A low-cost,highly efficient and strong durable bifunctional electrocatalyst is crucial for electrochemical overall water splitting.In this paper,a self-templated strategy combined with in-situ phosphorization is appli...A low-cost,highly efficient and strong durable bifunctional electrocatalyst is crucial for electrochemical overall water splitting.In this paper,a self-templated strategy combined with in-situ phosphorization is applied to construct hollow structured bimetallic cobalt-nickel phosphide(CoNiP_(x))nanocages.Owing to their unique hollow structure and bimetallic synergistic effects,the as-synthesized CoNiP_(x)hollow nanocages exhibit a high electrocatalytic activity and stability towards hydrogen evolution reaction in all-pH electrolyte and a remarkable electrochemical performance for oxygen evolution reaction in 1.0 mol L^(-1)KOH.Meanwhile,with the bifunctional electrocatalyst in both anode and cathode for overall water splitting,a low voltage of 1.61 V and superior stability are achieved at a current density of 20 mA cm^(-2).展开更多
Metal-organic frameworks(MOFs) as promising electrodes for supercapacitors are attracting increasing research interest. Herein, we report an effective strategy to improve the electrochemical performance of Ni-MOF for ...Metal-organic frameworks(MOFs) as promising electrodes for supercapacitors are attracting increasing research interest. Herein, we report an effective strategy to improve the electrochemical performance of Ni-MOF for supercapacitor by introducing a secondary Co ion. The Co substitution of Ni in Ni-MOF can improve the intrinsic reactivity and stability. As a result, the bimetallic Co/Ni-MOF-1:15 with an optimal Co/Ni ratio delivers high specific capacitance(359 F/g at 0.5 A/g), good rate performance(81.5% retention at 5 A/g) and cycling stability(81% retention after 5000 cycles). These results demonstrate that the bimetallic synergistic strategy is an effective way to improve the pseudocapacitive performance of MOFs.展开更多
Three kinds of dialkylphosphinic acids(DAPAs),i.e.dihexylphophinic acid(DHPA),di-(2,4,4-trimethylpentyl) phosphinic acid(DTMPPA)and didecylphophinic acid(DDPA),were synthesized through free radical addition reaction.T...Three kinds of dialkylphosphinic acids(DAPAs),i.e.dihexylphophinic acid(DHPA),di-(2,4,4-trimethylpentyl) phosphinic acid(DTMPPA)and didecylphophinic acid(DDPA),were synthesized through free radical addition reaction.The influence of the types of initiator,reation time and reaction temperature on the yield of DAPAs were investigated.The products were characterized by NMR and MS.By using DHPA,DTMPPA and DDPA(10%in kerosene)as extractants,the extraction of Co2 +and Ni2 +in sulphate medium at different equilibrium pH values were measured.The results show that the maximum yield of DHPA, DTMPPA and DDPA can all be achieved at about 130℃under the initiation of di-tert-butyl peroxide(DTBP).All the extraction of cobalt with respect to DHPA,DDPA and DTMPPA precedes that of nickel.The difference in pH1/2 value(defined as the pH at which 50%metal extraction occurs)between cobalt and nickel increases in the following sequence from large to small:DHPA,DDPA and DTMPPA,which indicates that the separation ability for cobalt and nickel ascends from DHPA,DDPA to DTMPPA.展开更多
The exploration of efficient bifunctional electrocatalysts for oxygen reduction reaction and oxygen evolution reaction is pivotal for the development of rechargeable metal–air batteries.Transition metal phosphides ar...The exploration of efficient bifunctional electrocatalysts for oxygen reduction reaction and oxygen evolution reaction is pivotal for the development of rechargeable metal–air batteries.Transition metal phosphides are emerging as promising catalyst candidates because of their superb activity and low cost.Herein,a novel metal phosphonate-derived cobalt/nickel phosphide@N-doped carbon hybrid was developed by a carbothermal reduction of cobalt/nickel phosphonate hybrids with different Co/Ni molar ratios.The metal phosphonate derivation method achieved an intimately coupled interaction between metal phosphides and a heteroatom-doped carbon