In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry bet...In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry between corresponding building blocks and linking units in addition to the unmanageable packing of 1D organic chains once formed.Herein,two novel imide-linked 1D COFs with phthalocyanine building blocks,namely NiPc-CZDM-COF and NiPc-CZDL-COF,were fabricated from the hydrothermal synthesis reaction of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato nickel(II)(NiPc(COOH)_(8))with 9H-carbazole-3,6-diamine(CZDM)and 4,4′-(9H-carbazole-3,6-diyl)dianiline(CZDL),respectively.Two COFs have high crystallinity on the basis of powder X-ray diffraction analysis and high-resolution transmission electron microscopy.Due to their high ratio of exposed active centers on the edge sites of porous ribbons,both NiPc-CZDM-COF and NiPc-CZDL-COF electrodes display high utilization efficiency of NiPc electroactive sites of 8.0%and 7.5% according to the electrochemical measurement,resulting in their excellent capacity toward electrocatalytic nitrate reduction with the nitrate-to-NH3 Faradaic efficiency of nearly 100%.In particular,NiPc-CZDM-COF electrode exhibits superior electrocatalytic performance with high NH3 partial current density of−246 mA/cm^(2),ammonia yield rate of 19.5 mg cm^(−2) h^(−1),and turnover frequency of 5.8 s^(−1) at−1.2 V in an H-type cell associated with its higher conductivity.This work reveals the good potential of 1D porous crystalline materials in electrocatalysis.展开更多
Ammonia is the cornerstone of modern agriculture,providing a critical nitrogen source for global food production and serving as a key raw material for numerous industrial chemicals.Electrocatalytic nitrate reduction,a...Ammonia is the cornerstone of modern agriculture,providing a critical nitrogen source for global food production and serving as a key raw material for numerous industrial chemicals.Electrocatalytic nitrate reduction,as an environmentally friendly method for synthesizing ammonia,not only mitigates the reliance on current ammonia synthesis processes fed by traditional fossil fuels but also effectively reduces nitrate pollution resulting from agricultural and industrial activities.This review explores the fundamental principles of electrocata lytic nitrate reduction,focusing on the key steps of electron transfer and ammonia formation.Additionally,it summarizes the critical factors influencing the performance and selectivity of the reaction,including the properties of the electrolyte,operating voltage,electrode materials,and design of the electrolytic cell.Further discussion of recent advances in electrocatalysts,including pure metal catalysts,metal oxide catalysts,non-metallic catalysts,and composite catalysts,highlights their significant roles in enhancing both the efficiency and selectivity of electrocata lytic nitrate to ammonia(NRA)reactions.Critical challenges for the industrial NRA trials and further outlooks are outlined to propel this strategy toward real-world applications.Overall,the review provides an in-depth overview and comprehensive understanding of electrocata lytic NRA technology,thereby promoting further advancements and innovations in this domain.展开更多
Electrocatalytic nitrate reduction reaction (NO_(3)-RR) to ammonia under ambient conditions is expected to be a green process for ammonia synthesis and alleviate water pollution issues.We report a CuO nanoparticles in...Electrocatalytic nitrate reduction reaction (NO_(3)-RR) to ammonia under ambient conditions is expected to be a green process for ammonia synthesis and alleviate water pollution issues.We report a CuO nanoparticles incorporated on nitrogen-doped porous carbon (CuO@NC) catalyst for NO_(3)-RR.Part of Cu(Ⅱ) is reduced to Cu(Ⅰ) during the NO_(3)-RR process to construct Cu(Ⅰ)-Cu(Ⅱ) pairs,confirmed by in situ X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.Density functional theory (DFT) calculations indicated that the formation of Cu(Ⅰ) could provide a reaction path with smaller energy barrier for NO_(3)-RR,while Cu(Ⅱ) effectively suppressed the competition of hydrogen evolution reaction (HER).As a result,CuO@NC catalyst achieved a Faradaic efficiency of 84.2% at -0.49 V versus reversible hydrogen electrode (RHE),and a NH_(3)yield rate of 17.2 mg h^(-1)mg^(-1)cat.at -0.79 V vs.RHE,higher than the HaberBosch process (<3.4 g h^(-1)g^(-1)cat.).This work may open a new avenue for effective NO_(3)-RR by modulating oxidation states.展开更多
