A hydrogen evolution-assisted one-pot aqueous approach was developed for facile synthesis of trimetallic Pd Ni Ru alloy nanochain-like networks（Pd Ni Ru NCNs） by only using KBHas the reductant, without any specific ...A hydrogen evolution-assisted one-pot aqueous approach was developed for facile synthesis of trimetallic Pd Ni Ru alloy nanochain-like networks（Pd Ni Ru NCNs） by only using KBHas the reductant, without any specific additive（e.g. surfactant, polymer, template or seed）. The products were mainly investigated by transmission electron microscopy（TEM）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）. The hierarchical architectures were formed by the oriented assembly growth and the diffusioncontrolled deposition in the presence of many in-situ generated hydrogen bubbles. The architectures had the largest electrochemically active surface area（ECSA） of 84.32 mgPdthan Pd Ni nanoparticles(NPs,65.23 mgPd), Pd Ru NPs(23.12 mgPd), Ni Ru NPs（nearly zero）, and commercial Pd black(6.01 mgPd), outperforming the referenced catalysts regarding the catalytic characters for hydrazine oxygen reaction（HOR）. The synthetic route provides new insight into the preparation of other trimetallic nanocatalysts in fuel cells.展开更多
The performance of hematite(α-Fe_(2)O_(3))photoanodes for photoelectrochemical(PEC)water splitting has been limited to around 2-5 mA cm^(-2)under standard conditions due to their short hole diffusion length and slugg...The performance of hematite(α-Fe_(2)O_(3))photoanodes for photoelectrochemical(PEC)water splitting has been limited to around 2-5 mA cm^(-2)under standard conditions due to their short hole diffusion length and sluggish oxygen evolution reaction kinetics.This work overcomes those challenges through a synergistic strategy that co-designs the hematite architecture and the surface reaction pathway.We introduce a textured and hierarchically porous Ti-doped Fe_(2)O_(3)(tp-Fe_(2)O_(3))photoanode,synthesized via multi-cycle growth and flame annealing method.This unique architecture features a high texture(110),enlarged surface area,and hierarchically porous structure,which enable significantly enhanced bulk charge transport and interfacial charge transfer compared to typical nanorod Ti-doped Fe_(2)O_(3)(nr-Fe_(2)O_(3)).As a result,the tp-Fe_(2)O_(3)photoanode achieves a photocurrent density of 3.1 mA cm^(-2)at 1.23 V vs.RHE with exceptional stability over 105 h,notably without any co-catalyst.By replacing the OER with the hydrazine oxidation reaction,the photocurrent further reaches a record-high level of 7.1 mA cm^(-2)at 1.23 V_(RHE).Finally,when we integrate the tp-Fe_(2)O_(3)with a commercial Si solar cell,it achieves a solar-to-hydrogen efficiency of 8.7%-the highest reported value for any Fe_(2)O_(3)-based PVtandem system.This work provides critical insights into rational Fe_(2)O_(3)photoanode design and highlights the potential of hydrazine as an efficient alternative anodic reaction,enabling waste valorization.展开更多
The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly effici...The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly efficient catalysts for the HzOR.Herein,we report amorphous ruthenium nanosheets(a-Ru NSs)with a thickness of approximately 9.6 nm.As a superior bifunctional electrocatalyst,a-Ru NSs exhibited enhanced electrocatalytic performance toward both the HzOR and hydrogen evolution reaction(HER),outperforming benchmark Pt/C catalysts,where the a-Ru NSs achieved a work-ing potential of merely-76 mV and a low overpotential of only 17 mV to attain a current density of 10 mA·cm^(-2) for the HzOR and HER,respectively.Furthermore,a-Ru NSs displayed a low cell voltage of 28 mV at 10 mA·cm^(-2) for overall hy-drazine splitting in a two-electrode electrolyzer.In situ Raman spectra revealed that the a-Ru NSs can efficiently promote N‒N bond cleavage,thereby producing more*NH_(2)and accelerating the progress of the reaction.展开更多
Zn-CO_(2)batteries(ZCBs)are promising for CO_(2)conversion and electric energy release.However,the ZCBs couple the electrochemical CO_(2)reduction(ECO_(2)R)with the oxygen evolution reaction and competitive hydrogen e...Zn-CO_(2)batteries(ZCBs)are promising for CO_(2)conversion and electric energy release.However,the ZCBs couple the electrochemical CO_(2)reduction(ECO_(2)R)with the oxygen evolution reaction and competitive hydrogen evolution reaction,which normally causes ultrahigh charge voltage and CO_(2)conversion efficiency attenuation,thereby resulting in~90%total power consumption.Herein,isolated FeN_(3)sites encapsulated in hierarchical porous carbon nanoboxes(Fe-HPCN,derived from the thermal activation process of ferrocene and polydopamine-coated cubic ZIF-8)were proposed for hydrazine-assisted rechargeable ZCBs based on ECO_(2)R(discharging process:CO_(2)+2H+→CO+H_(2)O)and hydrazine oxidation reaction(HzOR,charging process:N_(2)H_(4)+4OH−→N_(2)+4H_(2)O+4e^(−)).The isolated FeN_(3)endows the HzOR with a lower overpotential and boosts the ECO_(2)R with a 96%CO Faraday efficiency(FECO).Benefitting from the bifunctional ECO_(2)R and HzOR catalytic activities,the homemade hydrazine-assisted rechargeable ZCBs assembled with the Fe-HPCN air cathode exhibited an ultralow charge voltage(decreasing by~1.84 V),excellent CO selectivity(FECO close to 100%),and high 89%energy efficiency.In situ infrared spectroscopy confirmed that Fe-HPCN can generate rate-determining*N_(2)and*CO intermediates during HzOR and ECO_(2)R.This paper proposes FeN_(3)centers for bifunctional ECO_(2)R/HzOR performance and further presents the pioneering achievements of ECO_(2)R and HzOR for hydrazine-assisted rechargeable ZCBs.展开更多
Molybdenum phosphides(MoP)are emerging as an attractive catalyst for water splitting due to their excellent activity and stability.However,most of the MoP synthesized so far are crystalline MoP with relatively fewer e...Molybdenum phosphides(MoP)are emerging as an attractive catalyst for water splitting due to their excellent activity and stability.However,most of the MoP synthesized so far are crystalline MoP with relatively fewer exposed active sites and low electrical conductivity.Here,we use a metallo-organic Mo precursor(MoO_(2)(acac)_(2))to create defect-rich crystalline MoP nanoparticles and uniformly anchor them on reduced graphene oxide(denoted as D-MoP/rGO).High-temperature thermal decomposition of the precursor generates gases,which induce a variety of defects in D-MoP/rGO along with a P-rich surface composition.The electrochemically active surface area of D-MoP/rGO is 8 times that of bulk MoP.D-MoP/rGO requires a small overpotential of 122 mV for the hydrogen evolution reaction(HER)to reach a current density of 10 mA cm^(-2).Furthermore,density functional theory(DFT)calculation results reveal that surface P sites are the key active sites,which favor the adsorption of H atoms and also act as an H deliverer to promote the HER.Importantly,D-MoP/rGO is also a highly active catalyst for the hydrazine oxidation reaction(HzOR)and requires a low overpotential of 84 mV to reach a current density of 10 mA cm^(-2).Thus,efficient HER||HzOR hybrid water-splitting can be realized using D-MoP/rGO,which can deliver a current density of 100 mA cm^(-2)at a small cell voltage of 0.74 V and undergo a stable 12 h operation.In summary,a simple method has been demonstrated to generate high-performance metal phosphide electrocatalysts for total water splitting.Furthermore,the material design concept of creating defective crystalline nanoparticles using gas generating metal precursors can serve as a general approach to create various catalytic active defective crystalline materials.展开更多
