Fe_(2)O_(3)nanorods and hexagonal nanoplates were synthesized and used as the promoters for Pt electrocatalysts toward the methanol oxidation reaction(MOR)in an alkaline electrolyte.The catalysts were characterized by...Fe_(2)O_(3)nanorods and hexagonal nanoplates were synthesized and used as the promoters for Pt electrocatalysts toward the methanol oxidation reaction(MOR)in an alkaline electrolyte.The catalysts were characterized by scanning electron microscopy,transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,cyclic voltammetry and chronoamperometry.The results show that the presence of Fe_(2)O_(3)in the electrocatalysts can promote the kinetic processes of MOR on Pt,and this promoting effect is related to the morphology of the Fe_(2)O_(3)promoter.The catalyst with Fe_(2)O_(3)nanorods as the promoter(Pt-Fe_(2)O_(3)/C-R)exhibits much higher catalytic activity and stability than that with Fe_(2)O_(3)nanoplates as the promoter(Pt-Fe_(2)O_(3)/C-P).The mass activity and specific activity of Pt in a Pt-Fe_(2)O_(3)/C-R catalyst are 5.32 A/mgpt and 162.7 A/m^2_(Pt),respectively,which are approximately 1.67 and 2.04 times those of the Pt-Fe_(2)O_(3)/C-P catalyst,and 4.19 and 6.16 times those of a commercial PtRu/C catalyst,respectively.Synergistic effects between Fe_(2)O_(3)and Pt and the high content of Pt oxides in the catalysts are responsible for the improvement.These findings contribute not only to our understanding of the MOR mechanism but also to the development of advanced electrocatalysts with high catalytic properties for direct methanol fuel cells.展开更多
NiO,an anodic electrochromic material,has applications in energy-saving windows,intelligent displays,and military camouflage.However,its electrochromic mechanism and reasons for its performance degradation in alkaline...NiO,an anodic electrochromic material,has applications in energy-saving windows,intelligent displays,and military camouflage.However,its electrochromic mechanism and reasons for its performance degradation in alkaline aqueous electrolytes are complex and poorly understood,making it challenging to improve NiO thin films.We studied the phases and electrochemical characteristics of NiO films in different states(initial,colored,bleached and after 8000 cycles)and identified three main reasons for performance degradation.First,Ni(OH)_(2)is generated during electrochromic cycling and deposited on the NiO film surface,gradually yielding a NiO@Ni(OH)_(2)core-shell structure,isolating the internal NiO film from the electrolyte,and preventing ion transfer.Second,the core-shell structure causes the mode of electrical conduction to change from first-to second-order conduction,reducing the efficiency of ion transfer to the surface Ni(OH)_(2)layer.Third,Ni(OH)_(2)and NiOOH,which have similar crystal structures but different b-axis lattice parameters,are formed during electrochromic cycling,and large volume changes in the unit cell reduce the structural stability of the thin film.Finally,we clarified the mechanism of electrochromic performance degradation of NiO films in alkaline aqueous electrolytes and provide a route to activation of NiO films,which will promote the development of electrochromic technology.展开更多
Cobalt sulfide (Co<sub>9</sub>S<sub>8</sub>) nanotubes were found to be an electrocatalyst for the hydrogen evolution reaction under alkaline condition. An electrode comprising of Co<sub>...Cobalt sulfide (Co<sub>9</sub>S<sub>8</sub>) nanotubes were found to be an electrocatalyst for the hydrogen evolution reaction under alkaline condition. An electrode comprising of Co<sub>9</sub>S<sub>8</sub> nanotubes on a glass carbon electrode (GCE) (mass loading: 0.855 mg·cm<sup>-2</sup>) produced a cathodic current density of 20 mA·cm<sup>-2</sup> at an overpotential of 320 mV. The Co<sub>9</sub>S<sub>8</sub>/GCE electrode was stable over 20,000 s during potentiostatic electrolysis. Minor degradation of reduction current after 4000 cyclic voltammetric sweeps suggests the long-term viability under operating conditions. The faradaic efficiency of Co<sub>9</sub>S<sub>8</sub> nanotubes is nearly 100% during the electrolysis of water.展开更多
Atomically dispersed Cu-based single-metal-site catalysts(Cu-N-C)have emerged as a frontier for electrocatalytic oxygen reduction reactions(ORR)because they can effectively optimize the D-band center of the Cu active ...Atomically dispersed Cu-based single-metal-site catalysts(Cu-N-C)have emerged as a frontier for electrocatalytic oxygen reduction reactions(ORR)because they can effectively optimize the D-band center of the Cu active site and provide appropriate adsorption/desorption energy for oxygen-containing intermediates.Metal-organic frameworks(MOFs)show excellent prospects in many fields because of their structural regularity and designability,but their direct use for electrocatalysis has been rarely reported due to the low intrinsic conductivity.Here,a MOF material(Cu-TCNQ)with highly regular single-atom copper active centers was successfully prepared using a solution chemical reaction method.Subsequently,Cu-TCNQ and graphene oxide(GO)were directly self-assembled to form a Cu-TCNQ/GO composite,which improved the conductivity of the catalyst while maintained the atomically precise controllability.The resistivity of the Cu-TCNQ/GO decreased by three orders of magnitude(1663.6-2.7 W/cm)compared with pure Cu-TCNQ.The half-wave potential was as high as 0.92 V in 0.1 mol/L KOH,even better than that of commercial 20%Pt/C.In alkaline polymer electrolyte fuel cells(APEFCs),the open-circuit voltage and power density of Cu-TCNQ/GO electrode reached 0.95 V and 320 m W/cm^(2),respectively,which suggests that Cu-TCNQ/GO has a good potential for application as a cathode ORR catalyst.展开更多
The severe dendrite growth on zinc anode in alkaline electrolyte brings great challenge to the development of zinc-based batteries.It is a simple and effective strategy to inhibit zinc dendrite formation by introducin...The severe dendrite growth on zinc anode in alkaline electrolyte brings great challenge to the development of zinc-based batteries.It is a simple and effective strategy to inhibit zinc dendrite formation by introducing additives into the electrolyte.In this study,N,S-doped carbon dots(TU-CQDs)were synthesized and used as additives to regulate zinc deposition in a typical KOH electrolyte.The experimental and three-dimensional transient nucleation model disclosed that the special functional groups of carbon dots can change the electrode surface state and the coordination behaviors of zinc species in the electrolyte.Therefore,TU-CQDs can not only inhibit the hydrogen evolution reaction,but also achieve uniform zinc deposition.The in-situ synchrotron radiation X-ray imaging elucidated that TU-CQDs can effectively inhibit the dendrite growth and improve the reversibility of zinc plating/stripping process.This work provides a feasible route for regulating the reversibility of zinc metal anode in alkaline electrolyte.展开更多
