Paper-based aqueous Al ion battery with water-in-salt electrolyte

Low-cost,flexible and safe battery technology is the key to the widespread usage of wearable electronics,among which the aqueous Al ion battery with water-in-salt electrolyte is a promising candidate.In this work,a flexible aqueous Al ion battery is developed using cellulose paper as substrate.The water-in-salt electrolyte is stored inside the paper,while the electrodes are either printed or attached on the paper surface,leading to a lightweight and thin-film battery prototype.Currently,this battery can tolerate a charge and discharge rate as high as 4 A g^(-1) without losing its storage capacity.The charge voltage is around 2.2 V,while the discharge plateau of 1.6–1.8 V is among the highest in reported aqueous Al ion batteries,together with a high discharge specific capacity of~140 mAh g^(-1).However,due to the water electrolysis side reaction,the faradaic efficiency can only reach 85%with a cycle life of 250 due to the dry out of electrolyte.Benefited from using flexible materials and aqueous electrolyte,this paper-based Al ion battery can tolerate various deformations such as bending,rolling and even puncturing without losing its performance.When two single cells are connected in series,the battery pack can provide a charge voltage of 4.3 V and a discharge plateau as high as 3–3.6 V,which are very close to commercial Li ion batteries.Such a cheap,flexible and safe battery technology may be widely applied in low-cost and large-quantity applications,such as RFID tags,smart packages and wearable biosensors in the future.

Mechanistic study of vacuum UV catalytic oxidation for toluene degradation over CeO_(2) nanorods

The present study specifically investigates vacuum ultraviolet (VUV) catalytic oxidation for toluene degradation over CeO_(2) nanorods.Synergetic effects of ultraviolet photocatalytic oxidation (UV-PCO) and ozone catalytic oxidation (OZCO) were manifested in the results of toluene removal and COx generation,while the combination of UV-PCO andOZCO (UV-OZCO) did not lead to improvement of mineralization.All the processes contribute to ozone decomposition,but no obvious synergetic effects of the different processes can be observed.Intermediate analysis results indicated that more toluene was oxidized into by-products,such as benzyl alcohol and benzaldehyde,by UV-OZCO rather than forming COx.Both hydroxyl radical (·OH) and superoxide radical (·O_(2)^(-)) were found in all the processes of the VUV-PCO-OZCO system(combination of VUV photolysis,UV-PCO,OZCO and UV-OZCO processes).In the UV-OZCO process,the formation of hydroxyl radical was promoted,while that of superoxide radical was impeded,resulting in lower mineralization level of toluene.The mechanistic study of toluene degradation over CeO_(2) nanorods in the VUV-PCO-OZCO system revealed that with the formation of·O_(2)^(-)and·OH,toluene is first oxidized to intermediates,followed by further ring–opening reaction and,finally,degradation into CO_(2) and H_(2)O.CeO_(2) nanorods function as both ozonation catalyst and photocatalyst,and the redox pair of Ce^(3+)and Ce^(4+)are interconvertible and can keep a balance.

UV light-induced oxygen doping in graphitic carbon nitride with suppressed deep trapping for enhancement in CO_(2) photoreduction activity

While photoreduction of CO_(2) to CH 4 is an effective means of producing value-added fuels,common pho-tocatalysts have poor activity and low selectivity in photocatalytic CO_(2)-reduction processes.Even though creating defects is an effective photocatalyst fabrication route to improve photocatalytic activity,there are some challenges with the facile photocatalyst synthesis method.In this work,an O element is in-troduced into a graphitic carbon nitride(CN)skeleton through a precursory ultraviolet light irradiation pretreatment to increase the visible light absorption and enhance the carrier density of this modified non-metal CN photocatalyst;the charge transfer dynamics thereof are also studied through electrochem-ical tests,photoluminescence spectroscopy,and nanosecond transient absorption.We verify that the op-timized sample exhibits lower charge recombination and a suppressed 84 ns electron-trapping lifetime,compared to the 103 ns electron-trapping lifetime of the CN counterpart,and thereby contributes to ro-bust detrapping and a fast transfer of active electrons.Through density functional theory calculations,we find that the improved light absorption and increased electron density are ascribed to O-element doping,which enhances the CO_(2) adsorption energy and improves the CO_(2)-to-CH 4 photoreduction activity;it be-comes 17 times higher than that of the bare CN,and the selectivity is 3.8 times higher than that of CN.Moreover,the optimized sample demonstrates excellent cyclic stability in a 24-hour cycle test.

Low-cost and efficient Mn/CeO_(2) catalyst for photocatalytic VOCs degradation via scalable colloidal solution combustion synthesis method

Colloidal solution combustion synthesis(CSCS)is a simple and easy method for mass-production of crystalline nanomaterials with tunable pore structure.In this work,mesoporous Mn/CeO_(2) catalysts were fabricated via CSCS method coupled with a dip-coating process and used for photocatalytic oxidation(PCO)of toluene.Under vacuum ultraviolet(VUV)irradiation,a high toluene removal efficiency of about 92%was achieved with a toluene reaction rate of about 118μmol/g/h in a continuous flow reactor.A possible degradation pathway was proposed based on the analysis of intermediates by Fourier transform infrared photoluminescence spectra(FTIR)and GC-Mass.Hydrogen temperature-programmed reduction(H_(2)-TPR),Brunauer-Emmett-Teller(BET)surface areas,photoluminescence spectra(PL)spectra and X-ray photoelectron spectroscopy(XPS)were carried out to analyze physical and chemical properties of the catalysts.Compared with Mn_(x)Ce_(1-x)O_(2) catalysts synthesized by one step CSCS method,Mn/CeO_(2) has a higher photocatalytic activity,which is attributed to the presence of higher contents of Ce^(3+),Mn^(2+)and Mn^(3+)species.The presence of higher contents of these species plays a key role in the activity enhancement of toluene oxidation and ozone decomposition.This method is facile,efficient and scalable,and it may become a promising industrial application technology for catalyst synthesis in the near future.

行业研报、公司研报与分析师乐观偏差

分析师的股票评级和盈余预测为何往往过度乐观?本文对比分析师的公司研报和行业研报,发现研报的表达特征和发布周期是影响分析师乐观偏差的重要因素。本文对2010-2019年我国近27万份行业研报进行文本分析,发现分析师在行业研报中会择优推荐少数股票,与公司研报中普遍给出“买入”评级形成鲜明对比;同时,行业研报通常以固定频率定期发布,避免了分析师通过公司研报反映负面信息的主观择时。实证结果表明,行业研报“择优推荐”和“定期发布”的特征使其具有独特的信息价值:行业研报中的个股推荐强度,以及公司研报和行业研报间的推荐差异度能解释分析师的乐观偏差,且能预测公司的股票收益、基本面表现、分析师新增跟踪、盈余预测修正和评级调整。