The incorporation of heteroatoms into carbon aerogels(CAs)can lead to structural distortions and changes in active sites due to their smaller size and electronegativity compared to pure carbon.However,the evolution of...The incorporation of heteroatoms into carbon aerogels(CAs)can lead to structural distortions and changes in active sites due to their smaller size and electronegativity compared to pure carbon.However,the evolution of the electronic structure from single-atom doping to heteroatom codoping in CAs has not yet been thoroughly investigated,and the impact of codoping on potassium ion(K+)storage and diffusion pathways as electrode material remains unclear.In this study,experimental and theoretical simulations were conducted to demonstrate that heteroatom codoping,composed of multiple heteroatoms(O/N/B)with different properties,has the potential to improve the electrical properties and stability of CAs compared to single-atom doping.Electronic states near the Fermi level have revealed that doping with O/N/B generates a greater number of active centers on adjacent carbon atoms than doping with O and O/N atoms.As a result of synergy with enhanced wetting ability(contact angle of 9.26°)derived from amino groups and hierarchical porous structure,ON-CA has the most optimized adsorption capacity(−1.62 eV)and diffusion barrier(0.12 eV)of K^(+).The optimal pathway of K^(+)in ON-CA is along the carbon ring with N or O doping.As K^(+)storage material for supercapacitors and ion batteries,it shows an outstanding specific capacity and capacitance,electrochemical stability,and rate performance.Especially,the assembled symmetrical K^(+)supercapacitor demonstrates an energy density of 51.8 Wh kg^(−1),an ultrahigh power density of 443Wkg^(−1),and outstanding cycling stability(maintaining 83.3%after 10,000 cycles in 1M KPF6 organic electrolyte).This research provides valuable insights into the design of highperformance potassium ion storage materials.展开更多
Fluid catalytic cracking (FCC) salty wastewaters, containing quaternary ammonium compounds (QACs), are very difficult to treat by biochemical process. Anoxic/oxic (A/O) biochemical system, based on nitrification and d...Fluid catalytic cracking (FCC) salty wastewaters, containing quaternary ammonium compounds (QACs), are very difficult to treat by biochemical process. Anoxic/oxic (A/O) biochemical system, based on nitrification and denitrification reactions, was used to assess their possible biodegradation. Because of the negative effects of high salt concentration (3%), heavy metals and toxic organic matter on microorganisms’ activities, some techniques consisting of dilution, coagulation and flocculation, and ozonation pretreatments, were gradually tested to evaluate chemical oxygen demand (COD), ammonia-nitrogen (ammonia-N) and total nitrogen (TN) removal rates. In this process of FCC wastewater, starting with university-domesticated sludge, the ammonia-N and TN removal rates were worst. However, when using domesticated SBR’s sludge and operating with five-fold daily diluted influent (thus reducing salt concentration), the ammonia-N removal reached about 57% while the TN removal rate was less than 37% meaning an amelioration of the nitrification process. However, by reducing the dilution factors, these results were inflected after some days of operation, with ammonia-N removal decreasing and TN barely removed meaning a poor nitrification. Even by reducing heavy metals concentration with coagulation/flocculation process, the results never changed. Thereafter, by using ozonation pre-treatment to degrade the detected organic matter of di-tert-butylphenol and certain isoparaffins, COD, ammonia-N and TN removal rates reached 92%, 62% and 61%, respectively. These results showed that the activities of the microorganisms were increased, thus indicating a net denitrification and nitrification reactions improvement.展开更多
Carbonaceous materials are considered as ideal anode for potassium ion batteries(PIBs)due to their abundant resources and stable physical and chemical properties.However,improvements of reversible capacity and cycle p...Carbonaceous materials are considered as ideal anode for potassium ion batteries(PIBs)due to their abundant resources and stable physical and chemical properties.However,improvements of reversible capacity and cycle performance are still needed,aiming to the practical application.Herein,S/N/O tridoped carbon(SNOC)nanospheres are prepared by in-situ vulcanized polybenzoxazine.The S/N/O tridoped carbon matrix provides abundant active sites for potassium ion adsorption and effectively improves potassium storage capacity.Moreover,the SNOC nanospheres possess large carbon interlayer spacing and high specific surface area,which broaden the diffusion pathway of potassium ions and accelerate the electron transfer speed,resulting in excellent rate performance.As an anode for PIBs,SNOC shows attractive rate performance(438.5 mA h g^(-1) at 50 mA g^(-1) and 174.5 mA h g^(-1) at2000 mA g^(-1)),ultra-high reversible capacity(397.4 mA h g^(-1) at 100 mA g^(-1) after 700 cycles)and ultra-long cycling life(218.9 mA h g^(-1) at 2000 mA g^(-1) after 7300 cycles,123.1 mA h g^(-1) at3000 mA g^(-1) after 16500 cycles and full cell runs for 4000 cycles).Density functional theory calculation confirms that S/N/O tri-doping enhances the adsorption and diffusion of potassium ions,and in-situ Fourier-transform infrared explores explored the potassium storage mechanism of SNOC.展开更多
基金This work is supported by the National Natural Science Foundation of China(No.22103075,No.21827804,and No.22173089)the National Key R&D Program of China(No.2021YFA0716801andNo.2017YFA0303502).