Utilizing the hydrazine-assisted water electrolysis for energy-efficient hydrogen production shows a promising application, which relies on the development and design of efficient bifunctional electrocatalysts. Herein...Utilizing the hydrazine-assisted water electrolysis for energy-efficient hydrogen production shows a promising application, which relies on the development and design of efficient bifunctional electrocatalysts. Herein, we reported a low-content Pt-doped Rh metallene(Pt-Rhene) for hydrazine-assisted water electrolysis towards energy-saving hydrogen(H_(2)) production, where the ultrathin metallene is constructed to provide enough favorable active sites for catalysis and improve atom utilization.Additionally, the synergistic effect between Rh and Pt can optimize the electronic structure of Rh for improving the intrinsic activity. Therefore, the required overpotential of Pt-Rhene is only 37 mV to reach a current density of-10 mA cm^(-2) in the hydrogen evolution reaction(HER), and the Pt-Rhene exhibits a required overpotential of only 11 mV to reach a current density of 10 mA cm^(-2) in the hydrazine oxidation reaction(HzOR). With the constructed HER-HzOR two-electrode system, the Pt-Rhene electrodes exhibit an extremely low voltage(0.06/0.19/0.28 V) to achieve current densities of 10/50/100 mA cm^(-2) for energy-saving H_(2) production, which greatly reduces the electrolysis energy consumption. Moreover,DFT calculations further demonstrate that the introduction of Pt modulates the electronic structure of Rh and optimizes the d-band center, thus enhancing the adsorption and desorption of reactant/intermediates in the electrocatalytic reaction.展开更多
The hydrazine oxidation-assisted hydrogen generation system significantly expands the applicability of hydrogen production technology.However,the complex intermediate transformations involved in the hydrazine oxidatio...The hydrazine oxidation-assisted hydrogen generation system significantly expands the applicability of hydrogen production technology.However,the complex intermediate transformations involved in the hydrazine oxidation reaction(HzOR)and hydrogen evolution reaction(HER)desperately need the development of dual-functional catalysts.Manipulating the d-band center of metal catalysts has been identified as one of the most effective approaches to enhance catalytic activity.Herein,Ir nanoparticles(NPs)anchored in B,N-codoped porous carbon(Ir@BNC)were developed and demonstrate excellent performances for both HER and HzOR in an alkaline medium,achieving 10 mA cm^(-2) at-25 and 18 mV,respectively.The overall hydrazine splitting(OHzS)electrolyzer reaches 200 mA cm^(-2) with a cell voltage of just 0.68 V.The direct liquid N2H4/H2O_(2) fuel cell(DHHPFC)assembly with Ir@BNC can achieve a maximum power density of 199.2 mW cm^(-2) at room temperature.Furthermore,an H2 production system using an OHzS device powered by DHHPFC realizes hydrogen production at a stable rate(53.08 mol h^(-1) m^(-2)).In-situ Raman tests and theoretical calculations unravel the metal-support interaction between Ir NPs and B,N-codoped porous carbon,optimizing the electronic structure and regulating the d-band center of Ir,reducing the adsorption energy of H*intermediates and N2H4 molecules,thus promoting the reaction processes of HER and HzOR.展开更多
Metallene has been widely considered as an advanced electrocatalytic material due to its large specific surface area and highly active reaction sites.Herein,we design and synthesize ultrathin rhodium metallene(Rh ML)w...Metallene has been widely considered as an advanced electrocatalytic material due to its large specific surface area and highly active reaction sites.Herein,we design and synthesize ultrathin rhodium metallene(Rh ML)with abundant wrinkles to supply surface-strained Rh sites for driving acetonitrile electroreduction to ethylamine(AER).The electrochemical tests indicate that Rh ML shows an ethylamine yield rate of 137.1 mmol gcat^(-1) h^(-1) in an acidic solution,with stability lasting up to 200 h.Theoretical calculations reveal that Rh ML with wrinkle-induced compressive strain not only shows a lower energy barrier in the rate-determining step but also facilitates the ethylamine desorption process compared to wrinkle-free Rh ML and commercial Rh black.The assembled electrolyzer with bifunctional Rh ML shows an electrolysis voltage of 0.41 V at 10 mA cm^(-2),enabling simultaneous ethylamine production and hydrazine waste treatment.Furthermore,the voltage of an assembled hybrid zinc-acetonitrile battery can effectively drive this electrolyzer to achieve the dual AER process.This study provides guidance for improving the catalytic efficiency of surface atoms in two-dimensional materials,as well as the electrochemical synthesis technology for series-connected battery-electrolyzer systems.展开更多
Hydrogen peroxide(H_(2)O_(2))production via electrochemical two-electron oxygen reduction reaction(ORR)holds a great promise for sustainable energy storage.However,the issues such as high energy consumption and diffic...Hydrogen peroxide(H_(2)O_(2))production via electrochemical two-electron oxygen reduction reaction(ORR)holds a great promise for sustainable energy storage.However,the issues such as high energy consumption and difficult extraction of thermodynamically unstable H_(2)O_(2) still need to be resolved.Herein,we reported a unified system for energy-out production and downstream conversion of H_(2)O_(2).By replacing the sluggish oxygen evolution reaction with a hydrazine oxidation reaction(HzOR),the cell of twoelectron ORR coupled with HzOR achieves the co-generation of electricity energy and valuable H_(2)O_(2).By employing Ru single atoms anchored on cobalt hydroxide(for HzOR)and NiSe_(2)(for ORR)as electrocatalysts,both exhibiting onset potentials near the theoretical values for their respective reactions,the ORR‖HzOR cell exhibits an energy output of 3.58 mW cm^(-2) and generates 0.66 kWh of electricity per kg of H_(2)O_(2).with a production rate of 583 mmol h^(-1) H_(2)O_(2).The produced H_(2)O_(2) was subsequently in-situ upgraded via three downstream conversion pathways to yield value-added products of sodium percarbonate,sodium peroxyborate,and ethylene glycol.A techno-economic analysis confirmed the economic viability of this ORR‖HzOR coupled with downstream conversion system.展开更多
Seawater electrolysis could address the water scarcity issue and realize the grid-scale production of carbon-neutral hydrogen,while facing the challenge of high energy consumption and chloride corrosion.Thermodynamica...Seawater electrolysis could address the water scarcity issue and realize the grid-scale production of carbon-neutral hydrogen,while facing the challenge of high energy consumption and chloride corrosion.Thermodynamically more favorable hydrazine oxidation reaction(HzOR)assisted water electrolysis is efficiency for energy-saving and chlorine-free hydrogen production.Herein,the MoNi alloys supported on MoO_(2) nanorods with enlarged hollow diameter on Ni foam(MoNi@NF)are synthesized,which is constructed by limiting the outward diffusion of Ni via annealing and thermal reduction of NiMoO_(4) nanorods.When coupling HzOR and hydrogen evolution reaction(HER)by employing MoNi@NF as both anode and cathode in two-electrode seawater system,a low cell voltage of 0.54 V is required to achieve 1,000 mA·cm^(−2) and with long-term durability for 100 h to keep above 100 mA·cm^(−2) and nearly 100%Faradaic efficiency.It can save 2.94 W·h to generate per liter H_(2) relative to alkaline seawater electrolysis with 37%lower energy equivalent input.展开更多