Polyvinyl alcohol （PVA）-sodium polyacrylate （PAAS）-KOH-H2O alkaline polymer electrolyte film with high ionic conductivity was prepared by a solution-casting method. Polymer Ni（OH）2/activated carbon （AC） hybrid...Polyvinyl alcohol （PVA）-sodium polyacrylate （PAAS）-KOH-H2O alkaline polymer electrolyte film with high ionic conductivity was prepared by a solution-casting method. Polymer Ni（OH）2/activated carbon （AC） hybrid supercapacitors with different electrode active material mass ratios （positive to negative） were fabricated using this alkaline polymer electrolyte, nickel hydroxide positive electrodes, and AC negative electrodes. Galvanostatic charge/ discharge and electrochemical impedance spectroscopy （EIS） methods were used to study the electrochemical performance of the capacitors, such as charge/discharge specific capacitance, rate charge/discharge ability, and charge/discharge cyclic stability. Experimental results showed that with the decreasing of active material mass ratio m（Ni（OH）2）/m（AC）, the charge/discharge specific capacitance increases, but the rate charge/discharge ability and the charge/discharge cyclic stability decrease.展开更多
Hydrogel-based quasi-solid-state electrolytes(Q-SSEs) swollen with electrolyte solutions are important components in stretchable supercapacitors and other wearable devices. This work fabricates a supertough, fatigue-r...Hydrogel-based quasi-solid-state electrolytes(Q-SSEs) swollen with electrolyte solutions are important components in stretchable supercapacitors and other wearable devices. This work fabricates a supertough, fatigue-resistant, and alkali-resistant multi-bond network(MBN) hydrogel aiming to be an alkaline Q-SSE. To synthesize the hydrogel, a 2-ureido-4[1H]-pyrimidone(UPy) motif is introduced into a poly(acrylic acid) polymer chain. The obtained MBN hydrogels with 75 wt% water content exhibit tensile strength as high as 2.47 MPa, which is enabled by the large energy dissipation ability originated from the dissociation of UPy dimers due to their high bond association energy. Owing to the high dimerization constant of UPy motifs, the dissociated UPy motifs are able to partially re-associate soon after being released from external forces, resulting in excellent fatigue-resistance. More importantly, the MBN hydrogels exhibit excellent alkali-resistance ability. The UPy Gel-10 swollen with 1 mol/L KOH display a tensile strength as high as ~1.0 MPa with elongation at break of ~550%. At the same time, they show ionic conductivity of ~17 m S/cm, which do not decline even when the hydrogels are stretched to 500% strain.The excellent mechanical property and ionic conductivity of the present hydrogels demonstrate potential application as a stretchable alkaline Q-SSE.展开更多
Aqueous alkaline zinc batteries have received widespread attention owing to its higher electrode potential and faster reaction kinetics compared to in mild aqueous electrolyte.However,Zn metal anode in alkaline electr...Aqueous alkaline zinc batteries have received widespread attention owing to its higher electrode potential and faster reaction kinetics compared to in mild aqueous electrolyte.However,Zn metal anode in alkaline electrolyte usually suffers more severe corrosion,passivation,and hydrogen evolution reaction.Herein,an interface chemical regulation strategy employs to in-situ construct a Zn-Sn alloy layer during cycling.The K_(2)[Sn(OH)_(6)]has been introduced into the electrolyte as the deposition overpotential of Zn and Sn in alkaline electrolyte is approximate leading to their simultaneously plating.The Zn-Sn alloy layer not only prevents Zn anode corrosion and suppresses the dendrite growth but also promotes the reaction kinetics.Therefore,the Zn||Zn cell exhibits a long life of 400 h in alkaline electrolyte about 20 times of that in without K_(2)[Sn(OH)_(6)]electrolyte.Moreover,the N-NCP@PQ_(x)||Zn full cell displays a superior cycle performance of 4000 cycles with 93%capacity retention at 2 A/g.展开更多
Common anode materials in aqueous alkaline electrolytes,such as cadmium,metal hydrides and zinc,usually suffer from remarkable biotoxicity,high cost,and serious side reactions.To overcome these problems,we develop a c...Common anode materials in aqueous alkaline electrolytes,such as cadmium,metal hydrides and zinc,usually suffer from remarkable biotoxicity,high cost,and serious side reactions.To overcome these problems,we develop a conjugated porous polymer(CPP)in-situ grown on reduced graphene oxide(rGO)and Ketjen black(KB),noted as C_(4)N/rGO and C_(4)N/KB respectively,as the alternative anodes.The results show that C_(4)N/rGO electrode delivers a low redox potential(−0.905 V vs.Ag/AgCl),high specific capacity(268.8 mAh g^(-1) at 0.2 A g^(-1)),ultra-stable and fast sodium ion storage behavior(216 mAh g^(-1) at 20 A g^(-1))in 2 M NaOH electrolyte.The assembled C_(4)N/rGO//Ni(OH)_(2) full battery can cycle stably more than 38,000 cycles.Furthermore,by adding a small amount of antifreeze additive dimethyl sulfoxide(DMSO)to adjust the hydrogen bonding network,the low-temperature performance of the electrolyte(0.1 DMSO/2 M NaOH)is significantly improved while hydrogen evolution is inhibited.Consequently,the C_(4)N/rGO//Ni(OH)_(2) full cell exhibits an energy density of 147.3 Wh Kg^(-1) and ultra-high cycling stability over a wide temperature range from−70 to 45℃.This work provides an ultra-stable high-capacity CPPbased anode and antifreeze electrolyte for aqueous alkaline batteries and will facilitate their practical applications under extreme conditions.展开更多
The development of highly efficient electrocatalysts toward hydrogen oxidation reaction(HOR)under alkaline media is essential for the commercialization of alkaline exchange membrane fuel cells(AEMFCs).However,the HOR ...The development of highly efficient electrocatalysts toward hydrogen oxidation reaction(HOR)under alkaline media is essential for the commercialization of alkaline exchange membrane fuel cells(AEMFCs).However,the HOR kinetics in alkaline is two to three orders of magnitude slower than that in acid.More critically,fundamental understanding of the sluggish kinetics derived from the p H effect is still debatable.In this review,the recent development of understanding HOR mechanism and rational design of advanced HOR electrocatalysts are summarized.First,recent advances in the theories focusing on fundamental understandings of HOR under alkaline electrolyte are comprehensively discussed.Then,from the aspect of intermediates binding energy,optimizing hydrogen binding energy(HBE)and increasing hydroxyl binding energy(OHBE),the strategies for designing efficient alkaline HOR catalysts are summarized.At last,perspectives for the future research on alkaline HOR are pointed out.展开更多