substrate.The resultant Co_(2)P/Ni_(3)P@NC-0.2 enables an impressive electrocatalytic oxygen reduction reaction activity,comparable with those of state-of-the-art Pt/C catalysts in terms of onset potential(0.88 V),4e‒selectivity,methanol tolerance,and long-term durability.Moreover,remarkable oxygen evolution reaction activity was also observed in alkaline conditions.The high activity is ascribed to the N-doping,abundant accessible catalytic active sites,and the synergistic effect among the components.This work not only describes a highefficiency electrocatalyst for both oxygen reduction reaction and oxygen evolution reaction,but also highlights the application of metal phosphonate hybrids in fabricating metal phosphides with tunable structures,which is of great significance in the energy conversion field.展开更多
Mehlich 1(M1), mehlich 3(M3) and CaCl 2 DTPA have been used to predict the available micronutrient in soil. However, the forms of micronutrient extractable by these extractants are not known. In the present study, t...Mehlich 1(M1), mehlich 3(M3) and CaCl 2 DTPA have been used to predict the available micronutrient in soil. However, the forms of micronutrient extractable by these extractants are not known. In the present study, ten soils, collected from five provinces and the capital of China, representing a wide range of chemical and physical properties, were analyzed by sequential extraction to isolate five forms of cobalt and nickel, they are exchangeable, carbonate bound, Fe Mn oxide bound, organically bound and residual forms. The chemical forms extracted by M1, M3 and CaCl 2 DTPA were also investigated. The results show strong correlation between the carbonate bound or organically bound forms of Co or Ni and the amounts of extractable by any of the above three extractants. The main forms extracted by these extractants are carbonate and organically bound forms. The ranking of these three extractants for extraction of Co and Ni are M1>M3=CaCl 2 DTPA and M1=M3>CaCl 2 DTPA, respectively.展开更多
基金the National Key R&D Program of China(2017YFA 0208300 and 0700104)the National Natural Science Foundation of China(21671180)the State Key Laboratory of Organic Inorganic Composites(oic-201801007)。
文摘A low-cost,highly efficient and strong durable bifunctional electrocatalyst is crucial for electrochemical overall water splitting.In this paper,a self-templated strategy combined with in-situ phosphorization is applied to construct hollow structured bimetallic cobalt-nickel phosphide(CoNiP_(x))nanocages.Owing to their unique hollow structure and bimetallic synergistic effects,the as-synthesized CoNiP_(x)hollow nanocages exhibit a high electrocatalytic activity and stability towards hydrogen evolution reaction in all-pH electrolyte and a remarkable electrochemical performance for oxygen evolution reaction in 1.0 mol L^(-1)KOH.Meanwhile,with the bifunctional electrocatalyst in both anode and cathode for overall water splitting,a low voltage of 1.61 V and superior stability are achieved at a current density of 20 mA cm^(-2).
基金supported by the National Natural Science Foundation of China (NSFC, Nos. 21901222, U1904215 and 21671170)Lvyangjinfeng Talent Program of Yangzhou+2 种基金Top-notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP)Program for Young Chang Jiang Scholars of the Ministry of Education, China (No. Q2018270)Natural Science Foundation of Jiangsu Province (No. BK20200044)。
文摘Metal-organic frameworks(MOFs) as promising electrodes for supercapacitors are attracting increasing research interest. Herein, we report an effective strategy to improve the electrochemical performance of Ni-MOF for supercapacitor by introducing a secondary Co ion. The Co substitution of Ni in Ni-MOF can improve the intrinsic reactivity and stability. As a result, the bimetallic Co/Ni-MOF-1:15 with an optimal Co/Ni ratio delivers high specific capacitance(359 F/g at 0.5 A/g), good rate performance(81.5% retention at 5 A/g) and cycling stability(81% retention after 5000 cycles). These results demonstrate that the bimetallic synergistic strategy is an effective way to improve the pseudocapacitive performance of MOFs.
