A spinel oxide NiCo204 prepared by thermal decomposition is of very high activity for the oxygen evolution reaction(OER)in alkaline solution.The oxygen evolution overpotential on NiCo204 is 0.252-0.262V in 10 M NaOH s...A spinel oxide NiCo204 prepared by thermal decomposition is of very high activity for the oxygen evolution reaction(OER)in alkaline solution.The oxygen evolution overpotential on NiCo204 is 0.252-0.262V in 10 M NaOH solution at 343K and current density 100 mAcm^(-2).展开更多
A novel series of photocatalysts, bismuth oxyhalide (BiOX, X = Cl, Br, and Ⅰ), were synthesized by a hydrolysis method. The powder sampies were characterized by the use of X-ray diffraction (XRD), scanning electr...A novel series of photocatalysts, bismuth oxyhalide (BiOX, X = Cl, Br, and Ⅰ), were synthesized by a hydrolysis method. The powder sampies were characterized by the use of X-ray diffraction (XRD), scanning electron microscope, and UV-Vis spectrophotometer. The XRD pattern showed that all the BiOX were well crystallized in the tetragonal structure. The band gaps of the sheet-shaped compounds BiOX (X = Cl, Br, andⅠ) were 3.44, 2.76, and 1.85 eV, respectively. BiOBr showed the highest photocatalytic activity in degrading rhodamine B (RhB) and evolving 02 for its proper valence band (VB). BiOI has no photocatalytic activity. BiOCl showed the highest activity in decomposing isopropanol because of electron-hole pair separation through trapping electrons by oxygen vacancies.展开更多
Green reactions not only provide us chemical products without any pollution,but also offer us the viable technology to realize difficult tasks in normal conditions.Photo-,photoelectro-,and electrocatalytic reactions a...Green reactions not only provide us chemical products without any pollution,but also offer us the viable technology to realize difficult tasks in normal conditions.Photo-,photoelectro-,and electrocatalytic reactions are indeed powerful tools to help us to embrace bright future.Especially,some gas-involved reactions are extremely useful to change our life environments from energy systems to liquid fuels and cost-effective products,such as H2 evolution(H2 production),02 evolution/reduction,CO2 reduction,N2 reduction(or N2 fixation) reactions.We can provide fuel cells clean H2 for electric vehicles from H2 evolution reaction(HER),at the same time,we also need highly efficient 02 reduction reaction(ORR) in fuel cells for improving the reaction kinetics.Moreover,we can get the clean oxidant O2 from water through O2 evolution reaction(OER),and carry out some reactions without posing any pollution to reaction systems.Furthermore,we can translate the greenhouse gas CO2 into useful liquid fuels through CO2 reduction reaction(CRR).Last but not the least,we can get ammonia from N2 reduction reaction(NRR),which can decrease energy input compared to the traditional Hubble process.These reactions,such as HER,ORR,OER,CRR and NRR could be realized through solar-,photoelectro-and electro-assisted ways.For them,the catalysts used play crucial roles in determining the efficiency and kinds of products,so we should consider the efficiency of catalysts.However,the cost,synthetic methods of catalysts should also be considered.Nowadays,significant progress has been achieved,however,many challenges still exist,reaction systems,catalysts underlying mechanisms,and so on.As extremely active fields,we should pay attention to them.Under the background,it has motivated us to contribute with a roadmap on ’GasInvolved Photo-and Electro-Catalysis’.展开更多
Electrocatalysts with high catalytic activity and stability play a key role in promising renewable energy technologies, such as fuel cells and metal-air batteries. Here, we report the synthesis of Fe/Fe203 nanoparticl...Electrocatalysts with high catalytic activity and stability play a key role in promising renewable energy technologies, such as fuel cells and metal-air batteries. Here, we report the synthesis of Fe/Fe203 nanoparticles anchored on Fe-N-doped carbon nanosheets (Fe/Fe2Og@Fe-N-C) using shrimp shell-derived N-doped carbon nanodots as carbon and nitrogen sources in the presence of FeCI3 by a simple pyrolysis approach. Fe/Fe203@Fe-N-C obtained at a pyrolysis temperature of 1,000 ℃ (Fe/Fe2OB@Fe-N-C-1000) possessed a mesoporous structure and high surface area of 747.3 m2-g-1. As an electrocatalyst, Fe/Fe203@Fe-N-C-1000 exhibited bifunctional electrocatalytic activities toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline media, com- parable to that of commercial Pt/C for ORR and RuO2 for OER, respectively. The Zn-air battery test demonstrated that Fe/Fe2OB@Fe-N-C-1000 had a superior rechargeable performance and cycling stability as an air cathode material with an open drcuit voltage of 1.47 V (vs. Ag/AgCl) and a power density of 193 mW.cm-2 at a current density of 220 mA-cm-2. These performances were better than other commercial catalysts with an open circuit voltage of 1.36 V and a power density of 173 mW-cm^-2 at a current density of 220 mA.cm-2 (a mixture of commercial Pt/C and RuO2 with a mass ratio of 1:1 was used for the rechargeable Zn-air battery measurements). This work will be helpful to design and develop low-cost and abundant bifunctional oxygen electrocatalysts for future metal-air batteries.展开更多
