Interlayer and doping engineering in partially graphitic hollow carbon nanospheres for fast sodium and potassium storage

Constructing anodes with fast ions/electrons transfer paths is an effective strategy to achieve high-performance sodium ion batteries(SIBs)/potassium ion batteries(PIBs). Amorphous carbon is a promising candidate anode for SIBs/PIBs owing to its disordered carbon layers, abundant defects/pores, and lowcost resources. However, the larger radius of Na^(+)/K^(+) leading to depressed kinetics and poor cycling performance, impeding their further applications. Herein, we propose an efficient strategy to construct of nitrogen, sulfur co-doped hollow carbon nanospheres(NS-HCS) involving an in situ growth of polydopamine on nano-Ni(OH)2template with subsequent sulfur doping process. During the formation process, the produced Ni nanospheres play as the hard template and catalyst for the formation of hollow carbon nanosphere with partially graphite microcrystalline structure, while the sulfur doping process can enlarge the interlayer space and create more defects on the surface of carbon nanospheres, thus synchronous improve the Na^(+)/K^(+) insertion and adsorption ability in NS-HCS. With the synergistic control of the enlarged interlayer spacing, high content of pyridinic N/pyrrolic N and graphitization, a hybrid storage mechanism facilitates the transport kinetics and endows the NS-HCS electrode with high capacities and good cycling stability in SIBs and PIB. Benefit from the multiple effects, NS-HCS exhibits the improved capacity of 274.8 m Ah/g at 0.1 A/g and excellent cycling stability of 149.5 m Ah/g after 5000 cycles at2.5A/g in SIBs, as well as good potassium ion storage behavior with a high capacity retention of 76.5%after 700 cycles at 1.0 A/g, demonstrating the potential applications of NS-HCS for high-performance SIBs and PIBs.

Covalent triazine frameworks materials for photo-and electrocatalysis

Covalent triazine frameworks(CTFs)are a class of unique two-dimensional nitrogen-rich triazine framework with adjustable chemical and electronic structures,rich porosity,good stability and excellent semiconductivity,which enable great various applications in efficient gas/molecular adsorption and separation,energy storage and conversion,especially photo-and electrocatalysis.Different synthesis strategies strongly affect the morphology of CTFs and play an important role in their structure and properties.In this concept,we provide a comprehensive and systematic review of the synthesis methods such as ionothermal synthesis,phosphorus pentoxide catalytic method,polycondensation and ultra-strong acid catalyzed method,and applications of CTFs in photo-and electro-catalysis.Finally we offer some insights into the future development progress of CTFs materials for catalytic applications.

CeO_(2)C_(2)Nanoparticles with Oxygen-Enriched Vacancies In-site Self-embedded in Fe,N Co-doped Carbon Nanofibers as Efficient Oxygen Reduction Catalyst for Zn-Air Battery

Rational design of robust non-noble electrocatalysts with numerous oxygen vacancies and highly reactive activity for oxygen reduction reaction(ORR)towards Zn-air batteries is extremely paramount yet challenging.Herein,a novel CeO_(2)C_(2)nanoparticles self-embedded in Fe,N co-doped carbon nanofibers(CeO_(2)C_(2)@Fe-N-C)heterostructure catalyst has been prepared by the in-site dual template assisted electrospinning technique and subsequent high temperature pyrolysis strategy.Thanks to the CeO_(2)C_(2)with oxygen-enriched vacancies and versatile Fe-N-C with rich reactive species and high conductivity,CeO_(2)C_(2)@Fe-N-C catalyst exhibits outstanding catalytic performance in the ORR process,and shows excellent methanol tolerance and cycle stability.In addition,CeO_(2)C_(2)@Fe-N-C delivers a nearly four-electron transfer process in the process of oxygen reduction catalysis,providing a fast-electrochemical kinetic rate,which makes it an efficient air cathode for the Zn-air battery.Importantly,the Zn-air battery fabricated with CeO_(2)C_(2)@Fe-N-C cathode achieves superior performance including large open-circuit voltage(1.5 V)and high specific capacity(780 mAh·g–1 at 10 mA·cm–2)together with superior reversibility and cycling stability,outperforming commercial Pt/C catalyst.The present work introduces a new strategy to design and develop highly active non-noble catalysts and highlights the synergy from heterostructure in oxygen electrocatalysis for advanced Zn-air batteries.

Short-Term Electricity Price Forecasting Using Random Forest Model with Parameters Tuned by Grey Wolf Algorithm Optimization

Accurately forecasting short-term electricity prices is of great significance to electricity market participants.Compared with the time series forecasting methods,machine learning forecasting methods can consider more external factors.The forecasting accuracy of machine learning models is greatly affected by the parameters,meanwhile,the manual selection of parameters usually cannot guarantee the accuracy and stability of the forecasting.Therefore,this paper proposes a random forest(RF)electricity price forecasting model based on the grey wolf optimizer(GWO)to improve the accuracy of forecasting.Among them,RF has a good ability to deal with the problem of non-linear and unstable electricity prices.The optimization of model parameters by GWO can overcome the instability of the forecasting accuracy of manually tune parameters.On this basis,the short-term electricity prices of the PJM power market in four seasons are separately predicted.Experimental results show that the RF algorithm can better predict the short-term electricity price,and the optimization of the RF forecasting model by GWO can effectively improve the accuracy of the RF forecasting model.

Visible-Light Photocatalytic and Photo-bactericidal Activity of Ni-CuWO_(4)/OTiO_(2) Composite

A series of nickel-doped copper tungstate/oxygen-rich TiO_(2) heterojunction-constructed composites of xNi-CuWO_(4)/OTiO_(2) were successfully prepared to demonstrate the enhancement of the visible-light photoactivity through promoting the photogenerated charge carrier separation efficiency.Of all these composites,0.2Ni-CuWO_(4)/OTiO_(2) exhibits excellent and stable visible light photoactivity for the photooxidative coupling of benzylamine to the corresponding N-benzyl-1-phenymethanimine(BPMI)in air atmosphere.The conversion of benzylamine and the selectivity to BPMI reach 97%and 99%,respectively.The catalyst shows good cyclability with the conversion of benzylamine decreasing just by 22%after being repeated six times with the well-maintained selectivity of BPMI.The composite also exhibits excellent photo-bactericidal ability,which greatly inhibits the reproducing of both the Gram-positive bacteria(e.g.,S.epidermidis)and Gram-negative bacteria(e.g.,E.coli).

A misleading way to transform the natural desert into farmland

Yi et al.proposed a concept of“desert soilization”and an idea of“omni-directional integrative(ODI)constraint”in the paper of The Innovation.1 In their practice,a“constraining material”was used to bind the sands in the Ulan Buh Desert.It is claimed that theirmethod can transform the desert into farmland.We havemany doubts about this method and disagree with their viewpoints.We would like to discuss these questions and clarify our stand here.Yi et al.should make it clear that their test is only valid in areas with shallow groundwater levels.