The electrochemical conversion of nitrate,a widespread water pollutant,into valuable ammonia represents a green and decentralized approach to ammonia synthesis.However,the sluggish multielectronproton coupling path an...The electrochemical conversion of nitrate,a widespread water pollutant,into valuable ammonia represents a green and decentralized approach to ammonia synthesis.However,the sluggish multielectronproton coupling path and the low reactive species(nitrate and proton)concentration at the catalyst interface inhibit the efficiency of ammonia production from nitrate reduction reaction(NitRR).Herein,we introduce a novel iron-based tandem catalyst encapsulated by reduced graphene oxide(denoted as Fe-rGO),with a superior ammonia production rate of 47.815 mg h^(-1)mg_(ca)^(t-1)and a high Faraday efficiency(FE)of 96.51%at an applied potential of-0.5 V.It also delivers a robust stability with FE above90%under a current density of 250 mA cm^(-2)for 50 h.In situ X-ray absorption spectroscopy reveals that the FeO_(x)is dynamically translated to Fe~0 site concurrently with the enhancement of the NH_(3)production rate,suggesting the Fe^(0) site as hydrogenation active center.The asymmetric distribution of surface charges of rGO not only enriches nitrate ions at the catalytic interface and promotes the hydrogenation process in NitRR,but also protects the iron species and ensures their stability during electrolysis.The Zn-NO_(3)^(-)battery demonstrates an impressive FE of 88.6%,highlighting its exceptional potential for practical applications.展开更多
Electrocatalytic reduction of nitrate to ammonia offers an environmentally friendly and sustainable approach for ammonia production,but it involves a multi-step reaction process with complex intermediates,and still fa...Electrocatalytic reduction of nitrate to ammonia offers an environmentally friendly and sustainable approach for ammonia production,but it involves a multi-step reaction process with complex intermediates,and still faces the challenge of high activity and high selectivity.Herein,a high-entropy nanoalloy was synthesized via high-temperature annealing of metal salt with dopamine as a carbon source for electrocatalytic reduction of nitrate to ammonia.The FeCoNiCuRu_(1.5)/C catalyst displays a conversion rate of 90.2%and an ammonia selectivity of 92.2% at-0.74 V(vs.RHE),significantly surpassing the performance of lowentropy alloys such as FeCo/C by 1.5–2 times.Moreover,FeCoNiCuRu_(1.5)/C maintains a consistent nitrate conversion rate of about 90.0% after 120 h of continuous operation(10 cycles),indicating high stability.The superior performance of FeCoNiCuRu_(1.5)/C can be attributed to the synergetic relay catalysis among Fe,Co,Ni,Cu,and Ru sites.This synergy enhances nitrate adsorption due to the optimized electronic structure of multiple active sites,which facilitates the nitrate reduction to intermediates.Subsequently,the effective active hydrogen produced at the Ru site,in conjunction with adjustments at other metal sites,promotes the selective transformation of the intermediates into ammonia.This work not only highlights the efficacy of synergetic relay electrocatalysis but also opens new avenues for developing highly efficient multi-site catalysts.展开更多
Red mud(RM)is a solid waste generated in the aluminum industry after the extraction of alumina oxide;its multiple elements and higher pH value likely pose a severe threat to the environment after treatment.However,RM&...Red mud(RM)is a solid waste generated in the aluminum industry after the extraction of alumina oxide;its multiple elements and higher pH value likely pose a severe threat to the environment after treatment.However,RM's higher concentrations of metal components,particularly Fe_(2)O_(3)and rare earth elements(REEs),render RM promising for catalytic application.Hence,this work showed an efficient high-speed RM to catalyze electrocatalytic nitrate-to-ammonia reduction reaction(NARR).RM calcined at 500℃(RM-500)exhibited excellent catalytic performance.Faradaic efficiency of ammonia(FENH_(3))in an electrolyte solution containing 1 mol·L^(-1)NO_(3)-achieved a maximum value of 92.3%at-0.8 V(vs.RHE).Additionally,24-h cycle testing and post-reaction PXRD and SEM indicated that the RM-500 electrocatalyst is stable during NARR.The RM-500 demonstrated a high FE of NH_(3)-to-NO_(3)-of 89.7%at 1.85 V(vs.RHE),showing great potential in the ammonia fuel cells technology and achieving the nitrogen cycle.展开更多