The development of visible-light-responsive photocatalysts for promoting solar-driven oxygen(O2)production from water splitting is a potentially attractive but still a challenging scheme.In the present work,a(111)-typ...The development of visible-light-responsive photocatalysts for promoting solar-driven oxygen(O2)production from water splitting is a potentially attractive but still a challenging scheme.In the present work,a(111)-type layered perovskite oxynitride,Sr5Nb4O15-xNx,was synthesized via the nitridation treatment of the disk-like oxide precursor under the ammonia flow,which was fabricated using a flux method.The homogeneous dispersion of nitrogen(N)dopant in N-doped Sr5Nb4O15 was ascertained by energy-dispersive X-ray spectroscopy characterization,and the Sr5Nb4O15-xNx was found to be a direct semiconductor with a light absorption edge of approximately 640 nm.Density functional theory investigation implies that the hybridization between the outmost N 2p orbitals and O 2p orbitals upshifts the original valence band maximum of Sr5Nb4O15 and endows its visible-light-responsive characteristics.Loading with cobalt oxide(CoOx)as cocatalyst,the as-prepared Sr5Nb4O15-xNx exhibited an enhanced photocatalytic O2 evolution activity from water splitting under visible-light illumination(λ>420 nm).Moreover,another homogeneous N-doped layered perovskite-type niobium(Nb)-based oxynitride,Ba5Nb4O15-xNx,was also developed and investigated for the visible-light-actuated O2 production,highlighting the versatility of the present approach for exploring novel visible-light-responsive photocatalysts.展开更多
文摘A spinel oxide NiCo204 prepared by thermal decomposition is of very high activity for the oxygen evolution reaction(OER)in alkaline solution.The oxygen evolution overpotential on NiCo204 is 0.252-0.262V in 10 M NaOH solution at 343K and current density 100 mAcm^(-2).
基金This study was financially supported by the National Natural Science Foundation of China(No.50471004)the Program for New Century Excellent Talents in Universities,and the Foundation from Engineering Research Institute,Peking University(No.204031)
文摘A novel series of photocatalysts, bismuth oxyhalide (BiOX, X = Cl, Br, and Ⅰ), were synthesized by a hydrolysis method. The powder sampies were characterized by the use of X-ray diffraction (XRD), scanning electron microscope, and UV-Vis spectrophotometer. The XRD pattern showed that all the BiOX were well crystallized in the tetragonal structure. The band gaps of the sheet-shaped compounds BiOX (X = Cl, Br, andⅠ) were 3.44, 2.76, and 1.85 eV, respectively. BiOBr showed the highest photocatalytic activity in degrading rhodamine B (RhB) and evolving 02 for its proper valence band (VB). BiOI has no photocatalytic activity. BiOCl showed the highest activity in decomposing isopropanol because of electron-hole pair separation through trapping electrons by oxygen vacancies.
基金The financial support from the National Natural Science Foundation of China (Nos. 51772312, 21671197)
文摘Green reactions not only provide us chemical products without any pollution,but also offer us the viable technology to realize difficult tasks in normal conditions.Photo-,photoelectro-,and electrocatalytic reactions are indeed powerful tools to help us to embrace bright future.Especially,some gas-involved reactions are extremely useful to change our life environments from energy systems to liquid fuels and cost-effective products,such as H2 evolution(H2 production),02 evolution/reduction,CO2 reduction,N2 reduction(or N2 fixation) reactions.We can provide fuel cells clean H2 for electric vehicles from H2 evolution reaction(HER),at the same time,we also need highly efficient 02 reduction reaction(ORR) in fuel cells for improving the reaction kinetics.Moreover,we can get the clean oxidant O2 from water through O2 evolution reaction(OER),and carry out some reactions without posing any pollution to reaction systems.Furthermore,we can translate the greenhouse gas CO2 into useful liquid fuels through CO2 reduction reaction(CRR).Last but not the least,we can get ammonia from N2 reduction reaction(NRR),which can decrease energy input compared to the traditional Hubble process.These reactions,such as HER,ORR,OER,CRR and NRR could be realized through solar-,photoelectro-and electro-assisted ways.For them,the catalysts used play crucial roles in determining the efficiency and kinds of products,so we should consider the efficiency of catalysts.However,the cost,synthetic methods of catalysts should also be considered.Nowadays,significant progress has been achieved,however,many challenges still exist,reaction systems,catalysts underlying mechanisms,and so on.As extremely active fields,we should pay attention to them.Under the background,it has motivated us to contribute with a roadmap on ’GasInvolved Photo-and Electro-Catalysis’.