Copper nanoparticles-decorated polyaniline- derived mesoporous carbon that can serve as noble metal-free electrocatalyst for the hydrazine oxidation reaction （HzOR） is synthesized via a facile synthetic route. The m...Copper nanoparticles-decorated polyaniline- derived mesoporous carbon that can serve as noble metal-free electrocatalyst for the hydrazine oxidation reaction （HzOR） is synthesized via a facile synthetic route. The material exhibits excellent electrocatalytic activity toward HzOR with low overpotential and high current density. The material also remains stable during the electrocatalytic reaction for long time. Its good electro- catalytic performance makes this material a promising alternative to conventional noble metal-based catalysts （e.g., Pt） that are commonly used in HzOR-based fuel cells.展开更多
Developing high performance anode catalysts for oxygen evolution reaction (OER) and hydrazine oxidation reaction (HzOR) at large current density is an efficient pathway to produce hydrogen. Herein, we synthesize a FeW...Developing high performance anode catalysts for oxygen evolution reaction (OER) and hydrazine oxidation reaction (HzOR) at large current density is an efficient pathway to produce hydrogen. Herein, we synthesize a FeWO_(4)-WO_(3) heterostructure catalyst growing on nickel foam (FeWO_(4)-WO_(3)/NF) by a combination of hydrothermal and calcination method. It shows good catalytic activity with ultralow potentials for OER (ζ_(10) = 1.43 V, ζ_(1.000) = 1.56 V) and HzOR (ζ_(10) = −0.034 V, ζ_(1.000) = 0.164 V). Moreover, there is little performance degradation after being tested for _(10)0 h at 1,000 (OER) and _(10)0 (HzOR) mA·cm−2, indicating good stability. The superior performance could be attributed to the wolframite structure and heterostructure: The former provides a high electrical conductivity to ensure the electronic transfer capability, and the later induces interfacial electron redistribution to enhance the intrinsic activity and stability. The work offers a brand-new way to prepare good performance catalysts for OER and HzOR, especially at large current density.展开更多
Rh has been widely studied as a catalyst for the promising hydrazine oxidation reaction that can replace oxygen evolution reactions for boosting hydrogen production from hydrazine-containing wastewater.Despite Rh bein...Rh has been widely studied as a catalyst for the promising hydrazine oxidation reaction that can replace oxygen evolution reactions for boosting hydrogen production from hydrazine-containing wastewater.Despite Rh being expensive,only a few studies have examined its electrocatalytic mass activity.Herein,surface-limited cation exchange and electrochemical activation processes are designed to remarkably enhance the mass activity of Rh.Rh atoms were readily replaced at the Ni sites on the surface of NiOOH electrodes by cation exchange,and the resulting RhOOH compounds were activated by the electrochemical reduction process.The cation exchange-derived Rh catalysts exhibited particle sizes not exceeding 2 nm without agglomeration,indicating a decrease in the number of inactive inner Rh atoms.Consequently,an improved mass activity of 30 A mg_(Rh)^(-1)was achieved at 0.4 V versus reversible hydrogen electrode.Furthermore,the two-electrode system employing the same CE-derived Rh electrodes achieved overall hydrazine splitting over 36 h at a stable low voltage.The proposed surface-limited CE process is an effective method for reducing inactive atoms of expensive noble metal catalysts.展开更多
Electrolyzing seawater is a promising solution to produce hydrogen,which is hindered by low-efficiency oxygen evolution reaction(OER)and noxious chloride chemistry.Herein,the Fe-Co_(2)P/CeO_(2)heterostructure nanoshee...Electrolyzing seawater is a promising solution to produce hydrogen,which is hindered by low-efficiency oxygen evolution reaction(OER)and noxious chloride chemistry.Herein,the Fe-Co_(2)P/CeO_(2)heterostructure nanosheet arrays are developed to achieve energy-saving and chlorine-free hydrogen generation by coupling hydrogen evolution reaction(HER)with hydrazine oxidation reaction(HzOR)in seawater.The Fe-Co_(2)P/CeO_(2)realizes current densities of 10 and 400 mA·cm^(-2)at 52 and204 mV for HER.The anode potential is significantly decreased after replacing OER with HzOR.Theoretical calculations display that the electronic structure of Fe-Co_(2)P can be regulated after coupling CeO_(2),which lowers the water dissociation barrier and optimizes hydrogen adsorption-free energy,thus boosting catalytic kinetics.Significantly,the hybrid seawater electrolyzer produces hydrogen at ultralow cell voltages,greatly reducing traditional water electrolysis voltages and avoiding hazardous chlorine chemistry.This study provides an avenue to exploit advanced catalysts for acquiring hydrogen with energy-efficiency and chlorine-free from abundant ocean.展开更多
Direct hydrazine‐hydrogen peroxide fuel cells(DHzHPFCs)offer unique advantages for air‐independent applications,but their commercialization is impeded by the lack of high‐performance and low‐cost catalysts.This st...Direct hydrazine‐hydrogen peroxide fuel cells(DHzHPFCs)offer unique advantages for air‐independent applications,but their commercialization is impeded by the lack of high‐performance and low‐cost catalysts.This study reports a novel dual‐site Co‐Zn catalyst designed to enhance the hydrazine oxidation reaction(HzOR)activity.Density functional theory calculations suggested that incorporating Zn into Co catalysts can weaken the binding strength of the crucial N_(2)H_(3)*intermediate,which limits the ratedetermining N_(2)H_(3)*desorption step.The synthesized p‐Co_(9)Zn1 catalyst exhibited a remarkably low reaction potential of−0.15 V versus RHE at 10mAcm−2,outperforming monometallic Co catalysts.Experimental and computational analyses revealed dual active sites at the Co/ZnO interface,which facilitate N_(2)H_(3)*desorption and subsequent N_(2)H_(2)*formation.A liquidN_(2)H_(4)‐H_(2)O_(2)fuel cell with p‐Co_(9)Zn1 catalyst achieved a high open circuit voltage of 1.916 V and a maximum power density of 195mWcm^(−2),demonstrating the potential application of the dual‐site Co‐Zn catalyst.This rational design strategy of tuning the N_(2)H_(3)*binding energy through bimetallic interactions provides a pathway for developing efficient and economical non‐precious metal electrocatalysts for DHzHPFCs.展开更多
Layered double hydroxides have demonstrated great potential for the oxygen evolution reaction,which is a crucial half-reaction of overall water splitting.However,it remains challenging to apply layered double hydroxid...Layered double hydroxides have demonstrated great potential for the oxygen evolution reaction,which is a crucial half-reaction of overall water splitting.However,it remains challenging to apply layered double hydroxides in other electrochemical reactions with high efficiency and stability.Herein,we report two-dimensional multifunctional layered double hydroxides derived from metalorganic framework sheet precursors supported by nanoporous gold with high porosity,which exhibit appealing performances toward oxygen/hydrogen evolution reactions,hydrazine oxidation reaction,and overall hydrazine splitting.The as-prepared catalyst only requires an overpotential of 233 mV to reach 10 mA·cm^(-2) toward oxygen evolution reaction.The overall hydrazine splitting cell only needs a cell voltage of 0.984 V to deliver 10 mA·cm^(-2),which is far more superior than that of the overall water splitting system(1.849 V).The appealing performances of the catalyst can be contributed to the synergistic effect between the metal components of the layered double hydroxides and the supporting effect of the nanoporous gold substrate,which could endow the sample with high surface area and excellent conductivity,resulting in superior activity and stability.展开更多
