbed organic pollutants during regeneration. The modified adsorbent is characterized by scanning electron microscope-energy dispersive spectrometer, Brunauer Emmett Teller-Barrett Joyner Halenda, and X-ray photoelectron spectroscopy. Regeneration of modified adsorbent is evaluated by adsorbent yield and mineralization percentage of the absorbed organic pollutants. The results demonstrate that the mineralization percentage of tetracycline increased about 100% after the modification. Besides, the loaded catalyst can significantly reduce the regeneration temperature. Furthermore, cerium can reduce the adverse impact causes by manganese which will decrease the adsorption capacity of adsorbent. Kinetics, equilibrium, thermodynamic, and other adsorption properties of modified adsorbent towards tetracycline are further studied. The theoretical maximum of adsorption capacity calculated by Langmuir model is 196.4 mg g −1 , and the kinetics of adsorption fits pseudo-second-order model. The adsorption of tetracycline on the adsorbent is feasible, spontaneous, and endothermic. The properties of synthesized composite material are stable; the yield of Ce/Mn/Al 2 O 3 adsorbent can keep higher than 95% even after five adsorption/regeneration cycles. This research provides another perspective on the design and regeneration of adsorbent, which focus on reducing the secondary pollution during adsorbent regeneration process.
The extensive presence of organic micropollutants in complex water matrices requires the development of selective oxidation technologies . In this study, a novel selective oxidation process was developed via the conjunction of FeMn/CNTs with peroxymonosulfate and successfully used to remove micropollutants such as sulfamethoxazole (SMX) and bisphenol A from aqueous solutions. FeMn/CNTs were prepared using a facile co-precipitation method, characterized using a series of surface characterization techniques, and then tested for pollutant removal . The results showed that the FeMn/CNTs had much greater reactivity than CNTs , manganese oxide , and iron oxide . The pseudo-first-order rate constant with FeMn/CNTs was more than 2.9–5.7 times that of the other tested materials. The FeMn/CNTs had great reactivity in a wide range of pH values from 3.0 to 9.0, with the best reactivity found at pH values of 5.0 and 7.0. High-valent metal-oxo species such as Fe(IV) O and Mn(IV) O and superoxide anion radicals were determined to be the reactive species and were responsible for the oxidation of SMX. These reactive species were selective; therefore, the overall removal performance of SMX was not obviously influenced by high levels of water components including chloride ions, bicarbonates , and natural organic matters. The results from this study may promote the design and application of selective oxidation technologies for micropollutant abatement.
危险品化学品经营许可证（带存储）