Anion exchange membrane(AEM)fuel cells have gained great attention partially due to the advantage of using non-precious metal as catalysts.However,the reaction kinetics of hydrogen oxidation reaction(HOR)is two orders...Anion exchange membrane(AEM)fuel cells have gained great attention partially due to the advantage of using non-precious metal as catalysts.However,the reaction kinetics of hydrogen oxidation reaction(HOR)is two orders of magnitude slower in alkaline systems than in acid.To understand the slower kinetics of HOR in base,two major theories have been proposed,such as(1)pH dependent hydrogen binding energy as a major descriptor for HOR;and(2)bifunctional theory based on the contributions of both hydrogen and hydroxide adsorption for HOR in alkaline electrolyte.Here,we discuss the possible HOR mechanisms in alkaline electrolytes with the corresponding change in their Tafel behavior.Apart from the traditional Tafel-Volmer and Heyrovsky-Volmer HOR mechanisms,the recently proposed hydroxide adsorption step is also discussed to illustrate the difference in HOR mechanisms in acid and base.We further summarize the representative works of alkaline HOR catalyst design(e.g.,precious metals,alloy,intermetallic materials,Ni-based alloys,carbides,nitrides,etc.),and briefly describe their fundamental HOR reaction mechanism to emphasize the difference in elementary reaction steps in alkaline medium.The strategy of strengthening local interaction that facilitates both H2 desorption and Hads+OHads recombination is finally proposed for future HOR catalyst design in alkaline environment.展开更多
Electrochemical water splitting powered by renewables-generated electricity represents a promising approach for green hydrogen production.However,the sluggish kinetics for the hydrogen evolution reaction(HER)under an ...Electrochemical water splitting powered by renewables-generated electricity represents a promising approach for green hydrogen production.However,the sluggish kinetics for the hydrogen evolution reaction(HER)under an alkaline medium causes a massive amount of energy losses,hindering large-scale production.Exploring efficient and low-cost catalyst candidates for large-scale H_(2) generation becomes a crucial demand.Single-atom catalysts(SACs)demonstrate great promise for enabling efficient alkaline HER catalysis at maximum atom utilization efficiency.In this review,we provide a comprehensive overview of the recent progress in SACs for the HER application in alkaline environments.The fundamentals of alkaline HER are first introduced,followed by a justification of the need to develop SACs.The rational design of the SACs including the inherent element property,coordination environment,SAC morphology,and SAC mass loading are highlighted.To facilitate the development of SACs for alkaline HER,we further propose the remaining challenges and perspectives in this research field.展开更多
This work demonstrates the outstanding performance of alloyed Au1 Pt1 nanoparticles on hydrogen oxidation reaction(HOR)in alkaline solution.Due to the weakened hydrogen binding energy caused by uniform incorporation o...This work demonstrates the outstanding performance of alloyed Au1 Pt1 nanoparticles on hydrogen oxidation reaction(HOR)in alkaline solution.Due to the weakened hydrogen binding energy caused by uniform incorporation of Au,the alloyed Au1Pt1/C nanoparticles exhibit superior HOR activity than commercial PtRu/C.On the contrary,the catalytic performance of the phase-segregated Au2Pt1/C and Au1Pt1/C bimetallic nanoparticles in HOR is significantly worse.Moreover,Au1Pt1/C shows a remarkable durability with activity dropping only 4% after 3000 CV cycles,while performance attenuation of commercial PtRu/C is high up to 15% under the same condition.Our results indicate that the alloyed Au1Pt1/C is a promising candidate to substitute commercial PtRu/C for hydrogen oxidation reaction in alkaline electrolyte.展开更多
A series of NiMoO_(4)-nano rod/carbon cloth composite electrodes with different loadings(x)of NiMoO_(4)-NRs was synthesized with a view to implementing an efficient hydrogen evolution reaction(HER).The NiMoO_(4) nano-...A series of NiMoO_(4)-nano rod/carbon cloth composite electrodes with different loadings(x)of NiMoO_(4)-NRs was synthesized with a view to implementing an efficient hydrogen evolution reaction(HER).The NiMoO_(4) nano-rods(NRs)were prepared by growing them directly on carbon cloth(CC)via a simple hydrothermal reaction coupled with an annealing treatment.The resulting NiMoO_(4)-NR/CC-x composites served directly as electrodes for electrolysis of an alkaline medium and a simulated sea water.The results indicated that among the NiMoO_(4)-NR/CC-x composites,the NiMoO_(4)-NR/CC-10 composite possessed the highest HER activity with an overpotential of 244.8 mV at 10 mA/cm^(2),a Tafel slope of 95 mV/dec,the fastest charge transfer rate(R_(ct)<1Ω)and good stability in alkaline media.Even in simulated seawater,the NiMoO_(4)-NR/CC-10 composite showed good stability.The outstanding HER activity and stability may originate from the strong interaction between Ni and Mo in the NiMoO_(4) NRs as well as the efficient charge transfer process and the rate of the HER due to the synergistic effect involving the CC and NiMoO_(4) NRs.展开更多
The search for active,stable,and cost-effective electrocatalysts for hydrogen evolution reaction(HER)is desirable,but it remains a great challenge in the overall water splitting.Here,we report the synthesis of nickel ...The search for active,stable,and cost-effective electrocatalysts for hydrogen evolution reaction(HER)is desirable,but it remains a great challenge in the overall water splitting.Here,we report the synthesis of nickel boron nanoparticles supported on Vulcan carbon(Ni-B)via a simple,yet scalable,two-step chemical reduction–annealing strategy.The results of the electrochemical measurements suggest that the overpotentials of Ni-B-400 are 114 and 215 mV(in 1 mol L^–1 KOH)at current densities of 10 and 40 mA cm^?2,respectively,indicating an exceedingly good electrocatalytic activity in the HER.More importantly,Ni-B maintains a current density of 7.6 mA cm^-2 at an overpotential of 0.15 V for 20 h in the durability test.The excellent HER activity of Ni-B-400 is derived from the small particle size and the expanded lattice of Ni,which can optimize the hydrogen absorption energy and enhance the electrocatalytic properties.展开更多
Plasma electrolytic oxidation （PEO） is carried out on 6061 Al-alloys in a weak alkaline electrolyte containing NaOH, Na2SiO3 and NaCl. Centered on the correlation of composition and structure, analyses by means of X...Plasma electrolytic oxidation （PEO） is carried out on 6061 Al-alloys in a weak alkaline electrolyte containing NaOH, Na2SiO3 and NaCl. Centered on the correlation of composition and structure, analyses by means of X-ray diffration （XRD）, scanning electron microscope （SEM） and energy dispersive spectrometry （EDS） are conducted on the specimens, which have been PEO-treated under hybrid voltages of different direct current （DC） values （140-280 V） with constant alternate current （AC） amplitude （200 V）. Attention is paid to the composition, properties and growth mechanism of oxide layers formed with hybrid voltages. Moreover, the main effects of DC value are discussed. Ceramic layers with a double-layer structure which combines hard outer and soft inner layers are found to be consist of α-Al2O3,γ-Al2O3 and mullite. With the DC values increasing, the growth of the ceramic layers tends to have increasingly obvious three-stage feature.展开更多