In this work,an effective catalyst of Cu/MnOOH has been successfully constructed for electrochemical nitrate reduction reaction(e NO_(3)RR)for synthesis of ammonia(NH_(3))under ambient conditions.The substrate of MnOO...In this work,an effective catalyst of Cu/MnOOH has been successfully constructed for electrochemical nitrate reduction reaction(e NO_(3)RR)for synthesis of ammonia(NH_(3))under ambient conditions.The substrate of MnOOH plays an important role on the size and electronic structure of Cu nanoparticles,where Cu has the ultrafine size of 2.2 nm and positive shift of its valence states,which in turn causes the increased number of Cu active sites and enhanced intrinsic activity of every active site.As a result,this catalyst realizes an excellent catalytic performance on eNO_(3)RR with the maximal NH_(3)Faraday efficiency(FE)(96.8%)and the highest yield rate(55.51 mg h^(-1)cm^(-2))at a large NH_(3)partial current density of700 m A/cm^(2),which could help to promote the industrialization of NH_(3)production under ambient conditions.展开更多
The efficient electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NRA)offers a sustainable alternative for both environmental remediation and ammonia synthesis.Developing advanced electrocatalysts with rationally...The efficient electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NRA)offers a sustainable alternative for both environmental remediation and ammonia synthesis.Developing advanced electrocatalysts with rationally designed spatial arrangement of active sites and optimizing the synergetic effect among components are crucial for high efficiency and selectivity.Herein,we present Fe/N active sites decorated on porous carbon nanofibers(CNFs)with encapsulated FeCo nanoparticles(FeCo@CNFs-Fe/N)as electrocatalysts for NRA.The FeCo@CNFs-Fe/N catalyst demonstrates exceptional performance,achieving a high ammonia yield of 498.18μmol/(h·g_(cat)).Meanwhile,the enhanced reduction activity,especially the reduction in overpotential by 0.565 V,is 3–10 times higher than that of FeCo-encapsulated and Fe/N-modified CNFs-based catalysts.The enhanced catalytic activity is attributed to the efficient structure design and optimized spatial distribution of active sites,which enhance the electron transfer rate and decrease the reaction energy barrier.Mechanistic studies reveal that the synergetic effect between encapsulated nanoparticles and surface-modified Fe/N sites plays a crucial role in promoting efficient nitrate adsorption and selective ammonia production.These findings highlight the potential of strategically engineered CNF-based composites for nitrate reduction and other advanced electrocatalytic applications.展开更多
The excess emission of nitrate from human activities disturbs the global nitrogen cycle and thus needs to be remediated.In this work,we prepared a La-doped Co_(3)O_(4)nanoneedle arrays catalyst for highly efficient el...The excess emission of nitrate from human activities disturbs the global nitrogen cycle and thus needs to be remediated.In this work,we prepared a La-doped Co_(3)O_(4)nanoneedle arrays catalyst for highly efficient electrocatalytic reduction of NO_(3)^(-) to NH_(3)at low concentration.The La-doped Co_(3)O_(4)nanoneedle arrays exhibit remarkable activity with the highest Faradaic efficiency of 95.5%and an ammonia yield rate of 4.08 mg/(h·cm^(2))at-0.3 V versus RHE in 0.02 mol/L NO_(3)^(-).Experiments and theoretical calculations show that the La doping not only facilitates the surface reconstruction to form active La-Co(OH)_(2),but also inhibits the hydrogen evolution reaction over Co sites,thus promoting the NH_(3)production.This work provides new insights into the promoting effect of the rare earth elements in transition metalbased electrocatalyst for nitrate reduction.展开更多