The hydrazine oxidation reaction(HzOR)boasts a low theoretical working potential,rendering it promising for applications in energy-saving hydrogen production and treatment of hydrazine-containing wastewater.Herein,Ni ...The hydrazine oxidation reaction(HzOR)boasts a low theoretical working potential,rendering it promising for applications in energy-saving hydrogen production and treatment of hydrazine-containing wastewater.Herein,Ni species-incorporated CoP nanosheet arrays encapsulated in N-doped carbon layers grown on Ni foam(Ni-CoP@NC)have been synthesized.Due to the outstanding synergistic effect resulting from metal incorporation and N-doped carbon encapsulation,a high current density of 1 A cm^(-2)at low potentials of-143 mV and 51 mV for the hydrogen evolution reaction(HER)and HzOR is achieved by using Ni-CoP@NC,respectively.Furthermore,the Ni-CoP@NC-assembled hydrazine-assisted seawater electrolysis system exhibits a remarkable decrease in voltage input compared to conventional and other hybrid electrolysis devices,achieving an ultra-low voltage of just 0.49 V to attain a current density of 1 A cm^(-2).Remarkably,a five-fold cost reduction is offered by this system compared to conventional water electrolysis.Moreover,a novel multi-powered hydrogen production system is proposed,which consists of renewable energy sources,direct hydrazine fuel cells,rechargeable Zn-hydrazine batteries,and hydrazine-assisted seawater electrolysis.This system showcases the unique advantages of the HzOR and its potential contribution to electrochemical energy conversion technologies for sustainable energy supply.展开更多
Coupling the thermodynamically favorable hydrazine oxidation reaction(HzOR)with the hydrogen evolution reaction(HER)in a hybrid water electrolyzer is an effective strategy to improve the energy efficiency of large-sca...Coupling the thermodynamically favorable hydrazine oxidation reaction(HzOR)with the hydrogen evolution reaction(HER)in a hybrid water electrolyzer is an effective strategy to improve the energy efficiency of large-scale high-purity H2 production,while achieving pollutant degradation.Recently,various advanced materials have been exploited as electrocatalysts for hydrazine-assisted water electrolysis,but a fundamental understanding of them and a comprehensive summary are lacking to date.In this review,we provide a comprehensive review of advanced electrocatalysts available for HzOR-assisted water electrolysis,as well as various regulatory strategies based on precious metals and non-noble metal-based materials,such as doping,heterostructures,single-atoms,and alloying.Moreover,the structure-activity relationship including electronic structure,surface properties,and catalytic performance of the electrocatalysts is systematically discussed.Given the importance and unique advantages of direct hydrazine hydrate-assisted seawater electrolysis and self-powered electrolyzers,we also present systematic summaries of material design,performance evaluation,and mechanism studies.Finally,several key challenges and future perspectives about hydrazine-assisted water electrolysis are discussed to offer insight into large-scale H2 production for energy-saving pathways.展开更多
Electrochemical overall water splitting for sustainable hydrogen generation is severely hindered by anode water electrooxidation with sluggish kinetics.Thus,using the thermodynamically favorable hydrazine oxidation re...Electrochemical overall water splitting for sustainable hydrogen generation is severely hindered by anode water electrooxidation with sluggish kinetics.Thus,using the thermodynamically favorable hydrazine oxidation reaction(HzOR)to substitute the oxygen evolution reaction(OER)has attracted ever-growing attention.Herein,well-defined copper selenide nanoflakes,in situ grown on copper foam(termed Cu_(x)Se/CF),were synthesized by a one-step selenization strategy,which are composed of nonstoichiometric Cu_(2-x)Se with stable Cu2Se berzelianite that show remarkable bifunctional activities for the hydrogen evolution reaction(HER)and HzOR electrocatalysis.Investigations into the mechanisms uncovered that the high copper deficiencies in the Cu_(2-x)Se phase make it both an excellent electron donor and acceptor,leading to faster electron transfers across the catalyst(electrode)-electrolyte interface,which greatly boosts the reaction kinetics of HER and HzOR processes.Meanwhile,the Cu2Se berzelianite phase plays a pivotal role in the long-term electrocatalytic operation for the HER and HzOR.Encouraged by this synergistic advantage,the CuxSe/CF catalysts were further employed as good bifunctional catalysts for electrocatalytic hydrazine-assisted overall water splitting with a low cell voltage of 0.49 V at 25 mA cm^(-2),as well as having good stability over 20 h,which indicates the broad potential for future industrialization of a sustainable hydrogen-based society.展开更多
Electrochemical H_(2) production from water splitting is an environmentally sustainable technique but remains a great challenge due to the sluggish anodic oxygen evolution reaction(OER).Replacing the OER with the ther...Electrochemical H_(2) production from water splitting is an environmentally sustainable technique but remains a great challenge due to the sluggish anodic oxygen evolution reaction(OER).Replacing the OER with the thermodynamically more favorable electrocatalytic oxidation process is an effective strategy for highly efficient H_(2) generation.Herein,Mn-doped CoS_(2) has predicted an excellent bifunctional electrocatalyst for the hydrogen evolution reaction(HER)and the hydrazine oxidation reaction(HzOR).With the introduction of Mn,the Gibbs free energy of the adsorbed H* and the potential rate-limiting step(the dehydrogenation of *NH_(2)NH_(2) to *NHNH_(2))for the HzOR process of the catalyst can be significantly reduced.As expected,the Mn-CoS_(2) catalyst exhibited excellent catalytic activity and robust long-term stability for the HER and HzOR.In detail,the Mn-CoS_(2) catalyst only acquired potentials of 46 and 77 mV versus the reversible hydrogen electrode for achieving a current density of 10 mA cm^(-2) for the cathodic HER and anodic HzOR,respectively.In addition,the Mn-CoS_(2) electrode only needs a cell voltage of 447 mV to output 200 mA cm^(-2) in the overall hydrazine splitting system as well as exhibits a robust longterm H_(2) production.This work provides theoretical guidance for the design of advanced bifunctional electrocatalysts and promotes high efficiency and energy-saving H_(2) production technology.展开更多
基金financially supported by the Nation Natural Science Foundation of China(No.21475118)
文摘A hydrogen evolution-assisted one-pot aqueous approach was developed for facile synthesis of trimetallic Pd Ni Ru alloy nanochain-like networks（Pd Ni Ru NCNs） by only using KBHas the reductant, without any specific additive（e.g. surfactant, polymer, template or seed）. The products were mainly investigated by transmission electron microscopy（TEM）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）. The hierarchical architectures were formed by the oriented assembly growth and the diffusioncontrolled deposition in the presence of many in-situ generated hydrogen bubbles. The architectures had the largest electrochemically active surface area（ECSA） of 84.32 mgPdthan Pd Ni nanoparticles(NPs,65.23 mgPd), Pd Ru NPs(23.12 mgPd), Ni Ru NPs（nearly zero）, and commercial Pd black(6.01 mgPd), outperforming the referenced catalysts regarding the catalytic characters for hydrazine oxygen reaction（HOR）. The synthetic route provides new insight into the preparation of other trimetallic nanocatalysts in fuel cells.