基金This work was financially supported by the National Natural Science Foundation of China (Nos. 51372248 and 51432009), the Instrument Developing Project of the Chinese Academy of Sciences (No. yz201421) and the CAS/SAFEA International Partnership Program for Creative Research Teams of Chinese Academy of Sciences, the CAS Pioneer Hundred Talents Program and the Users with Potential Program (No. 2015HSC- UP006, Hefei Science Center, CAS), China.
文摘Electrocatalysts with high catalytic activity and stability play a key role in promising renewable energy technologies, such as fuel cells and metal-air batteries. Here, we report the synthesis of Fe/Fe203 nanoparticles anchored on Fe-N-doped carbon nanosheets (Fe/Fe2Og@Fe-N-C) using shrimp shell-derived N-doped carbon nanodots as carbon and nitrogen sources in the presence of FeCI3 by a simple pyrolysis approach. Fe/Fe203@Fe-N-C obtained at a pyrolysis temperature of 1,000 ℃ (Fe/Fe2OB@Fe-N-C-1000) possessed a mesoporous structure and high surface area of 747.3 m2-g-1. As an electrocatalyst, Fe/Fe203@Fe-N-C-1000 exhibited bifunctional electrocatalytic activities toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline media, com- parable to that of commercial Pt/C for ORR and RuO2 for OER, respectively. The Zn-air battery test demonstrated that Fe/Fe2OB@Fe-N-C-1000 had a superior rechargeable performance and cycling stability as an air cathode material with an open drcuit voltage of 1.47 V (vs. Ag/AgCl) and a power density of 193 mW.cm-2 at a current density of 220 mA-cm-2. These performances were better than other commercial catalysts with an open circuit voltage of 1.36 V and a power density of 173 mW-cm^-2 at a current density of 220 mA.cm-2 (a mixture of commercial Pt/C and RuO2 with a mass ratio of 1:1 was used for the rechargeable Zn-air battery measurements). This work will be helpful to design and develop low-cost and abundant bifunctional oxygen electrocatalysts for future metal-air batteries.
基金the financial support from the National Key R&D Program of China(No.2020YFA0406102)the National Natural Science Foundation of China(Nos.21633009 and 21925206)+2 种基金the International Partnership Program of Chinese Academy of Sciences(No.121421KYSB20190025)the Dalian National Laboratory for Clean Energy(DNL)Cooperation Fund,CAS(No.DNL 201913)the DICP Foundation of Innovative Research(No.DICP I201927)。
文摘The development of visible-light-responsive photocatalysts for promoting solar-driven oxygen(O2)production from water splitting is a potentially attractive but still a challenging scheme.In the present work,a(111)-type layered perovskite oxynitride,Sr5Nb4O15-xNx,was synthesized via the nitridation treatment of the disk-like oxide precursor under the ammonia flow,which was fabricated using a flux method.The homogeneous dispersion of nitrogen(N)dopant in N-doped Sr5Nb4O15 was ascertained by energy-dispersive X-ray spectroscopy characterization,and the Sr5Nb4O15-xNx was found to be a direct semiconductor with a light absorption edge of approximately 640 nm.Density functional theory investigation implies that the hybridization between the outmost N 2p orbitals and O 2p orbitals upshifts the original valence band maximum of Sr5Nb4O15 and endows its visible-light-responsive characteristics.Loading with cobalt oxide(CoOx)as cocatalyst,the as-prepared Sr5Nb4O15-xNx exhibited an enhanced photocatalytic O2 evolution activity from water splitting under visible-light illumination(λ>420 nm).Moreover,another homogeneous N-doped layered perovskite-type niobium(Nb)-based oxynitride,Ba5Nb4O15-xNx,was also developed and investigated for the visible-light-actuated O2 production,highlighting the versatility of the present approach for exploring novel visible-light-responsive photocatalysts.