The development of rechargeable lithium−oxygen (Li−O2) batteries with high specific energy is essential to satisfy increasing energy consumption. It is critical to understand the dynamic process and detailed pathways during cell operation, which will allow us to control the reaction, suppress the formation of byproducts, and optimize battery performance. In situ vibrational spectroelectrochemical techniques, including in situ Raman spectroscopy and in situ Fourier Transform Infrared (FTIR) spectroscopy, are powerful analytical methods for the purposes of battery studies and are reviewed in this article. The two in situ techniques can acquire real‐time information of adsorbed species on the interface of the electrode, and reveal the reaction mechanism on the interface of the electrode/electrolyte in depth. In situ Raman technique mainly monitors intermediate species and products in Li−O2 batteries. The applications of surface‐enhanced Raman spectroscopy (SERS) for Li−O2 batteries are described in detail in the review. For the in situ FTIR technique, two commonly used in situ methods are introduced in Li−O2 batteries, namely, subtractive normalized Fourier transform infrared spectroscopy (SNIFTIRS) and attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR‐SEIRAS). The reaction mechanism and failure mechanism of the cell are discussed by using the in situ FTIR technique.

Electrochemical CO2 reduction to value-added chemicals provides an efficient way to lower global warming if using efficient and selective electrocatalysts. However, the search and design of such electrocatalysts remain a considerable challenge. Here, in this work, the performance of Pt13−nMn (M = Mn, Fe, Co, Ni, Cu, and Zn) bimetallic catalysts was systematically studied in this work using spin-polarized density functional theory calculations. The Gibbs free energy results show that the doping of Mn to the Pt clusters was more beneficial to the improvement of the catalyst activity, following is the addition of Zn and Co. Among all the clusters, 15 nanoclusters are promising catalysts with a barrier of ΔG <1 eV. The Pt8Mn5, Pt2Mn11, and Pt11Mn2 are the three most promising catalysts with the barrier of only 0.148, 0.237, and 0.286 eV, respectively, displaying all more than 1 eV lower than that of pure Pt13. For most of the Pt13−nMn (M = Mn, Fe, Co, Ni, Cu, and Zn) systems, the desorption of CO is the rate-limiting step. The d band center of Pt8Mn5 is far from the Fermi energy level, which causes CO detachment more easily from Pt8Mn5. Pt8Mn5 exhibits superior catalytic activity toward CO. The study can be used to guide the design of bimetallic catalysts in the future.

BACKGROUND: Phenolic pollutant contamination is a serious problem. The advanced oxidation process based on sulfate radicals (SR-AOPs) is an efficient technology for the degradation of phenolic contaminants in the aquatic environment. Bimetallic nanomaterials have attracted much attention because of their excellent catalytic performance in activating peroxymonosulfate (PMS). Herein, 3D mesoporous NiCo 2 O 4 hollow petal spheres with a specific surface area of 252.35 m 2 g −1 were successfully prepared.RESULTS: In the NiCo 2 O 4 /PMS system, phenol (50 mg L −1 ) was absolutely removed within 25 min with a degradation rate constant (k) of 0.19651 min −1 , which is 6.2 times higher than that of the Co 3 O 4 /PMS system. The excellent catalytic activity of NiCo 2 O 4 is attributed to the larger amount of redox cycles of Co 3+ /Co 2+ and Ni 3+ /Ni 2+ as well as its large specific surface area and multi-step pore channel structure. Moreover, the related influencing factors were systematically researched in the NiCo 2 O 4 /PMS system, including reaction temperature, solution pH, initial concentration, catalyst and PMS dose, as well as matrix species (HCO 3 − , Cl − , NO 3 − , and humic acid). The recycling tests revealed the outstanding chemical stability of NiCo 2 O 4 . The electron paramagnetic resonance (EPR) and quenching experiments verify that sulfate radical (SO 4 • −) acts as the leading role for phenol decomposition. The possible degradation path was proposed based on the several major degradation intermediates that were detected by Gas Chromatography-Mass Spectrometer (GC-MS).CONCLUSION: This research provides a facile and mild method for the fabrication of promising 3D heterogeneous catalysts for PMS activation and provides a green and promising technology for effective contaminant control in modern wastewater remediation.