The anion exchange membrane fuel cell(AEMFC)enables the use of non-noble metal catalysts,greatly reducing the cost of fuel cells.Nickel-based materials are considered the most promising anode catalysts for practical a...The anion exchange membrane fuel cell(AEMFC)enables the use of non-noble metal catalysts,greatly reducing the cost of fuel cells.Nickel-based materials are considered the most promising anode catalysts for practical applications in low-cost AEMFCs,but designing Ni-based catalysts with breakthrough performance remains a major challenge due to the slow kinetics of the anodic hydrogen oxidation reaction(HOR)in alkaline media.In this review,the electrocatalytic mechanisms of the alkaline HOR and the rigorous methods for assessing the performance of Ni-based catalysts are presented as the cornerstones for designing Ni-based catalysts.Alignment with the modulated geometric and electronic properties of Ni-based catalysts is thoroughly discussed,based on the principles of mechanism and performance evaluation.An element navigation map is presented to guide the precise design of efficient Ni-based non-noble metal catalysts for the alkaline HOR,and the current challenges and future prospects are outlined to provide valuable directions for new research about the alkaline HOR on Ni.This review not only offers insights into the rational design of Ni-based electrocatalysts but also provides a blueprint for the commercialization of cost-effective AEMFCs.展开更多
Nickel/cobalt-based materials are promising cathodes owing to the high redox potential,high specific capacity,and long cycling performance.However,with the mass-loading of the electrode increasing,it greatly hinders t...Nickel/cobalt-based materials are promising cathodes owing to the high redox potential,high specific capacity,and long cycling performance.However,with the mass-loading of the electrode increasing,it greatly hinders the ion diffusion and charge transport,resulting in serious decrease of the electrode capacity.Herein,a hierarchical nickel-cobalt-based porous nanoflower structure(NiCo-Nanoflower)composed of numerous ultrathin nanosheets is synthesized,which significantly enhances the surface area and provides additional active sites.Besides,the abundant oxygen defects in NiCo-Nanoflower significantly enhance its electrical conductivity.Therefore,the NiCo-Nanoflower electrode exhibits a high reversible capacity of up to 210.4 mAh g^(−1)at 0.5 A g^(−1)and excellent rate retention of 180.4 mAh g^(−1)at 8 A g^(−1)(104 mA cm^(−2))even under high areal mass loading of 13 mg cm^(−2).Upon assembly in a NiCo//Zn battery system,the configuration demonstrates exceptional electrochemical stability,maintaining 74.3%capacity retention after 5000 cycles.This work demonstrates that NiCo-Nanoflower,equipped with three-dimensional microstructure and oxygen-enriched defects,holds significant potential for application in high-mass-loading cathodes for alkaline aqueous zinc batteries.展开更多
An environmentally friendly precursor, adenosine, has been used as a dual source of C and N to synthesize nitrogen-doped carbon catalyst with/without Fe. A hydrothermal carbonization method has been used and water is ...An environmentally friendly precursor, adenosine, has been used as a dual source of C and N to synthesize nitrogen-doped carbon catalyst with/without Fe. A hydrothermal carbonization method has been used and water is the carbonization media. The morphology of samples with/without Fe component has been compared by HRTEM, and the result shows that Fe can promote the graphitization of carbon. Further electro-chemical test shows that the oxygen reduction reaction（ORR） catalytic activity of Fe-containing sample（C–Fe N） is much higher than that of the Fe-free sample（C–N）. Additionally, the intermediates of C–Fe N formed during each synthetic procedure have been thoroughly characterized by multiple methods,and the function of each procedure has been discussed. The C–Fe N sample exhibits high electro-catalytic stability and superior electro-catalytic activity toward ORR in alkaline media, with its half-wave potential 20 mV lower than that of commercial Pt/C（40 wt%）. It is further incorporated into alkaline polymer electrolyte fuel cell（APEFC） as the cathode material and led to a power density of 100 m W/cm;.展开更多
Electrocatalytic reduction of nitrate(NO_(3)^(−))and nitride(NO_(2)^(−))to ammonia(NH3)is of wide interest as a promising alternative to the energy-intensive Haber-Bosch route for mitigating the vast energy consumptio...Electrocatalytic reduction of nitrate(NO_(3)^(−))and nitride(NO_(2)^(−))to ammonia(NH3)is of wide interest as a promising alternative to the energy-intensive Haber-Bosch route for mitigating the vast energy consumption and the accompanied carbon dioxide emission,as well as benefiting for the relevant sewage treatment.However,exploring an efficient and low-cost catalyst with high atomic utilization that can effectively facilitate the slow multi-electron transfer process remains a grand challenge.Herein,we present an efficient hydrogenation of NO_(3)^(−)/NO_(2)^(−)species to NH3 in both alkaline and neutral environments over the Fe_(2)(MoO_(4))_(3)derived hybrid electrocatalyst with the metallic Fe site on FeMoO_(4)(Fe/FeMoO_(4)).The Mo ingredient can play a synergistically positive role in further promoting the NH_(3) production on Fe.As a result,Fe/FeMoO_(4)behaves well in the electrochemical NH_(3) generation from NO_(2)^(−)with a maximum NH_(3) Faradaic efficiency(FE)of 96.53%and 87.68%in alkaline and neutral electrolyte,corresponding to the NH_(3) yield rate of 640.68 and 302.56 mg·h^(−1)·mg_(cat.)^(−1),respectively,which outperforms the Fe and Mo counterpart and other similar catalyst,showing the robust catalytic capacity of each active site.展开更多
文摘Fe_(2)O_(3)nanorods and hexagonal nanoplates were synthesized and used as the promoters for Pt electrocatalysts toward the methanol oxidation reaction(MOR)in an alkaline electrolyte.The catalysts were characterized by scanning electron microscopy,transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,cyclic voltammetry and chronoamperometry.The results show that the presence of Fe_(2)O_(3)in the electrocatalysts can promote the kinetic processes of MOR on Pt,and this promoting effect is related to the morphology of the Fe_(2)O_(3)promoter.The catalyst with Fe_(2)O_(3)nanorods as the promoter(Pt-Fe_(2)O_(3)/C-R)exhibits much higher catalytic activity and stability than that with Fe_(2)O_(3)nanoplates as the promoter(Pt-Fe_(2)O_(3)/C-P).The mass activity and specific activity of Pt in a Pt-Fe_(2)O_(3)/C-R catalyst are 5.32 A/mgpt and 162.7 A/m^2_(Pt),respectively,which are approximately 1.67 and 2.04 times those of the Pt-Fe_(2)O_(3)/C-P catalyst,and 4.19 and 6.16 times those of a commercial PtRu/C catalyst,respectively.Synergistic effects between Fe_(2)O_(3)and Pt and the high content of Pt oxides in the catalysts are responsible for the improvement.These findings contribute not only to our understanding of the MOR mechanism but also to the development of advanced electrocatalysts with high catalytic properties for direct methanol fuel cells.