Catalytic reduction of nitrate over bimetallic catalysts has emerged as a technology for sustainable treatment of nitrate-containing groundwater.However,the structure of bimetallic has been much less investigated for ...Catalytic reduction of nitrate over bimetallic catalysts has emerged as a technology for sustainable treatment of nitrate-containing groundwater.However,the structure of bimetallic has been much less investigated for catalyst optimization.Herein,two main types of Pd-Cu bimetallic nanocrystal structures,heterostructure and intermetallic,were prepared and characterized using high-resolution transmission electron microscopy(HRTEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The results show that two individual Pd and Cu nanocrystals with a mixed interface exist in the heterostructure nanocrystals,while Pd and Cu atoms are uniformly distributed across the intermetallic Pd-Cu nanocrystals.The catalytic nitrate reduction experiments were carried out in a semibatch reactor under constant hydrogen flow.The nitrate conversion rate of the heterostructure Pd-Cu nanocrystals supported onα-Al_(2)O_(3),γ-Al_(2)O_(3),SBA-15,and XC-72R exhibited 3.82-,6.76-,4.28-,2.44-fold enhancements relative to the intermetallic nanocrystals,and the nitrogen and nitrite were the main products for the heterostructure and intermetallic Pd-Cu nanocrystals,respectively.This indicates that the catalytic nitrate reduction over Pd-Cu catalyst is sensitive to the bimetallic structures of the catalysts,and heterostructure bimetallic nanocrystals exhibit better catalytic performances on both the activity and selectivity,which may provide new insights into the design and optimization of catalysts to improve catalytic activity and selectivity for nitrate reduction in water.展开更多
Electrochemical nitrate reduction(NO_(3)RR)offers a promising avenue for treating nitrate-contaminated water and recovering ammonia(NH_(3)),yet the complexities of direct electron transfer(DET)and hydrogen atom transf...Electrochemical nitrate reduction(NO_(3)RR)offers a promising avenue for treating nitrate-contaminated water and recovering ammonia(NH_(3)),yet the complexities of direct electron transfer(DET)and hydrogen atom transfer(HAT)mechanisms crucial for efficiency remain elusive.This study bridges the gap with a combined experimental and theoretical approach,elucidating the impact of catalyst structure on NO3RR pathways.We discover that catalysts favoring strong NO_(3^(-))adsorption and efficient water dissociation were more inclined towards DET,enhancing denitrification.The Fe@Fe_(3)O_(4)/FF cathode,leveraging the synergistic interplay between metallic Fe and Fe_(3)O_(4),excelled in NO3RR via DET,achieving an NH3yield of 0.28 mmol h-1cm-2and a Faradaic efficiency of 95.7%for NH3at-1.6 V(vs.SCE),with minimal nitrite accumulation at 100 mmol/L nitrate.Conversely,the Fe/FF and Fe_(3)O_(4)/CC cathodes showed reduced NH3production and increased nitrite levels,attributed to the lack of Fe_(3)O_(4)and metallic Fe,respectively,resulting in a dominant HAT mechanism.Moreover,Fe@Fe_(3)O_(4)/FF facilitated complete denitrification in real wastewater treatment by harnessing Cl^(-)for electrochemically mediated breakpoint chlorination.This research not only deepens our understanding of NO3RR mechanisms but also paves the way for designing superior nitrate reduction catalysts.展开更多
Electrocatalytic nitrate reduction reaction(NitRR)utilizing water as a hydrogen source under ambient conditions represents a highly promising avenue for sustainable ammonia synthesis and environmental remediation.Howe...Electrocatalytic nitrate reduction reaction(NitRR)utilizing water as a hydrogen source under ambient conditions represents a highly promising avenue for sustainable ammonia synthesis and environmental remediation.However,achieving high efficiency and selectivity in NitRR is fundamentally challenged by the complex lifecycle management of active hydrogen derived from water splitting.This review provides a timely and comprehensive analysis centered on the pivotal role and meticulous regulation of active hydrogen throughout the NitRR process.We first elucidate the distinct functions and characteristics of various hydrogen species,followed by a survey of advanced characterization techniques crucial for monitoring the dynamics of active hydrogen.Critically,three core strategies were systematically dissected to modulate the active hydrogen lifecycle:accelerating water activation and dissociation,enhancing the directional transport of hydrogen species,and precisely tuning active hydrogen coupling pathways while suppressing parasitic hydrogen evolution.By consolidating current understanding from both catalyst design and reaction mechanism perspectives,this review offers a hydrogen-centric roadmap and highlights emerging opportunities for rationally engineering advanced NitRR systems.展开更多