基金financially supported by the Natural Science Foundation of China(Grant No.22005165)the Major Science and Technology Innovation Project of Shandong(Grant No.2019JZZY010507)+1 种基金the Qingdao Municipal Science and Technology Bureau(Grant No.17-1-1-86-jch)the Key Technology Research and Development Program of Shandong(Grant No.2018GGX108005).
文摘The incorporation of heteroatoms into carbon aerogels(CAs)can lead to structural distortions and changes in active sites due to their smaller size and electronegativity compared to pure carbon.However,the evolution of the electronic structure from single-atom doping to heteroatom codoping in CAs has not yet been thoroughly investigated,and the impact of codoping on potassium ion(K+)storage and diffusion pathways as electrode material remains unclear.In this study,experimental and theoretical simulations were conducted to demonstrate that heteroatom codoping,composed of multiple heteroatoms(O/N/B)with different properties,has the potential to improve the electrical properties and stability of CAs compared to single-atom doping.Electronic states near the Fermi level have revealed that doping with O/N/B generates a greater number of active centers on adjacent carbon atoms than doping with O and O/N atoms.As a result of synergy with enhanced wetting ability(contact angle of 9.26°)derived from amino groups and hierarchical porous structure,ON-CA has the most optimized adsorption capacity(−1.62 eV)and diffusion barrier(0.12 eV)of K^(+).The optimal pathway of K^(+)in ON-CA is along the carbon ring with N or O doping.As K^(+)storage material for supercapacitors and ion batteries,it shows an outstanding specific capacity and capacitance,electrochemical stability,and rate performance.Especially,the assembled symmetrical K^(+)supercapacitor demonstrates an energy density of 51.8 Wh kg^(−1),an ultrahigh power density of 443Wkg^(−1),and outstanding cycling stability(maintaining 83.3%after 10,000 cycles in 1M KPF6 organic electrolyte).This research provides valuable insights into the design of highperformance potassium ion storage materials.
文摘Fluid catalytic cracking (FCC) salty wastewaters, containing quaternary ammonium compounds (QACs), are very difficult to treat by biochemical process. Anoxic/oxic (A/O) biochemical system, based on nitrification and denitrification reactions, was used to assess their possible biodegradation. Because of the negative effects of high salt concentration (3%), heavy metals and toxic organic matter on microorganisms’ activities, some techniques consisting of dilution, coagulation and flocculation, and ozonation pretreatments, were gradually tested to evaluate chemical oxygen demand (COD), ammonia-nitrogen (ammonia-N) and total nitrogen (TN) removal rates. In this process of FCC wastewater, starting with university-domesticated sludge, the ammonia-N and TN removal rates were worst. However, when using domesticated SBR’s sludge and operating with five-fold daily diluted influent (thus reducing salt concentration), the ammonia-N removal reached about 57% while the TN removal rate was less than 37% meaning an amelioration of the nitrification process. However, by reducing the dilution factors, these results were inflected after some days of operation, with ammonia-N removal decreasing and TN barely removed meaning a poor nitrification. Even by reducing heavy metals concentration with coagulation/flocculation process, the results never changed. Thereafter, by using ozonation pre-treatment to degrade the detected organic matter of di-tert-butylphenol and certain isoparaffins, COD, ammonia-N and TN removal rates reached 92%, 62% and 61%, respectively. These results showed that the activities of the microorganisms were increased, thus indicating a net denitrification and nitrification reactions improvement.
基金financially supported by the National Natural Science Foundation of China(21975069 and 21872045)the Key Project of Research and Development Plan of Hunan Province(2019SK2071)+1 种基金the Natural Science Foundation of Hunan Province,China(2020JJ4169)the State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Development and Reform Commission of Hunan Province。
文摘Carbonaceous materials are considered as ideal anode for potassium ion batteries(PIBs)due to their abundant resources and stable physical and chemical properties.However,improvements of reversible capacity and cycle performance are still needed,aiming to the practical application.Herein,S/N/O tridoped carbon(SNOC)nanospheres are prepared by in-situ vulcanized polybenzoxazine.The S/N/O tridoped carbon matrix provides abundant active sites for potassium ion adsorption and effectively improves potassium storage capacity.Moreover,the SNOC nanospheres possess large carbon interlayer spacing and high specific surface area,which broaden the diffusion pathway of potassium ions and accelerate the electron transfer speed,resulting in excellent rate performance.As an anode for PIBs,SNOC shows attractive rate performance(438.5 mA h g^(-1) at 50 mA g^(-1) and 174.5 mA h g^(-1) at2000 mA g^(-1)),ultra-high reversible capacity(397.4 mA h g^(-1) at 100 mA g^(-1) after 700 cycles)and ultra-long cycling life(218.9 mA h g^(-1) at 2000 mA g^(-1) after 7300 cycles,123.1 mA h g^(-1) at3000 mA g^(-1) after 16500 cycles and full cell runs for 4000 cycles).Density functional theory calculation confirms that S/N/O tri-doping enhances the adsorption and diffusion of potassium ions,and in-situ Fourier-transform infrared explores explored the potassium storage mechanism of SNOC.