基金supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.RS-2024-00335976)。
文摘The performance of hematite(α-Fe_(2)O_(3))photoanodes for photoelectrochemical(PEC)water splitting has been limited to around 2-5 mA cm^(-2)under standard conditions due to their short hole diffusion length and sluggish oxygen evolution reaction kinetics.This work overcomes those challenges through a synergistic strategy that co-designs the hematite architecture and the surface reaction pathway.We introduce a textured and hierarchically porous Ti-doped Fe_(2)O_(3)(tp-Fe_(2)O_(3))photoanode,synthesized via multi-cycle growth and flame annealing method.This unique architecture features a high texture(110),enlarged surface area,and hierarchically porous structure,which enable significantly enhanced bulk charge transport and interfacial charge transfer compared to typical nanorod Ti-doped Fe_(2)O_(3)(nr-Fe_(2)O_(3)).As a result,the tp-Fe_(2)O_(3)photoanode achieves a photocurrent density of 3.1 mA cm^(-2)at 1.23 V vs.RHE with exceptional stability over 105 h,notably without any co-catalyst.By replacing the OER with the hydrazine oxidation reaction,the photocurrent further reaches a record-high level of 7.1 mA cm^(-2)at 1.23 V_(RHE).Finally,when we integrate the tp-Fe_(2)O_(3)with a commercial Si solar cell,it achieves a solar-to-hydrogen efficiency of 8.7%-the highest reported value for any Fe_(2)O_(3)-based PVtandem system.This work provides critical insights into rational Fe_(2)O_(3)photoanode design and highlights the potential of hydrazine as an efficient alternative anodic reaction,enabling waste valorization.
基金supported by the National Key R&D Program of China(2018YFA0702001)National Natural Science Foundation of China(22371268,22301287)+3 种基金Fundamental Research Funds for the Central Universities(WK2060000016)Anhui Provincial Natural Science Foundation(2208085J09,2208085QB33)Collaborative Innovation Program of Hefei Science Center,CAS(2022HSC-CIP020)Youth Innovation Promotion Association of the Chinese Academy of Science(2018494)and USTC Tang Scholar.
文摘The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly efficient catalysts for the HzOR.Herein,we report amorphous ruthenium nanosheets(a-Ru NSs)with a thickness of approximately 9.6 nm.As a superior bifunctional electrocatalyst,a-Ru NSs exhibited enhanced electrocatalytic performance toward both the HzOR and hydrogen evolution reaction(HER),outperforming benchmark Pt/C catalysts,where the a-Ru NSs achieved a work-ing potential of merely-76 mV and a low overpotential of only 17 mV to attain a current density of 10 mA·cm^(-2) for the HzOR and HER,respectively.Furthermore,a-Ru NSs displayed a low cell voltage of 28 mV at 10 mA·cm^(-2) for overall hy-drazine splitting in a two-electrode electrolyzer.In situ Raman spectra revealed that the a-Ru NSs can efficiently promote N‒N bond cleavage,thereby producing more*NH_(2)and accelerating the progress of the reaction.
基金National Natural Science Foundation of China,Grant/Award Number:12274118Double First Class University Plan,Grant/Award Number:C176220100042+2 种基金National Natural Science Foundation of China-Yunnan Joint Fund,Grant/Award Number:U2002213Open Foundation of Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured Materials,Grant/Award Number:2022GXYSOF10Henan Center for Outstanding Overseas Scientists,Grant/Award Number:GZS2023007.
文摘Zn-CO_(2)batteries(ZCBs)are promising for CO_(2)conversion and electric energy release.However,the ZCBs couple the electrochemical CO_(2)reduction(ECO_(2)R)with the oxygen evolution reaction and competitive hydrogen evolution reaction,which normally causes ultrahigh charge voltage and CO_(2)conversion efficiency attenuation,thereby resulting in~90%total power consumption.Herein,isolated FeN_(3)sites encapsulated in hierarchical porous carbon nanoboxes(Fe-HPCN,derived from the thermal activation process of ferrocene and polydopamine-coated cubic ZIF-8)were proposed for hydrazine-assisted rechargeable ZCBs based on ECO_(2)R(discharging process:CO_(2)+2H+→CO+H_(2)O)and hydrazine oxidation reaction(HzOR,charging process:N_(2)H_(4)+4OH−→N_(2)+4H_(2)O+4e^(−)).The isolated FeN_(3)endows the HzOR with a lower overpotential and boosts the ECO_(2)R with a 96%CO Faraday efficiency(FECO).Benefitting from the bifunctional ECO_(2)R and HzOR catalytic activities,the homemade hydrazine-assisted rechargeable ZCBs assembled with the Fe-HPCN air cathode exhibited an ultralow charge voltage(decreasing by~1.84 V),excellent CO selectivity(FECO close to 100%),and high 89%energy efficiency.In situ infrared spectroscopy confirmed that Fe-HPCN can generate rate-determining*N_(2)and*CO intermediates during HzOR and ECO_(2)R.This paper proposes FeN_(3)centers for bifunctional ECO_(2)R/HzOR performance and further presents the pioneering achievements of ECO_(2)R and HzOR for hydrazine-assisted rechargeable ZCBs.
基金funded by the National Natural Science Foundation of China(51702213)support from the Shanghai Chenguang Program(17CG48),the Shanghai Pujiang Program(17PJ1406900)+2 种基金the Shanghai Science and Technology Commission(18060502300)supports from the Australian Research Council under the Future Fellowships scheme(FT160100107)Discovery Programme(DP180102210).
文摘Molybdenum phosphides(MoP)are emerging as an attractive catalyst for water splitting due to their excellent activity and stability.However,most of the MoP synthesized so far are crystalline MoP with relatively fewer exposed active sites and low electrical conductivity.Here,we use a metallo-organic Mo precursor(MoO_(2)(acac)_(2))to create defect-rich crystalline MoP nanoparticles and uniformly anchor them on reduced graphene oxide(denoted as D-MoP/rGO).High-temperature thermal decomposition of the precursor generates gases,which induce a variety of defects in D-MoP/rGO along with a P-rich surface composition.The electrochemically active surface area of D-MoP/rGO is 8 times that of bulk MoP.D-MoP/rGO requires a small overpotential of 122 mV for the hydrogen evolution reaction(HER)to reach a current density of 10 mA cm^(-2).Furthermore,density functional theory(DFT)calculation results reveal that surface P sites are the key active sites,which favor the adsorption of H atoms and also act as an H deliverer to promote the HER.Importantly,D-MoP/rGO is also a highly active catalyst for the hydrazine oxidation reaction(HzOR)and requires a low overpotential of 84 mV to reach a current density of 10 mA cm^(-2).Thus,efficient HER||HzOR hybrid water-splitting can be realized using D-MoP/rGO,which can deliver a current density of 100 mA cm^(-2)at a small cell voltage of 0.74 V and undergo a stable 12 h operation.In summary,a simple method has been demonstrated to generate high-performance metal phosphide electrocatalysts for total water splitting.Furthermore,the material design concept of creating defective crystalline nanoparticles using gas generating metal precursors can serve as a general approach to create various catalytic active defective crystalline materials.
