Search

The outbreak of the coronavirus (COVID-19) pandemic has forced chemistry teaching from traditional classrooms to online courses worldwide. Herein, we will share some experiences of our online teaching of inorganic chemistry. First, we investigated various teaching platforms and adjusted the online teaching approaches for helping students to be more comfortable with online teaching. During the online class, attention was paid specifically to making the teaching process more topic-focused. This also prompted teachers to interact with students and give feedback in a timely manner. With the student-centered strategy and advanced network technology, we encouraged students to consult literature reports to better digest what they have learned in class and expand their knowledge, thus leading to higher teaching quality and promoting the cultivation of their talents. The overall processes are evaluated by examination, and finally, key points after one-semester online teaching are summarized to further improve future teaching quality. This work provides some rational guidelines toward high-quality online teaching for teachers and could readily expand to courses other than inorganic chemistry.

Triethylamine is a common volatile organic compound (VOC) that plays an important role in areas such as organic solvents, chemical industries, dyestuffs, and leather treatments. However, exposure to triethylamine atmosphere can pose a serious threat to human health. In this study, gas-sensing semiconductor materials of LaFeO3 nano materials with different Mo-doping ratios were synthesized by the sol–gel method. The crystal structures, micro morphologies, and surface states of the prepared samples were characterized by XRD, SEM, and XPS, respectively. The gas-sensing tests showed that the Mo doping enhanced the gas-sensing performance of LaFeO3. Especially, the 4% Mo-doped LaFeO3 exhibited the highest response towards triethylamine (TEA) gas, a value approximately 11 times greater than that of pure LaFeO3. Meantime, the 4% Mo-doped LaFeO3 sensor showed a remarkably robust linear correlation between the response and the concentration (R2 = 0.99736). In addition, the selectivity, stability, response/recovery time, and moisture-proof properties were evaluated. Finally, the gas-sensing mechanism is discussed. This study provides an idea for exploring a new type of efficient and low-cost metal-doped LaFeO3 sensor to monitor the concentration of triethylamine gas for the purpose of safeguarding human health and safety. [ABSTRACT FROM AUTHOR]

Scaling up green hydrogen production from water electrolysis has been recognized as the most effective method to achieve energy sustainability and a carbon-neutral future, in which advanced materials hold the key to high energy conversion efficiency. High-entropy materials (HEMs), containing five or more near equimolar elements, have been in the spotlight as emerging catalysts due to their compositional, structural and functional advantages. Herein, a comprehensive overview of HEMs for catalyzing hydrogen and oxygen evolution reactions (HER and OER) is provided. This review begins with the structures, features of HEMs and the basic principles of electrocatalytic HER and OER, providing the fundamental knowledge and guiding the understanding towards the design concept of HEM catalysts. This review will give a global map of HEMs based on metal entities from noble metals to low cost transition metals, covering the alloys, oxides, phosphides, sulfides and others. Additionally, the rational design, synthetic method, catalytic properties and mechanism investigation have been discussed focusing on the structure–property relationship from experimental and theoretical views. Eventually, the remaining challenges and future development directions have been put forward. This review will provide meaningful guidance to researchers for the exploration of advanced HEMs for water splitting and the disclosure of the underlying mechanism, thus promoting the development. [ABSTRACT FROM AUTHOR]

The sensitive detection of n-propanol, a typical marker molecule in respiratory gases for lung cancer, has attracted much attention from the consideration of health in modern society. However, the identification of n-propanol at the sub-ppm level with rapid responsive ability is a significant challenge but very critical for the early diagnosis of lung cancer. Herein, we demonstrate a unique chromosome-like HoFeO3 nanostructure material, prepared by annealing the self-sacrificial template of easily accessible HoFe-(CN)6, for high-performance n-propanol sensing. In detecting n-propanol, the HoFeO3 material-based sensor exhibits a response of 120.5 to 100 ppm of n-propanol at an operating temperature of 120 °C. Most importantly, it shows a low detection limit of 50 ppb and a good linear relationship between response and concentration. This sensor also possesses a rapid responsive ability with a response time of 4 s. The remarkable sensing performance, greatly outperforming other conventional semiconductor-based chemiresistive gas sensors, can be mainly attributed to the mesoporous structure, various surface element states, and narrow-band traits. The homemade experiment system further validates the practical potential of HoFeO3 microchromosome-based gas sensors for early-stage lung cancer diagnosis. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is the most important chemical and carbon-free energy carrier, which is currently mainly produced by the energy-intensive Haber–Bosch process at high temperatures and pressures. In the spirit of global carbon neutrality and sustainable development, electrochemical nitrogen reduction reaction (NRR) is expected as a promising alternative to the traditional Haber–Bosch process for industrial ammonia production due to both low energy consumption and zero emission of carbon dioxide. However, further breakthroughs in electrochemical NRR strongly depend on the efficiency and selectivity of electrocatalysts. The element Fe has been found to be an important component in nitrogenase enzymes, generating extensive research interest. As one of the most cost-effective and abundant transition metals, iron-based materials have presented great potential for electrochemical NRR. In this review, we summarize recent advances in iron-based materials (including its oxides, chalcogenides, borides, single Fe-atom catalysts, and bimetallic catalysts especially for Fe–Mo-based compounds) towards highly efficient N2-to-NH3 conversion under ambient conditions. Based on recent theoretical and experimental studies, we focus on the structure–property relationship. Strategies to boost NRR performances and perspectives for future developments are comprehensively presented in synthetic protocols, structure modification, activity/selectivity enhancement, and reaction mechanisms to provide insightful guidance for the field of NRR studies. [ABSTRACT FROM AUTHOR]

Nano bowl-like Co–Co6Mo6C2 coated by N,P co-doped carbon (Co–Co6Mo6C2@NPC) is reported as an electrocatalyst for Zn–air batteries. Co–Co6Mo6C2@NPC only needs an overpotential of 210 mV at 10 mA cm−2 for the OER, and the half-wave potential for the ORR is 0.81 V. In addition, the Co–Co6Mo6C2@NPC based battery shows a large open-circuit voltage of 1.335 V and a maximum power density of 160.5 mW cm−2, as well as good stability. The improved catalytic performance can be ascribed to the co-existence of Co6Mo6C2 and Co species to improve the intrinsic catalytic activity, and the bowl-like nanostructure to facilitate the mass transfer. [ABSTRACT FROM AUTHOR]