Electrochemical water splitting into hydrogen and oxygen is a promising strategy for future renewable energy conversion devices.The oxygen evolution reaction(OER)is considered as the bottleneck reaction in an overall ...Electrochemical water splitting into hydrogen and oxygen is a promising strategy for future renewable energy conversion devices.The oxygen evolution reaction(OER)is considered as the bottleneck reaction in an overall water splitting system because it involves 4e- and 4H+ transfer processes.Currently,it is highly desirable to explore low-cost alternative catalysts for OER at ambient conditions.Herein,we report for the first time that nickel phosphide(Ni2P)nanosheets can be facilely grown on Fe foam(FF)as an efficient electrocatalyst for OER with excellent durability and catalytic activity under alkaline conditions.To reach a current density of 10 m A/cm2,the Ni2P-FF catalyst required a low overpotential of only 198 mV for OER.The catalyst’s high OER activity and durability were well maintained at a high current density.The required overpotentials were only 267 and 313 mV to achieve the current densities of 100 and 300 m A/cm2,respectively.The combination of low-cost Fe foam with Ni2P provides a promising low-cost catalyst for large-scale application of electrocatalytic water splitting.展开更多
As global energy demand continues to rise with fossil fuels dwindling at a faster rate,posing energy and environmental concerns,there is a growing interest in exploring alternative,green,and renewable energy sources.A...As global energy demand continues to rise with fossil fuels dwindling at a faster rate,posing energy and environmental concerns,there is a growing interest in exploring alternative,green,and renewable energy sources.Ammonia is a key hydrogen energy carrier and precursor to many value-added products,and the efforts for its generation at commercial scale using greener methods are intensifying to mitigate the reliance on the energy-intensive Haber-Bosch process.The electrochemical nitrogen reduction reaction(e-NRR)is a highly promising way of synthesizing ammonia under energy-efficient,green,and ambient conditions.Despite its attractive potential,the activity and efficiency of conventional e-NRR catalysts are still a major concern due to low selectivity and poor ammonia yields.Inspired by the FeFe and FeV cofactors present in nitrogenases,this study reports the synthesis and electrocatalytic evaluation of FeVO_(4)catalyst for N_(2)reduction.The FeVO_(4)nanoparticles anchored on Fe foam(FF)could serve as an efficient electrocatalyst for the electrochemical nitrogen fixation,achieving a significant performance with highest NH_(3)yield of 22.5μg·h^(-1)·mg^(-1)and Faradaic efficiency(FE)of 20.74%at-0.2 VRHE in 0.1 M Na_(2)SO_(4).The FeVO_(4)electrocatalyst exhibited robust electrochemical stability for 24 h of operation at-0.2 VRHE.The high catalytic performance originated from the synergistic interactions between Fe and V which serve as dual electron donation centers for effective e-NRR.Furthermore,the coupling interaction between FeVO_(4)and FF support exposed abundant intrinsic active sites and facilitated beneficial charge transfer further inducing superior e-NRR activity.Density functional theory(DFT)computations disclosed that surface Fe atoms are the main active centers for e-NRR which proceed via the alternating pathway.展开更多
The research of superior water oxidation electrodes is essential for the green energy in the form of hydrogen by way of electrolytic water splitting, and still remains challenging. Based upon dealloying foam, Fe-Ni hy...The research of superior water oxidation electrodes is essential for the green energy in the form of hydrogen by way of electrolytic water splitting, and still remains challenging. Based upon dealloying foam, Fe-Ni hydroxide nanosheets network structure is designed on the surface of Fe-Ni alloy foam. The ratio of Ni/Fe elements was adjusted to realize the optimal catalytic activities for oxygen evolution reaction（OER） and hydrogen evolution reaction（HER）. The obtained electrode of Fe-Ni hydroxide nanosheets/Fe-Ni alloy foam-60% Fe（FN LDH/FNF-60, 60 is the percentage of Fe content） possess low overpotential of 261 mV to reach 10 mA/cm;, small Tafel slope（85.5 mV/dec）, and superior long-term stability（remaining 10 mA/cm;for over 14 h without attenuation） toward OER in 1.0 mol/L KOH.Moreover, an alkaline water electrolyzer is constructed with the FN LDH/FNF-60 as anode and Ni（OH）;/Fe-Ni alloy foam-25% Fe(Ni（OH）;/FNF-25) as cathode, which displays superior electrolytic performance（affording 10 mA/cm;at 1.62 V） and lasting durability.展开更多
Precursor foam based Co incorporated α-Fe<sub>2</sub>O<sub>3</sub> (AFC) was successfully synthesized at 600℃ calcination temperature by simple solution method using PVA. The formation of α-...Precursor foam based Co incorporated α-Fe<sub>2</sub>O<sub>3</sub> (AFC) was successfully synthesized at 600℃ calcination temperature by simple solution method using PVA. The formation of α-Fe<sub>2</sub>O<sub>3</sub> nanoparticles was confirmed by X-ray diffraction measurement and reduction in crystallite size was found after cobalt incorporation. Field emission scanning electron microscopy revealed the existence of pyramidal shaped iron oxide in AFC. FTIR and Raman spectra also confirmed the presence of α-Fe<sub>2</sub>O<sub>3</sub>. Photocatalytic activity study showed that the cobalt incorporated α-Fe<sub>2</sub>O<sub>3</sub> was better photocatalyst than pure α-Fe<sub>2</sub>O<sub>3</sub>. The cobalt incorporated iron oxide nanoparticles could be used for drug delivery application and this simple preparation method could be adopted for the synthesis of other transition metal oxides.展开更多
基金financially supported by the National Key Research and Development Program of China (2017YFA0402800)the National Natural Science Foundation of China (51772285)the National Synchrotron Radiation Laboratory at USTC.