Electrochemical nitrate(NO_(3)^(-))reduction reaction(eNO_(3)RR)presents a promising and sustainable strategy for converting environmentally hazardous NO_(3)^(-)into value-added ammonia(NH3),thereby addressing both po...Electrochemical nitrate(NO_(3)^(-))reduction reaction(eNO_(3)RR)presents a promising and sustainable strategy for converting environmentally hazardous NO_(3)^(-)into value-added ammonia(NH3),thereby addressing both pollution mitigation and nitrogen resource recovery.However,its practical implementation remains hindered by the limited availability of electrocatalysts that simultaneously offer high activity,selectivity,and stability.In this study,we systematically investigate the catalytic potential of 300 Cu-based heteronuclear trimetallic dual-atom alloys(DAAs),featuring heterometallic dual-atom active sites embedded on a catalytically suboptimal Cu(111)surface.By combining high-throughput firstprinciples calculations with a hierarchical four-step screening strategy,we efficiently identify promising DAA catalysts for eNO_(3)RR.Among them,CrRh and MnRh catalysts stand out,exhibiting ultralow limiting potentials of-0.16 and-0.25 V,respectively,along with excellent selectivity and stability.Constantpotential simulations further reveal that both catalysts maintain high activity and selectivity across varying pH conditions and applied potentials.Geometric and electronic structure analyses indicate that the incorporation of dual-atom sites induces local lattice distortion and charge polarization,effectively tuning the electronic structure of the active centers.Notably,strong d-d orbital interactions between the embedded metal dimers give rise to new molecule-like electronic states near the Fermi level.These states facilitate effective activation of NO_(3)^(-)and NO via an electron“acceptance-donation”mechanism,driven by p-d orbital interactions between adsorbates and metal dimers.This work not only strategically designs efficient heteronuclear Cu-based DAA catalysts but also provides valuable insights into the electronic synergistic effects of dual-atom sites in modulating eNO_(3)RR performance.It establishes a promising platform for demonstrating the feasibility of constructing dual-atom active centers on pure metal surfaces for eNO_(3)RR,while broadening the potential applications of DAAs in electrocatalysis and related fields.展开更多
Developing efficient electrocatalysts for the nitrate reduction reaction(NIRR)to ammonia is vital for environmental remediation and sustainable ammonia synthesis.Metal-oxide-based single-atom catalysts(SACs)offer atom...Developing efficient electrocatalysts for the nitrate reduction reaction(NIRR)to ammonia is vital for environmental remediation and sustainable ammonia synthesis.Metal-oxide-based single-atom catalysts(SACs)offer atomic-scale efficiency,yet unclear anchoring strategies for single metal sites hinder their rational design.This study systematically explored the effects of surface-loading and latticedoping strategies on anchoring transition,rare-earth,and main-group metal atoms onto Co_(3)O_(4)via the synergy of machine learning and density functional theory calculations.Through a comprehensive assessment of stability,catalytic activity,and electronic structures,it is discovered that lattice-doping enhances SACs stability by firmly anchoring metal atoms on Co sites,while surface-loading significantly boosts catalytic activity for the NIRR.Calculations predicted that Al,Ir,Rh,and Mo sites anchored through the surface-loading strategy exhibited exceptional NIRR activity(the limiting potential for Al site can reaches-0.25 V versus the reversible hydrogen electrode),far surpassing many other configurations.To further decipher the underlying mechanisms,the machine learning algorithms,especially the treebased pipeline optimization tool model,revealed that SACs activity is highly correlated with the local environment of the active center,particularly its electronic and structural characteristics.This work establishes a new design paradigm for SACs,providing both theoretical guidelines for anchoring strategy selection and a predictive framework for efficient NIRR electrocatalysts.展开更多