基金financially supported by the National Natural Science Foundation of China (No. 21972126, 21978264, 21905250, and 22278369)the Natural Science Foundation of Zhejiang Province (No. LQ22B030012 and LQ23B030010)the China Postdoctoral Science Foundation (2021M702889)。
文摘Utilizing the hydrazine-assisted water electrolysis for energy-efficient hydrogen production shows a promising application, which relies on the development and design of efficient bifunctional electrocatalysts. Herein, we reported a low-content Pt-doped Rh metallene(Pt-Rhene) for hydrazine-assisted water electrolysis towards energy-saving hydrogen(H_(2)) production, where the ultrathin metallene is constructed to provide enough favorable active sites for catalysis and improve atom utilization.Additionally, the synergistic effect between Rh and Pt can optimize the electronic structure of Rh for improving the intrinsic activity. Therefore, the required overpotential of Pt-Rhene is only 37 mV to reach a current density of-10 mA cm^(-2) in the hydrogen evolution reaction(HER), and the Pt-Rhene exhibits a required overpotential of only 11 mV to reach a current density of 10 mA cm^(-2) in the hydrazine oxidation reaction(HzOR). With the constructed HER-HzOR two-electrode system, the Pt-Rhene electrodes exhibit an extremely low voltage(0.06/0.19/0.28 V) to achieve current densities of 10/50/100 mA cm^(-2) for energy-saving H_(2) production, which greatly reduces the electrolysis energy consumption. Moreover,DFT calculations further demonstrate that the introduction of Pt modulates the electronic structure of Rh and optimizes the d-band center, thus enhancing the adsorption and desorption of reactant/intermediates in the electrocatalytic reaction.
基金financially supported by the National Natural Science Foundation of China(52371222,52271211,52303341)the Natural Science Foundation of Hunan Province in China(2025JJ60350,2023JJ50043)+1 种基金Key Research and Development Program of Hunan Province(2023GK2035)HORIZON EUROPE Marie Sklodowska-Curie Actions-2021(101065098)。
文摘The hydrazine oxidation-assisted hydrogen generation system significantly expands the applicability of hydrogen production technology.However,the complex intermediate transformations involved in the hydrazine oxidation reaction(HzOR)and hydrogen evolution reaction(HER)desperately need the development of dual-functional catalysts.Manipulating the d-band center of metal catalysts has been identified as one of the most effective approaches to enhance catalytic activity.Herein,Ir nanoparticles(NPs)anchored in B,N-codoped porous carbon(Ir@BNC)were developed and demonstrate excellent performances for both HER and HzOR in an alkaline medium,achieving 10 mA cm^(-2) at-25 and 18 mV,respectively.The overall hydrazine splitting(OHzS)electrolyzer reaches 200 mA cm^(-2) with a cell voltage of just 0.68 V.The direct liquid N2H4/H2O_(2) fuel cell(DHHPFC)assembly with Ir@BNC can achieve a maximum power density of 199.2 mW cm^(-2) at room temperature.Furthermore,an H2 production system using an OHzS device powered by DHHPFC realizes hydrogen production at a stable rate(53.08 mol h^(-1) m^(-2)).In-situ Raman tests and theoretical calculations unravel the metal-support interaction between Ir NPs and B,N-codoped porous carbon,optimizing the electronic structure and regulating the d-band center of Ir,reducing the adsorption energy of H*intermediates and N2H4 molecules,thus promoting the reaction processes of HER and HzOR.
基金supported by the National Natural Science Foundation of China(22272103)the National Natural Science Foundation of China for the Youth(22309108,22202076)+3 种基金the Science and Technology Innovation Team of Shaanxi Province(2023-CX-TD-27)the China Postdoctoral Science Foundation(2023TQ0204)the Young Scientist Initiative Project of School of Materials Science and Engineering at Shaanxi Normal University(2024YSIP-MSE-SNNU008)Sanqin Scholars Innovation Teams in Shaanxi Province in China.
文摘Metallene has been widely considered as an advanced electrocatalytic material due to its large specific surface area and highly active reaction sites.Herein,we design and synthesize ultrathin rhodium metallene(Rh ML)with abundant wrinkles to supply surface-strained Rh sites for driving acetonitrile electroreduction to ethylamine(AER).The electrochemical tests indicate that Rh ML shows an ethylamine yield rate of 137.1 mmol gcat^(-1) h^(-1) in an acidic solution,with stability lasting up to 200 h.Theoretical calculations reveal that Rh ML with wrinkle-induced compressive strain not only shows a lower energy barrier in the rate-determining step but also facilitates the ethylamine desorption process compared to wrinkle-free Rh ML and commercial Rh black.The assembled electrolyzer with bifunctional Rh ML shows an electrolysis voltage of 0.41 V at 10 mA cm^(-2),enabling simultaneous ethylamine production and hydrazine waste treatment.Furthermore,the voltage of an assembled hybrid zinc-acetonitrile battery can effectively drive this electrolyzer to achieve the dual AER process.This study provides guidance for improving the catalytic efficiency of surface atoms in two-dimensional materials,as well as the electrochemical synthesis technology for series-connected battery-electrolyzer systems.
基金the National Natural Science Foundation of China(U21A20286 to Y.H.,22206054 to Y.H.,and 22478310 to J.Z.)the Fundamental Research Funds for the Central China Normal University(CCNU)。
文摘Hydrogen peroxide(H_(2)O_(2))production via electrochemical two-electron oxygen reduction reaction(ORR)holds a great promise for sustainable energy storage.However,the issues such as high energy consumption and difficult extraction of thermodynamically unstable H_(2)O_(2) still need to be resolved.Herein,we reported a unified system for energy-out production and downstream conversion of H_(2)O_(2).By replacing the sluggish oxygen evolution reaction with a hydrazine oxidation reaction(HzOR),the cell of twoelectron ORR coupled with HzOR achieves the co-generation of electricity energy and valuable H_(2)O_(2).By employing Ru single atoms anchored on cobalt hydroxide(for HzOR)and NiSe_(2)(for ORR)as electrocatalysts,both exhibiting onset potentials near the theoretical values for their respective reactions,the ORR‖HzOR cell exhibits an energy output of 3.58 mW cm^(-2) and generates 0.66 kWh of electricity per kg of H_(2)O_(2).with a production rate of 583 mmol h^(-1) H_(2)O_(2).The produced H_(2)O_(2) was subsequently in-situ upgraded via three downstream conversion pathways to yield value-added products of sodium percarbonate,sodium peroxyborate,and ethylene glycol.A techno-economic analysis confirmed the economic viability of this ORR‖HzOR coupled with downstream conversion system.
基金supported by the National Natural Science Foundation of China(Nos.51772162 and 52072197)the Outstanding Youth Foundation of Shandong Province,China(No.ZR2019JQ14)+3 种基金the Youth Innovation and Technology Foundation of Shandong Higher Education Institutions,China(No.2019KJC004)the Major Scientific and Technological Innovation Project(No.2019JZZY020405)the Major Basic Research Program of Natural Science Foundation of Shandong Province(No.ZR2020ZD09)the Taishan Scholar Young Talent Program(No.tsqn201909114).