基金supported by the Special Support Program for High-level Talents of Shaanxi Province(No.2020-44)Innnovative Talent Project of China and The Youth Innovation Team of Shaanxi Universities
文摘NiO,an anodic electrochromic material,has applications in energy-saving windows,intelligent displays,and military camouflage.However,its electrochromic mechanism and reasons for its performance degradation in alkaline aqueous electrolytes are complex and poorly understood,making it challenging to improve NiO thin films.We studied the phases and electrochemical characteristics of NiO films in different states(initial,colored,bleached and after 8000 cycles)and identified three main reasons for performance degradation.First,Ni(OH)_(2)is generated during electrochromic cycling and deposited on the NiO film surface,gradually yielding a NiO@Ni(OH)_(2)core-shell structure,isolating the internal NiO film from the electrolyte,and preventing ion transfer.Second,the core-shell structure causes the mode of electrical conduction to change from first-to second-order conduction,reducing the efficiency of ion transfer to the surface Ni(OH)_(2)layer.Third,Ni(OH)_(2)and NiOOH,which have similar crystal structures but different b-axis lattice parameters,are formed during electrochromic cycling,and large volume changes in the unit cell reduce the structural stability of the thin film.Finally,we clarified the mechanism of electrochromic performance degradation of NiO films in alkaline aqueous electrolytes and provide a route to activation of NiO films,which will promote the development of electrochromic technology.
文摘Cobalt sulfide (Co<sub>9</sub>S<sub>8</sub>) nanotubes were found to be an electrocatalyst for the hydrogen evolution reaction under alkaline condition. An electrode comprising of Co<sub>9</sub>S<sub>8</sub> nanotubes on a glass carbon electrode (GCE) (mass loading: 0.855 mg·cm<sup>-2</sup>) produced a cathodic current density of 20 mA·cm<sup>-2</sup> at an overpotential of 320 mV. The Co<sub>9</sub>S<sub>8</sub>/GCE electrode was stable over 20,000 s during potentiostatic electrolysis. Minor degradation of reduction current after 4000 cyclic voltammetric sweeps suggests the long-term viability under operating conditions. The faradaic efficiency of Co<sub>9</sub>S<sub>8</sub> nanotubes is nearly 100% during the electrolysis of water.
基金supported by the National Key Research and Development Program of China(No.2022YFB3807500)the National Natural Science Foundation of China(No.22220102003)+1 种基金the Beijing Natural Science Foundation(No.JL23003)“Double-First-Class”construction projects(Nos.XK180301 and XK1804-02)。
文摘Atomically dispersed Cu-based single-metal-site catalysts(Cu-N-C)have emerged as a frontier for electrocatalytic oxygen reduction reactions(ORR)because they can effectively optimize the D-band center of the Cu active site and provide appropriate adsorption/desorption energy for oxygen-containing intermediates.Metal-organic frameworks(MOFs)show excellent prospects in many fields because of their structural regularity and designability,but their direct use for electrocatalysis has been rarely reported due to the low intrinsic conductivity.Here,a MOF material(Cu-TCNQ)with highly regular single-atom copper active centers was successfully prepared using a solution chemical reaction method.Subsequently,Cu-TCNQ and graphene oxide(GO)were directly self-assembled to form a Cu-TCNQ/GO composite,which improved the conductivity of the catalyst while maintained the atomically precise controllability.The resistivity of the Cu-TCNQ/GO decreased by three orders of magnitude(1663.6-2.7 W/cm)compared with pure Cu-TCNQ.The half-wave potential was as high as 0.92 V in 0.1 mol/L KOH,even better than that of commercial 20%Pt/C.In alkaline polymer electrolyte fuel cells(APEFCs),the open-circuit voltage and power density of Cu-TCNQ/GO electrode reached 0.95 V and 320 m W/cm^(2),respectively,which suggests that Cu-TCNQ/GO has a good potential for application as a cathode ORR catalyst.
基金financially supported by the National Key Research and Development Program of China(No.2019YFC1907801)Innovation-Driven Project of Central South University(No.2020CX007).
文摘The severe dendrite growth on zinc anode in alkaline electrolyte brings great challenge to the development of zinc-based batteries.It is a simple and effective strategy to inhibit zinc dendrite formation by introducing additives into the electrolyte.In this study,N,S-doped carbon dots(TU-CQDs)were synthesized and used as additives to regulate zinc deposition in a typical KOH electrolyte.The experimental and three-dimensional transient nucleation model disclosed that the special functional groups of carbon dots can change the electrode surface state and the coordination behaviors of zinc species in the electrolyte.Therefore,TU-CQDs can not only inhibit the hydrogen evolution reaction,but also achieve uniform zinc deposition.The in-situ synchrotron radiation X-ray imaging elucidated that TU-CQDs can effectively inhibit the dendrite growth and improve the reversibility of zinc plating/stripping process.This work provides a feasible route for regulating the reversibility of zinc metal anode in alkaline electrolyte.