文摘Electrochemical water splitting into hydrogen and oxygen is a promising strategy for future renewable energy conversion devices.The oxygen evolution reaction(OER)is considered as the bottleneck reaction in an overall water splitting system because it involves 4e- and 4H+ transfer processes.Currently,it is highly desirable to explore low-cost alternative catalysts for OER at ambient conditions.Herein,we report for the first time that nickel phosphide(Ni2P)nanosheets can be facilely grown on Fe foam(FF)as an efficient electrocatalyst for OER with excellent durability and catalytic activity under alkaline conditions.To reach a current density of 10 m A/cm2,the Ni2P-FF catalyst required a low overpotential of only 198 mV for OER.The catalyst’s high OER activity and durability were well maintained at a high current density.The required overpotentials were only 267 and 313 mV to achieve the current densities of 100 and 300 m A/cm2,respectively.The combination of low-cost Fe foam with Ni2P provides a promising low-cost catalyst for large-scale application of electrocatalytic water splitting.
基金supported by the Khalifa University of Science and Technology under the Advanced Materials Chemistry Center(AMCC).
文摘As global energy demand continues to rise with fossil fuels dwindling at a faster rate,posing energy and environmental concerns,there is a growing interest in exploring alternative,green,and renewable energy sources.Ammonia is a key hydrogen energy carrier and precursor to many value-added products,and the efforts for its generation at commercial scale using greener methods are intensifying to mitigate the reliance on the energy-intensive Haber-Bosch process.The electrochemical nitrogen reduction reaction(e-NRR)is a highly promising way of synthesizing ammonia under energy-efficient,green,and ambient conditions.Despite its attractive potential,the activity and efficiency of conventional e-NRR catalysts are still a major concern due to low selectivity and poor ammonia yields.Inspired by the FeFe and FeV cofactors present in nitrogenases,this study reports the synthesis and electrocatalytic evaluation of FeVO_(4)catalyst for N_(2)reduction.The FeVO_(4)nanoparticles anchored on Fe foam(FF)could serve as an efficient electrocatalyst for the electrochemical nitrogen fixation,achieving a significant performance with highest NH_(3)yield of 22.5μg·h^(-1)·mg^(-1)and Faradaic efficiency(FE)of 20.74%at-0.2 VRHE in 0.1 M Na_(2)SO_(4).The FeVO_(4)electrocatalyst exhibited robust electrochemical stability for 24 h of operation at-0.2 VRHE.The high catalytic performance originated from the synergistic interactions between Fe and V which serve as dual electron donation centers for effective e-NRR.Furthermore,the coupling interaction between FeVO_(4)and FF support exposed abundant intrinsic active sites and facilitated beneficial charge transfer further inducing superior e-NRR activity.Density functional theory(DFT)computations disclosed that surface Fe atoms are the main active centers for e-NRR which proceed via the alternating pathway.
基金supported by the Science and Technology Planning Project of Guangdong Province,China(No.2017B090916002)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(No.2016TQ03N541)+2 种基金Guangdong Natural Science Funds for Distinguished Young Scholar(No.2017B030306001)the National Natural Science Foundation of China(No.91745203)Guangdong Innovative and Entrepreneurial Research Team Program(No.2014ZT05N200)
文摘The research of superior water oxidation electrodes is essential for the green energy in the form of hydrogen by way of electrolytic water splitting, and still remains challenging. Based upon dealloying foam, Fe-Ni hydroxide nanosheets network structure is designed on the surface of Fe-Ni alloy foam. The ratio of Ni/Fe elements was adjusted to realize the optimal catalytic activities for oxygen evolution reaction（OER） and hydrogen evolution reaction（HER）. The obtained electrode of Fe-Ni hydroxide nanosheets/Fe-Ni alloy foam-60% Fe（FN LDH/FNF-60, 60 is the percentage of Fe content） possess low overpotential of 261 mV to reach 10 mA/cm;, small Tafel slope（85.5 mV/dec）, and superior long-term stability（remaining 10 mA/cm;for over 14 h without attenuation） toward OER in 1.0 mol/L KOH.Moreover, an alkaline water electrolyzer is constructed with the FN LDH/FNF-60 as anode and Ni（OH）;/Fe-Ni alloy foam-25% Fe(Ni（OH）;/FNF-25) as cathode, which displays superior electrolytic performance（affording 10 mA/cm;at 1.62 V） and lasting durability.
文摘Precursor foam based Co incorporated α-Fe<sub>2</sub>O<sub>3</sub> (AFC) was successfully synthesized at 600℃ calcination temperature by simple solution method using PVA. The formation of α-Fe<sub>2</sub>O<sub>3</sub> nanoparticles was confirmed by X-ray diffraction measurement and reduction in crystallite size was found after cobalt incorporation. Field emission scanning electron microscopy revealed the existence of pyramidal shaped iron oxide in AFC. FTIR and Raman spectra also confirmed the presence of α-Fe<sub>2</sub>O<sub>3</sub>. Photocatalytic activity study showed that the cobalt incorporated α-Fe<sub>2</sub>O<sub>3</sub> was better photocatalyst than pure α-Fe<sub>2</sub>O<sub>3</sub>. The cobalt incorporated iron oxide nanoparticles could be used for drug delivery application and this simple preparation method could be adopted for the synthesis of other transition metal oxides.