文摘Seawater electrolysis could address the water scarcity issue and realize the grid-scale production of carbon-neutral hydrogen,while facing the challenge of high energy consumption and chloride corrosion.Thermodynamically more favorable hydrazine oxidation reaction(HzOR)assisted water electrolysis is efficiency for energy-saving and chlorine-free hydrogen production.Herein,the MoNi alloys supported on MoO_(2) nanorods with enlarged hollow diameter on Ni foam(MoNi@NF)are synthesized,which is constructed by limiting the outward diffusion of Ni via annealing and thermal reduction of NiMoO_(4) nanorods.When coupling HzOR and hydrogen evolution reaction(HER)by employing MoNi@NF as both anode and cathode in two-electrode seawater system,a low cell voltage of 0.54 V is required to achieve 1,000 mA·cm^(−2) and with long-term durability for 100 h to keep above 100 mA·cm^(−2) and nearly 100%Faradaic efficiency.It can save 2.94 W·h to generate per liter H_(2) relative to alkaline seawater electrolysis with 37%lower energy equivalent input.
文摘Copper nanoparticles-decorated polyaniline- derived mesoporous carbon that can serve as noble metal-free electrocatalyst for the hydrazine oxidation reaction （HzOR） is synthesized via a facile synthetic route. The material exhibits excellent electrocatalytic activity toward HzOR with low overpotential and high current density. The material also remains stable during the electrocatalytic reaction for long time. Its good electro- catalytic performance makes this material a promising alternative to conventional noble metal-based catalysts （e.g., Pt） that are commonly used in HzOR-based fuel cells.
基金This work is supported by the National Natural Science Foundation of China(No.21872040)the Hundred Talents Program of Guangxi Universities,the Excellent Scholars and Innovation Team of Guangxi Universities,Guangxi Major Projects of Science and Technology(No.GXMPSTAA17202032),Guangxi Ba-Gui Scholars Program.
文摘Developing high performance anode catalysts for oxygen evolution reaction (OER) and hydrazine oxidation reaction (HzOR) at large current density is an efficient pathway to produce hydrogen. Herein, we synthesize a FeWO_(4)-WO_(3) heterostructure catalyst growing on nickel foam (FeWO_(4)-WO_(3)/NF) by a combination of hydrothermal and calcination method. It shows good catalytic activity with ultralow potentials for OER (ζ_(10) = 1.43 V, ζ_(1.000) = 1.56 V) and HzOR (ζ_(10) = −0.034 V, ζ_(1.000) = 0.164 V). Moreover, there is little performance degradation after being tested for _(10)0 h at 1,000 (OER) and _(10)0 (HzOR) mA·cm−2, indicating good stability. The superior performance could be attributed to the wolframite structure and heterostructure: The former provides a high electrical conductivity to ensure the electronic transfer capability, and the later induces interfacial electron redistribution to enhance the intrinsic activity and stability. The work offers a brand-new way to prepare good performance catalysts for OER and HzOR, especially at large current density.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry ofEducation(2021R1A2C3011870 and 2019R1A6A1A03033215)the Korea Research Fellowship Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2020H1D3A1A04081323)
文摘Rh has been widely studied as a catalyst for the promising hydrazine oxidation reaction that can replace oxygen evolution reactions for boosting hydrogen production from hydrazine-containing wastewater.Despite Rh being expensive,only a few studies have examined its electrocatalytic mass activity.Herein,surface-limited cation exchange and electrochemical activation processes are designed to remarkably enhance the mass activity of Rh.Rh atoms were readily replaced at the Ni sites on the surface of NiOOH electrodes by cation exchange,and the resulting RhOOH compounds were activated by the electrochemical reduction process.The cation exchange-derived Rh catalysts exhibited particle sizes not exceeding 2 nm without agglomeration,indicating a decrease in the number of inactive inner Rh atoms.Consequently,an improved mass activity of 30 A mg_(Rh)^(-1)was achieved at 0.4 V versus reversible hydrogen electrode.Furthermore,the two-electrode system employing the same CE-derived Rh electrodes achieved overall hydrazine splitting over 36 h at a stable low voltage.The proposed surface-limited CE process is an effective method for reducing inactive atoms of expensive noble metal catalysts.
基金financially supported by the National Natural Science Foundation of China(No.22302103)the Natural Science Foundation of Jiangsu Province(No.BK20230619)+1 种基金the Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.23KJB540003)the Science Research Program of Nantong University(No.03083110)。
文摘Electrolyzing seawater is a promising solution to produce hydrogen,which is hindered by low-efficiency oxygen evolution reaction(OER)and noxious chloride chemistry.Herein,the Fe-Co_(2)P/CeO_(2)heterostructure nanosheet arrays are developed to achieve energy-saving and chlorine-free hydrogen generation by coupling hydrogen evolution reaction(HER)with hydrazine oxidation reaction(HzOR)in seawater.The Fe-Co_(2)P/CeO_(2)realizes current densities of 10 and 400 mA·cm^(-2)at 52 and204 mV for HER.The anode potential is significantly decreased after replacing OER with HzOR.Theoretical calculations display that the electronic structure of Fe-Co_(2)P can be regulated after coupling CeO_(2),which lowers the water dissociation barrier and optimizes hydrogen adsorption-free energy,thus boosting catalytic kinetics.Significantly,the hybrid seawater electrolyzer produces hydrogen at ultralow cell voltages,greatly reducing traditional water electrolysis voltages and avoiding hazardous chlorine chemistry.This study provides an avenue to exploit advanced catalysts for acquiring hydrogen with energy-efficiency and chlorine-free from abundant ocean.
基金support was provided by the National Key Research and Development Program of China,Grant/Award Number:2023YFB4203900the Fundamental Research Funds for the Central Universities,Grant/Award Number:226‐2024‐00075.
文摘Direct hydrazine‐hydrogen peroxide fuel cells(DHzHPFCs)offer unique advantages for air‐independent applications,but their commercialization is impeded by the lack of high‐performance and low‐cost catalysts.This study reports a novel dual‐site Co‐Zn catalyst designed to enhance the hydrazine oxidation reaction(HzOR)activity.Density functional theory calculations suggested that incorporating Zn into Co catalysts can weaken the binding strength of the crucial N_(2)H_(3)*intermediate,which limits the ratedetermining N_(2)H_(3)*desorption step.The synthesized p‐Co_(9)Zn1 catalyst exhibited a remarkably low reaction potential of−0.15 V versus RHE at 10mAcm−2,outperforming monometallic Co catalysts.Experimental and computational analyses revealed dual active sites at the Co/ZnO interface,which facilitate N_(2)H_(3)*desorption and subsequent N_(2)H_(2)*formation.A liquidN_(2)H_(4)‐H_(2)O_(2)fuel cell with p‐Co_(9)Zn1 catalyst achieved a high open circuit voltage of 1.916 V and a maximum power density of 195mWcm^(−2),demonstrating the potential application of the dual‐site Co‐Zn catalyst.This rational design strategy of tuning the N_(2)H_(3)*binding energy through bimetallic interactions provides a pathway for developing efficient and economical non‐precious metal electrocatalysts for DHzHPFCs.
基金supported by the National Natural Science Foundation of China(Grant Nos.51971157 and 22075211)Shenzhen Science and Technology Program(Grant Nos.JCYJ20210324115412035,JCYJ20210324123202008,JCYJ20210324122803009 and ZDSYS20210813095534001)Guangdong Foundation for Basic and Applied Basic Research Program(Grant No.2021A1515110880).