基金Supported by Leading Academic Discipline Project of Shanghai Municipal Education Commission (J50102)
文摘Polyvinyl alcohol （PVA）-sodium polyacrylate （PAAS）-KOH-H2O alkaline polymer electrolyte film with high ionic conductivity was prepared by a solution-casting method. Polymer Ni（OH）2/activated carbon （AC） hybrid supercapacitors with different electrode active material mass ratios （positive to negative） were fabricated using this alkaline polymer electrolyte, nickel hydroxide positive electrodes, and AC negative electrodes. Galvanostatic charge/ discharge and electrochemical impedance spectroscopy （EIS） methods were used to study the electrochemical performance of the capacitors, such as charge/discharge specific capacitance, rate charge/discharge ability, and charge/discharge cyclic stability. Experimental results showed that with the decreasing of active material mass ratio m（Ni（OH）2）/m（AC）, the charge/discharge specific capacitance increases, but the rate charge/discharge ability and the charge/discharge cyclic stability decrease.
基金the National Natural Science Foundation of China (Nos. 21774069, 51633003 and 21474058) for financial support。
文摘Hydrogel-based quasi-solid-state electrolytes(Q-SSEs) swollen with electrolyte solutions are important components in stretchable supercapacitors and other wearable devices. This work fabricates a supertough, fatigue-resistant, and alkali-resistant multi-bond network(MBN) hydrogel aiming to be an alkaline Q-SSE. To synthesize the hydrogel, a 2-ureido-4[1H]-pyrimidone(UPy) motif is introduced into a poly(acrylic acid) polymer chain. The obtained MBN hydrogels with 75 wt% water content exhibit tensile strength as high as 2.47 MPa, which is enabled by the large energy dissipation ability originated from the dissociation of UPy dimers due to their high bond association energy. Owing to the high dimerization constant of UPy motifs, the dissociated UPy motifs are able to partially re-associate soon after being released from external forces, resulting in excellent fatigue-resistance. More importantly, the MBN hydrogels exhibit excellent alkali-resistance ability. The UPy Gel-10 swollen with 1 mol/L KOH display a tensile strength as high as ~1.0 MPa with elongation at break of ~550%. At the same time, they show ionic conductivity of ~17 m S/cm, which do not decline even when the hydrogels are stretched to 500% strain.The excellent mechanical property and ionic conductivity of the present hydrogels demonstrate potential application as a stretchable alkaline Q-SSE.
基金supported by Joint Funds of the National Natural Science Foundation of China(No.U22A20140)University of Jinan Disciplinary Cross-Convergence Construction Project 2023(No.XKJC-202309)+3 种基金Jinan City-School Integration Development Strategy Project(No.JNSX2023015)Independent Cultivation Program of Innovation Team of Ji’nan City(No.202333042)the Youth Innovation Group Plan of Shandong Province(No.2022KJ095)Special thanks to the Optical microscopy(Yuescope,YM710R).
文摘Aqueous alkaline zinc batteries have received widespread attention owing to its higher electrode potential and faster reaction kinetics compared to in mild aqueous electrolyte.However,Zn metal anode in alkaline electrolyte usually suffers more severe corrosion,passivation,and hydrogen evolution reaction.Herein,an interface chemical regulation strategy employs to in-situ construct a Zn-Sn alloy layer during cycling.The K_(2)[Sn(OH)_(6)]has been introduced into the electrolyte as the deposition overpotential of Zn and Sn in alkaline electrolyte is approximate leading to their simultaneously plating.The Zn-Sn alloy layer not only prevents Zn anode corrosion and suppresses the dendrite growth but also promotes the reaction kinetics.Therefore,the Zn||Zn cell exhibits a long life of 400 h in alkaline electrolyte about 20 times of that in without K_(2)[Sn(OH)_(6)]electrolyte.Moreover,the N-NCP@PQ_(x)||Zn full cell displays a superior cycle performance of 4000 cycles with 93%capacity retention at 2 A/g.
基金financial support by the National Natural Science Foundation of China(22371010,21771017 and 51702009)the“Hundred Talents Program”of the Chinese Academy of Science,Fundamental Research Funds for the Central Universities,Shenzhen Science and Technology Program(JCYJ20210324115412035 JCYJ2021-0324123202008,JCYJ20210324122803009 and ZDSYS20210813095534001)Guangdong Basic and Applied Basic Research Foundation(2021A1515110880).
文摘Common anode materials in aqueous alkaline electrolytes,such as cadmium,metal hydrides and zinc,usually suffer from remarkable biotoxicity,high cost,and serious side reactions.To overcome these problems,we develop a conjugated porous polymer(CPP)in-situ grown on reduced graphene oxide(rGO)and Ketjen black(KB),noted as C_(4)N/rGO and C_(4)N/KB respectively,as the alternative anodes.The results show that C_(4)N/rGO electrode delivers a low redox potential(−0.905 V vs.Ag/AgCl),high specific capacity(268.8 mAh g^(-1) at 0.2 A g^(-1)),ultra-stable and fast sodium ion storage behavior(216 mAh g^(-1) at 20 A g^(-1))in 2 M NaOH electrolyte.The assembled C_(4)N/rGO//Ni(OH)_(2) full battery can cycle stably more than 38,000 cycles.Furthermore,by adding a small amount of antifreeze additive dimethyl sulfoxide(DMSO)to adjust the hydrogen bonding network,the low-temperature performance of the electrolyte(0.1 DMSO/2 M NaOH)is significantly improved while hydrogen evolution is inhibited.Consequently,the C_(4)N/rGO//Ni(OH)_(2) full cell exhibits an energy density of 147.3 Wh Kg^(-1) and ultra-high cycling stability over a wide temperature range from−70 to 45℃.This work provides an ultra-stable high-capacity CPPbased anode and antifreeze electrolyte for aqueous alkaline batteries and will facilitate their practical applications under extreme conditions.