基金Projects(2007CB613506)supported by the National Basic Research Program of ChinaProjects(50674060,50734005)supported by the National Natural Science Foundation of China
文摘Three kinds of dialkylphosphinic acids(DAPAs),i.e.dihexylphophinic acid(DHPA),di-(2,4,4-trimethylpentyl) phosphinic acid(DTMPPA)and didecylphophinic acid(DDPA),were synthesized through free radical addition reaction.The influence of the types of initiator,reation time and reaction temperature on the yield of DAPAs were investigated.The products were characterized by NMR and MS.By using DHPA,DTMPPA and DDPA(10%in kerosene)as extractants,the extraction of Co2 +and Ni2 +in sulphate medium at different equilibrium pH values were measured.The results show that the maximum yield of DHPA, DTMPPA and DDPA can all be achieved at about 130℃under the initiation of di-tert-butyl peroxide(DTBP).All the extraction of cobalt with respect to DHPA,DDPA and DTMPPA precedes that of nickel.The difference in pH1/2 value(defined as the pH at which 50%metal extraction occurs)between cobalt and nickel increases in the following sequence from large to small:DHPA,DDPA and DTMPPA,which indicates that the separation ability for cobalt and nickel ascends from DHPA,DDPA to DTMPPA.
基金supported by the Natural Science Foundation of Shandong Province(ZR2019PB013)the Training Program of Innovation and Entrepreneurship for Undergraduates(CXCY2021161).
文摘The exploration of efficient bifunctional electrocatalysts for oxygen reduction reaction and oxygen evolution reaction is pivotal for the development of rechargeable metal–air batteries.Transition metal phosphides are emerging as promising catalyst candidates because of their superb activity and low cost.Herein,a novel metal phosphonate-derived cobalt/nickel phosphide@N-doped carbon hybrid was developed by a carbothermal reduction of cobalt/nickel phosphonate hybrids with different Co/Ni molar ratios.The metal phosphonate derivation method achieved an intimately coupled interaction between metal phosphides and a heteroatom-doped carbon substrate.The resultant Co_(2)P/Ni_(3)P@NC-0.2 enables an impressive electrocatalytic oxygen reduction reaction activity,comparable with those of state-of-the-art Pt/C catalysts in terms of onset potential(0.88 V),4e‒selectivity,methanol tolerance,and long-term durability.Moreover,remarkable oxygen evolution reaction activity was also observed in alkaline conditions.The high activity is ascribed to the N-doping,abundant accessible catalytic active sites,and the synergistic effect among the components.This work not only describes a highefficiency electrocatalyst for both oxygen reduction reaction and oxygen evolution reaction,but also highlights the application of metal phosphonate hybrids in fabricating metal phosphides with tunable structures,which is of great significance in the energy conversion field.
文摘Mehlich 1(M1), mehlich 3(M3) and CaCl 2 DTPA have been used to predict the available micronutrient in soil. However, the forms of micronutrient extractable by these extractants are not known. In the present study, ten soils, collected from five provinces and the capital of China, representing a wide range of chemical and physical properties, were analyzed by sequential extraction to isolate five forms of cobalt and nickel, they are exchangeable, carbonate bound, Fe Mn oxide bound, organically bound and residual forms. The chemical forms extracted by M1, M3 and CaCl 2 DTPA were also investigated. The results show strong correlation between the carbonate bound or organically bound forms of Co or Ni and the amounts of extractable by any of the above three extractants. The main forms extracted by these extractants are carbonate and organically bound forms. The ranking of these three extractants for extraction of Co and Ni are M1>M3=CaCl 2 DTPA and M1=M3>CaCl 2 DTPA, respectively.