文摘Layered double hydroxides have demonstrated great potential for the oxygen evolution reaction,which is a crucial half-reaction of overall water splitting.However,it remains challenging to apply layered double hydroxides in other electrochemical reactions with high efficiency and stability.Herein,we report two-dimensional multifunctional layered double hydroxides derived from metalorganic framework sheet precursors supported by nanoporous gold with high porosity,which exhibit appealing performances toward oxygen/hydrogen evolution reactions,hydrazine oxidation reaction,and overall hydrazine splitting.The as-prepared catalyst only requires an overpotential of 233 mV to reach 10 mA·cm^(-2) toward oxygen evolution reaction.The overall hydrazine splitting cell only needs a cell voltage of 0.984 V to deliver 10 mA·cm^(-2),which is far more superior than that of the overall water splitting system(1.849 V).The appealing performances of the catalyst can be contributed to the synergistic effect between the metal components of the layered double hydroxides and the supporting effect of the nanoporous gold substrate,which could endow the sample with high surface area and excellent conductivity,resulting in superior activity and stability.
基金supported by the National Natural Science Foundation of China(22179065)the Ph.D.Candidate Research Innovation Fund of NKU School of Materials Science and Engineering.
文摘The hydrazine oxidation reaction(HzOR)boasts a low theoretical working potential,rendering it promising for applications in energy-saving hydrogen production and treatment of hydrazine-containing wastewater.Herein,Ni species-incorporated CoP nanosheet arrays encapsulated in N-doped carbon layers grown on Ni foam(Ni-CoP@NC)have been synthesized.Due to the outstanding synergistic effect resulting from metal incorporation and N-doped carbon encapsulation,a high current density of 1 A cm^(-2)at low potentials of-143 mV and 51 mV for the hydrogen evolution reaction(HER)and HzOR is achieved by using Ni-CoP@NC,respectively.Furthermore,the Ni-CoP@NC-assembled hydrazine-assisted seawater electrolysis system exhibits a remarkable decrease in voltage input compared to conventional and other hybrid electrolysis devices,achieving an ultra-low voltage of just 0.49 V to attain a current density of 1 A cm^(-2).Remarkably,a five-fold cost reduction is offered by this system compared to conventional water electrolysis.Moreover,a novel multi-powered hydrogen production system is proposed,which consists of renewable energy sources,direct hydrazine fuel cells,rechargeable Zn-hydrazine batteries,and hydrazine-assisted seawater electrolysis.This system showcases the unique advantages of the HzOR and its potential contribution to electrochemical energy conversion technologies for sustainable energy supply.
基金supported by the National Natural Science Foundation of China(22205205)the Zhejiang Provincial Natural Science Foundation of China(LQ22B030008)the Science Foundation of Zhejiang Sci-Tech University(ZSTU)under Grant No.21062337-Y.
文摘Coupling the thermodynamically favorable hydrazine oxidation reaction(HzOR)with the hydrogen evolution reaction(HER)in a hybrid water electrolyzer is an effective strategy to improve the energy efficiency of large-scale high-purity H2 production,while achieving pollutant degradation.Recently,various advanced materials have been exploited as electrocatalysts for hydrazine-assisted water electrolysis,but a fundamental understanding of them and a comprehensive summary are lacking to date.In this review,we provide a comprehensive review of advanced electrocatalysts available for HzOR-assisted water electrolysis,as well as various regulatory strategies based on precious metals and non-noble metal-based materials,such as doping,heterostructures,single-atoms,and alloying.Moreover,the structure-activity relationship including electronic structure,surface properties,and catalytic performance of the electrocatalysts is systematically discussed.Given the importance and unique advantages of direct hydrazine hydrate-assisted seawater electrolysis and self-powered electrolyzers,we also present systematic summaries of material design,performance evaluation,and mechanism studies.Finally,several key challenges and future perspectives about hydrazine-assisted water electrolysis are discussed to offer insight into large-scale H2 production for energy-saving pathways.
基金supported by the National Natural Science Foundation of China(22179065 and 21875118)the Smart Sensing Interdisciplinary Science Center,Nankai University.
文摘Electrochemical overall water splitting for sustainable hydrogen generation is severely hindered by anode water electrooxidation with sluggish kinetics.Thus,using the thermodynamically favorable hydrazine oxidation reaction(HzOR)to substitute the oxygen evolution reaction(OER)has attracted ever-growing attention.Herein,well-defined copper selenide nanoflakes,in situ grown on copper foam(termed Cu_(x)Se/CF),were synthesized by a one-step selenization strategy,which are composed of nonstoichiometric Cu_(2-x)Se with stable Cu2Se berzelianite that show remarkable bifunctional activities for the hydrogen evolution reaction(HER)and HzOR electrocatalysis.Investigations into the mechanisms uncovered that the high copper deficiencies in the Cu_(2-x)Se phase make it both an excellent electron donor and acceptor,leading to faster electron transfers across the catalyst(electrode)-electrolyte interface,which greatly boosts the reaction kinetics of HER and HzOR processes.Meanwhile,the Cu2Se berzelianite phase plays a pivotal role in the long-term electrocatalytic operation for the HER and HzOR.Encouraged by this synergistic advantage,the CuxSe/CF catalysts were further employed as good bifunctional catalysts for electrocatalytic hydrazine-assisted overall water splitting with a low cell voltage of 0.49 V at 25 mA cm^(-2),as well as having good stability over 20 h,which indicates the broad potential for future industrialization of a sustainable hydrogen-based society.
基金financially supported by the National Natural Science Foundation of China(22075211,21601136,51971157,62005173,and 51621003)the Zhejiang Provincial Natural Science Foundation of China(LR19B060002)+5 种基金the Research Funds of Institute of Zhejiang University-QuzhouThe Guangdong Province Higher Vocational Colleges&Schools Pearl River Scholar Funded Scheme(2016)the Guangdong Third Generation Semiconductor Engineering Technology Development Center(2020GCZX007)the Science,Technology,and Innovation Commission of Shenzhen Municipality(RCBS20200714114818140)the China Postdoctoral Science Foundation(2019M663118)the School level Scientific Research Project of Shenzhen Institute of Information Technology(PT2019E002).
文摘Electrochemical H_(2) production from water splitting is an environmentally sustainable technique but remains a great challenge due to the sluggish anodic oxygen evolution reaction(OER).Replacing the OER with the thermodynamically more favorable electrocatalytic oxidation process is an effective strategy for highly efficient H_(2) generation.Herein,Mn-doped CoS_(2) has predicted an excellent bifunctional electrocatalyst for the hydrogen evolution reaction(HER)and the hydrazine oxidation reaction(HzOR).With the introduction of Mn,the Gibbs free energy of the adsorbed H* and the potential rate-limiting step(the dehydrogenation of *NH_(2)NH_(2) to *NHNH_(2))for the HzOR process of the catalyst can be significantly reduced.As expected,the Mn-CoS_(2) catalyst exhibited excellent catalytic activity and robust long-term stability for the HER and HzOR.In detail,the Mn-CoS_(2) catalyst only acquired potentials of 46 and 77 mV versus the reversible hydrogen electrode for achieving a current density of 10 mA cm^(-2) for the cathodic HER and anodic HzOR,respectively.In addition,the Mn-CoS_(2) electrode only needs a cell voltage of 447 mV to output 200 mA cm^(-2) in the overall hydrazine splitting system as well as exhibits a robust longterm H_(2) production.This work provides theoretical guidance for the design of advanced bifunctional electrocatalysts and promotes high efficiency and energy-saving H_(2) production technology.