基金financially supported by the National Key Research and Development program of China(2018YFB1502302)the National Natural Science Foundation of China(21972107)+1 种基金the Natural Science Foundation of Hubei Province(2020CFA095)the Natural Science Foundation of Jiangsu Province(BK20191186)。
文摘The development of highly efficient electrocatalysts toward hydrogen oxidation reaction(HOR)under alkaline media is essential for the commercialization of alkaline exchange membrane fuel cells(AEMFCs).However,the HOR kinetics in alkaline is two to three orders of magnitude slower than that in acid.More critically,fundamental understanding of the sluggish kinetics derived from the p H effect is still debatable.In this review,the recent development of understanding HOR mechanism and rational design of advanced HOR electrocatalysts are summarized.First,recent advances in the theories focusing on fundamental understandings of HOR under alkaline electrolyte are comprehensively discussed.Then,from the aspect of intermediates binding energy,optimizing hydrogen binding energy(HBE)and increasing hydroxyl binding energy(OHBE),the strategies for designing efficient alkaline HOR catalysts are summarized.At last,perspectives for the future research on alkaline HOR are pointed out.
文摘Anion exchange membrane(AEM)fuel cells have gained great attention partially due to the advantage of using non-precious metal as catalysts.However,the reaction kinetics of hydrogen oxidation reaction(HOR)is two orders of magnitude slower in alkaline systems than in acid.To understand the slower kinetics of HOR in base,two major theories have been proposed,such as(1)pH dependent hydrogen binding energy as a major descriptor for HOR;and(2)bifunctional theory based on the contributions of both hydrogen and hydroxide adsorption for HOR in alkaline electrolyte.Here,we discuss the possible HOR mechanisms in alkaline electrolytes with the corresponding change in their Tafel behavior.Apart from the traditional Tafel-Volmer and Heyrovsky-Volmer HOR mechanisms,the recently proposed hydroxide adsorption step is also discussed to illustrate the difference in HOR mechanisms in acid and base.We further summarize the representative works of alkaline HOR catalyst design(e.g.,precious metals,alloy,intermetallic materials,Ni-based alloys,carbides,nitrides,etc.),and briefly describe their fundamental HOR reaction mechanism to emphasize the difference in elementary reaction steps in alkaline medium.The strategy of strengthening local interaction that facilitates both H2 desorption and Hads+OHads recombination is finally proposed for future HOR catalyst design in alkaline environment.
基金This work was sup-ported by the Australian Research Council Discovery Projects(Grant Nos.ARC DP200103332 and ARC DP200103315)。
文摘Electrochemical water splitting powered by renewables-generated electricity represents a promising approach for green hydrogen production.However,the sluggish kinetics for the hydrogen evolution reaction(HER)under an alkaline medium causes a massive amount of energy losses,hindering large-scale production.Exploring efficient and low-cost catalyst candidates for large-scale H_(2) generation becomes a crucial demand.Single-atom catalysts(SACs)demonstrate great promise for enabling efficient alkaline HER catalysis at maximum atom utilization efficiency.In this review,we provide a comprehensive overview of the recent progress in SACs for the HER application in alkaline environments.The fundamentals of alkaline HER are first introduced,followed by a justification of the need to develop SACs.The rational design of the SACs including the inherent element property,coordination environment,SAC morphology,and SAC mass loading are highlighted.To facilitate the development of SACs for alkaline HER,we further propose the remaining challenges and perspectives in this research field.
基金financially supported by the National Natural Science Foundation of China (Grants no. 21376283, 21436003 and 21576032)
文摘This work demonstrates the outstanding performance of alloyed Au1 Pt1 nanoparticles on hydrogen oxidation reaction(HOR)in alkaline solution.Due to the weakened hydrogen binding energy caused by uniform incorporation of Au,the alloyed Au1Pt1/C nanoparticles exhibit superior HOR activity than commercial PtRu/C.On the contrary,the catalytic performance of the phase-segregated Au2Pt1/C and Au1Pt1/C bimetallic nanoparticles in HOR is significantly worse.Moreover,Au1Pt1/C shows a remarkable durability with activity dropping only 4% after 3000 CV cycles,while performance attenuation of commercial PtRu/C is high up to 15% under the same condition.Our results indicate that the alloyed Au1Pt1/C is a promising candidate to substitute commercial PtRu/C for hydrogen oxidation reaction in alkaline electrolyte.
文摘A series of NiMoO_(4)-nano rod/carbon cloth composite electrodes with different loadings(x)of NiMoO_(4)-NRs was synthesized with a view to implementing an efficient hydrogen evolution reaction(HER).The NiMoO_(4) nano-rods(NRs)were prepared by growing them directly on carbon cloth(CC)via a simple hydrothermal reaction coupled with an annealing treatment.The resulting NiMoO_(4)-NR/CC-x composites served directly as electrodes for electrolysis of an alkaline medium and a simulated sea water.The results indicated that among the NiMoO_(4)-NR/CC-x composites,the NiMoO_(4)-NR/CC-10 composite possessed the highest HER activity with an overpotential of 244.8 mV at 10 mA/cm^(2),a Tafel slope of 95 mV/dec,the fastest charge transfer rate(R_(ct)<1Ω)and good stability in alkaline media.Even in simulated seawater,the NiMoO_(4)-NR/CC-10 composite showed good stability.The outstanding HER activity and stability may originate from the strong interaction between Ni and Mo in the NiMoO_(4) NRs as well as the efficient charge transfer process and the rate of the HER due to the synergistic effect involving the CC and NiMoO_(4) NRs.
基金supported by the National Natural Science Foundation of China(21573083)the 1000 Young Talent(to Deli Wang)initiatory financial support from Huazhong University of Science and Technology(HUST)~~
文摘The search for active,stable,and cost-effective electrocatalysts for hydrogen evolution reaction(HER)is desirable,but it remains a great challenge in the overall water splitting.Here,we report the synthesis of nickel boron nanoparticles supported on Vulcan carbon(Ni-B)via a simple,yet scalable,two-step chemical reduction–annealing strategy.The results of the electrochemical measurements suggest that the overpotentials of Ni-B-400 are 114 and 215 mV(in 1 mol L^–1 KOH)at current densities of 10 and 40 mA cm^?2,respectively,indicating an exceedingly good electrocatalytic activity in the HER.More importantly,Ni-B maintains a current density of 7.6 mA cm^-2 at an overpotential of 0.15 V for 20 h in the durability test.The excellent HER activity of Ni-B-400 is derived from the small particle size and the expanded lattice of Ni,which can optimize the hydrogen absorption energy and enhance the electrocatalytic properties.
