Performance In Stability Tests Research Articles

Highly dispersed Co nanoparticles confined by mesopore-rich N-doped hollow carbon nanotubes for efficient oxygen reduction reaction and Zn-air battery

Oxygen reduction reaction (ORR) is an important reaction process in Zn-air batteries, and the catalyst plays a crucial role as the cathode in the system. However, the reported catalysts often exhibit poor durability and stability in the operation of air batteries. Here, we used g-C3N4 as a precursor to mix Co nanoparticles for carbonization, and synthesized a large number of carbon nanotubes (CNTs) interwoven cluster catalysts, namely Co/CNT-800. The obtained catalyst has a rolling grass like morphology, forming a highly conductive network, which helps to improve the electron transfer ability in the ORR process. At the same time, the influence of materials at different carbonization temperatures on the ORR of Zn-air batteries was studied. In alkaline media, Co/CNT-800 showed the high ORR performance, with a half-wave potential of 0.839 V (vs. RHE, Pt/C 0.845 V). After 5000 cycles, the E1/2 of the Co/CNT-800 catalyst only decreased by 9 mV, and its performance in stability tests and methanol tolerance tests was superior to Pt/C. When Co/CNT-800 catalyst is used as the air cathode for Zn-air batteries, it exhibits an excellent specific capacity of 709.2 mAh/g and a power density of 142.2 mW cm−2.This research achievement provides valuable insights for the development of high-performance Zn-air batteries and innovative guidance for the design of ORR catalysts.

P‐Type Doping of PM6:Y6‐Based Photoactive Layer with Formic Acid

The introduction of molecular doping process is necessary to enhance the optic and electronic properties of organic semiconductors for facilitating charge transport. In particular, since the doping process has a positive influence on the charge transfer interaction between host semiconductor and dopant, improved mobility has been efficiently achieved. Despite its advantages, doping technologies in organic solar cells (OSCs) are emphasized to the development of n‐type dopants used for balancing the electron and hole. In addition, since the bulk‐heterojunction microstructure in OSCs has randomly blended phases of the donor and acceptor, it is important to optimize charge extraction without loss by controlling the morphology. Herein, OSCs by p‐type doping with formic acid (FA) into a photoactive layer is reported. The champion device yields a significantly improved power conversion efficiency from 14.3% to 15.3% with a high fill factor of 71.7%. It is found that the p‐doped photoactive layer exhibits enhanced conductivity, improved carrier mobilities, suppressed charge recombination, and lowered leakage current. The FA simultaneously acts as a film morphology controller of the photoactive layer with enhanced phase separation to transport the charge efficiently. Thus, the doping process with FA can maintain the device performance in stability tests (95.6% remaining).

One Test System Design of Static Stiffness for Machine Tools

Computer is regarded as a center of signal detection, data processing and control in this system, accompanied by precision displacement sensors, pressure sensors and stepper motors and drives. Realize the transition of analog to digital with A/D converter board by VB6.0, and load simulation device steady and uniform by stepper motor, at the same time realize the functions of data calculation processing, storage, querying and sample curve drawing. The experimental results shows that the system has the advantages of a high degree of automation, high test efficiency, high precision, high reliability, stability test performance.

High activity and stability of the Rh‐free Co‐based ex‐hydrotalcite containing Pd in the catalytic decomposition of N2O

The catalytic decomposition of nitrous oxide to nitrogen and oxygen has been studied over calcined hydrotalcite‐like compounds containing different combinations of bivalent (Co, Pd, Mg) and trivalent (Al, La, Rh) cations with carbonate as interlayer anion. The precursors were prepared by co‐precipitation under low supersaturation conditions and characterized by XRD and TG/DSC. The mixed oxides derived after calcination at 723 K were characterized by XRD, N2 adsorption at 77 K, and XRF. The presence of Rh, La, or Pd in the Co‐based HTlc's improves considerably the catalytic activity. Co–Rh,Al‐HTlc (Co/Rh/Al==3/0.02/1) proved to be a very active catalyst, although the presence of the noble metal Pd in this catalyst ex‐Co,Pd–La,Al‐HT (Co/Pd/La/Al=3/1/1/1) produces a similar catalytic activity to that of Rh‐containing catalyst, both in a N2O‐containing stream and in one containing also SO2 and O2, but with a better performance in stability tests. PdO phase has been identified by XRD as being responsible for the considerable improvement in the activity. The presence of Mg as spinel structure exerts a stabilizing effect in the more active catalysts when mixtures of SO2 and O2 are considered.