基金Changwon National University in 2008 and National IT Industry Program Agency(NIPA-2009-C-C1090-0903-0007)
文摘Plasma electrolytic oxidation （PEO） is carried out on 6061 Al-alloys in a weak alkaline electrolyte containing NaOH, Na2SiO3 and NaCl. Centered on the correlation of composition and structure, analyses by means of X-ray diffration （XRD）, scanning electron microscope （SEM） and energy dispersive spectrometry （EDS） are conducted on the specimens, which have been PEO-treated under hybrid voltages of different direct current （DC） values （140-280 V） with constant alternate current （AC） amplitude （200 V）. Attention is paid to the composition, properties and growth mechanism of oxide layers formed with hybrid voltages. Moreover, the main effects of DC value are discussed. Ceramic layers with a double-layer structure which combines hard outer and soft inner layers are found to be consist of α-Al2O3,γ-Al2O3 and mullite. With the DC values increasing, the growth of the ceramic layers tends to have increasingly obvious three-stage feature.
基金supported by the National Natural Science Foundation of China(22279036)the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003).
文摘The anion exchange membrane fuel cell(AEMFC)enables the use of non-noble metal catalysts,greatly reducing the cost of fuel cells.Nickel-based materials are considered the most promising anode catalysts for practical applications in low-cost AEMFCs,but designing Ni-based catalysts with breakthrough performance remains a major challenge due to the slow kinetics of the anodic hydrogen oxidation reaction(HOR)in alkaline media.In this review,the electrocatalytic mechanisms of the alkaline HOR and the rigorous methods for assessing the performance of Ni-based catalysts are presented as the cornerstones for designing Ni-based catalysts.Alignment with the modulated geometric and electronic properties of Ni-based catalysts is thoroughly discussed,based on the principles of mechanism and performance evaluation.An element navigation map is presented to guide the precise design of efficient Ni-based non-noble metal catalysts for the alkaline HOR,and the current challenges and future prospects are outlined to provide valuable directions for new research about the alkaline HOR on Ni.This review not only offers insights into the rational design of Ni-based electrocatalysts but also provides a blueprint for the commercialization of cost-effective AEMFCs.
基金supported by the Joint Funds of the National Natural Science Foundation of China(No.U22A20140)University of Jinan Disciplinary Cross-Convergence Construction Project 2023(No.XKJC-202309)+4 种基金Jinan City-School Integration Development Strategy Project(No.JNSX2023015)National Natural Science Foundation of China(No.22409071)Natural Foundation of Shandong Province(No.ZR2024QB120)Youth Innovation Group Plan of Shandong Province(No.2024KJG046)Higher-Level Talent Initial Scientific Research and Discipline Construction Fund(511/1009530).
文摘Nickel/cobalt-based materials are promising cathodes owing to the high redox potential,high specific capacity,and long cycling performance.However,with the mass-loading of the electrode increasing,it greatly hinders the ion diffusion and charge transport,resulting in serious decrease of the electrode capacity.Herein,a hierarchical nickel-cobalt-based porous nanoflower structure(NiCo-Nanoflower)composed of numerous ultrathin nanosheets is synthesized,which significantly enhances the surface area and provides additional active sites.Besides,the abundant oxygen defects in NiCo-Nanoflower significantly enhance its electrical conductivity.Therefore,the NiCo-Nanoflower electrode exhibits a high reversible capacity of up to 210.4 mAh g^(−1)at 0.5 A g^(−1)and excellent rate retention of 180.4 mAh g^(−1)at 8 A g^(−1)(104 mA cm^(−2))even under high areal mass loading of 13 mg cm^(−2).Upon assembly in a NiCo//Zn battery system,the configuration demonstrates exceptional electrochemical stability,maintaining 74.3%capacity retention after 5000 cycles.This work demonstrates that NiCo-Nanoflower,equipped with three-dimensional microstructure and oxygen-enriched defects,holds significant potential for application in high-mass-loading cathodes for alkaline aqueous zinc batteries.
基金financially supported by the National Natural Science Foundation of China(21573167,21633008,91545205,21125312)National Key Research and Development Program(2016YFB0101203)+2 种基金the National Basic Research Program(2012CB932800,2012CB215500)the Doctoral Fund of Ministry of Education of China(20110141130002)the Fundamental Research Funds for the Central Universities(2014203020207)
文摘An environmentally friendly precursor, adenosine, has been used as a dual source of C and N to synthesize nitrogen-doped carbon catalyst with/without Fe. A hydrothermal carbonization method has been used and water is the carbonization media. The morphology of samples with/without Fe component has been compared by HRTEM, and the result shows that Fe can promote the graphitization of carbon. Further electro-chemical test shows that the oxygen reduction reaction（ORR） catalytic activity of Fe-containing sample（C–Fe N） is much higher than that of the Fe-free sample（C–N）. Additionally, the intermediates of C–Fe N formed during each synthetic procedure have been thoroughly characterized by multiple methods,and the function of each procedure has been discussed. The C–Fe N sample exhibits high electro-catalytic stability and superior electro-catalytic activity toward ORR in alkaline media, with its half-wave potential 20 mV lower than that of commercial Pt/C（40 wt%）. It is further incorporated into alkaline polymer electrolyte fuel cell（APEFC） as the cathode material and led to a power density of 100 m W/cm;.
基金supported in part by the National Natural Science Foundation of China(Nos.51925102 and 52273277)H.-X.Z.acknowledges funding from the National Natural Science Foundation of China Outstanding Youth Science Foundation of China(Overseas).
文摘Electrocatalytic reduction of nitrate(NO_(3)^(−))and nitride(NO_(2)^(−))to ammonia(NH3)is of wide interest as a promising alternative to the energy-intensive Haber-Bosch route for mitigating the vast energy consumption and the accompanied carbon dioxide emission,as well as benefiting for the relevant sewage treatment.However,exploring an efficient and low-cost catalyst with high atomic utilization that can effectively facilitate the slow multi-electron transfer process remains a grand challenge.Herein,we present an efficient hydrogenation of NO_(3)^(−)/NO_(2)^(−)species to NH3 in both alkaline and neutral environments over the Fe_(2)(MoO_(4))_(3)derived hybrid electrocatalyst with the metallic Fe site on FeMoO_(4)(Fe/FeMoO_(4)).The Mo ingredient can play a synergistically positive role in further promoting the NH_(3) production on Fe.As a result,Fe/FeMoO_(4)behaves well in the electrochemical NH_(3) generation from NO_(2)^(−)with a maximum NH_(3) Faradaic efficiency(FE)of 96.53%and 87.68%in alkaline and neutral electrolyte,corresponding to the NH_(3) yield rate of 640.68 and 302.56 mg·h^(−1)·mg_(cat.)^(−1),respectively,which outperforms the Fe and Mo counterpart and other similar catalyst,showing the robust catalytic capacity of each active site.