A novel Cu-t-ZrO_(2)catalyst with enhanced electronic metal-support interaction(EMSI)is designed for efficient electrocatalytic conversion of nitrate(NO_(3^(-)))to ammonia(NH_(3)),achieving a remarkable Faradaic effic...A novel Cu-t-ZrO_(2)catalyst with enhanced electronic metal-support interaction(EMSI)is designed for efficient electrocatalytic conversion of nitrate(NO_(3^(-)))to ammonia(NH_(3)),achieving a remarkable Faradaic efficiency and yield rate of 97.54%and 33.64 mg h^(-1)mg_(cat)^(-1),respectively.Electrons are more likely to be transferred from Cu to t-ZrO_(2)at the electron-rich interface due to the lower work function,which promotes the formation of highly active Cu species and facilitates NO_(3^(-))adsorption,ensuring selective conversion into NH_(3).展开更多
Nitrate pollution poses a significant environmental challenge,and photocatalytic nitrate reduction has garnered considerable attention due to its efficiency and environmental advantages.Among these,the development of ...Nitrate pollution poses a significant environmental challenge,and photocatalytic nitrate reduction has garnered considerable attention due to its efficiency and environmental advantages.Among these,the development of Schottky junctions shows considerable potential for practical applications.However,the impact of metal nanoparticle size within Schottky junctions on photocatalytic nitrate reduction remains largely unexplored.In this study,we propose a novel method to modulate metal nanoparticle size within Schottky junctions by controlling light intensity during the photodeposition process.Smaller Au nanoparticles were found to enhance electron accumulation at active sites by promoting charge transfer from COF to Au,thereby improving internal electron transport.Additionally,the Schottky barrier effectively suppressed reverse electron transfer while enhancing NO_(3)^(–)adsorption and activation.The Au_(2-)COF exhibited remarkable nitrate reduction performance,achieving an ammonia yield of 382.48μmol g^(–1)h^(–1),5.7 times higher than that of pure COF.This work provides novel theoretical and practical insights into using controlled light intensity to regulate metal nanoparticle size within Schottky junctions,thereby enhancing photocatalytic nitrate reduction.展开更多
Nitrate-to-ammonia conversion presents an effective method to remediate nitrate pollution while transforming waste into a valuable product and has recently garnered significant attention.Beyond the extensively studied...Nitrate-to-ammonia conversion presents an effective method to remediate nitrate pollution while transforming waste into a valuable product and has recently garnered significant attention.Beyond the extensively studied Cu-based catalysts,Co has also garnered significant attention.Identifying the real active sites and elucidating the mechanisms are urgently needed for its development in nitrate reduction.Co_(3)O_(4),particularly its Co^(3+)sites,is an established active phase for nitrate reduction and has been extensively studied.However,unlike the deliberate construction of the Co_(3)O_(4)phase or introducing doping to expose more Co^(3+)in the previous studies,it was found in this work that the active species above could be generated in Ni-Co double hydroxides in the context of nitrate reduction.The in situ generated Co_(3)O_(4),especially the spontaneously more exposed octahedrally coordinated Co^(3+),can significantly facilitate the crucial adsorption of Nand thus the following reaction.Furthermore,incorporated Ni sites accelerate nitrate reduction kinetics by promoting hydrogenation,facilitated by their H^(*)-generating capability.This enhanced catalytic activity yields a superior NH_(3)production rate of 7.05 mmol h^(-1)cm^(-2).Besides,a new and more efficient approach for nitrate remediation that focuses on the nitrate sources was proposed and verified through experimentation.展开更多
Utilizing nitrate(NO_(3)^(-))as the nitrogen source to produce ammonia can effectively remove NO_(3)^(-)pollutant while obtaining valuable ammonia,and the understanding of the mechanisms is essential for the design of...Utilizing nitrate(NO_(3)^(-))as the nitrogen source to produce ammonia can effectively remove NO_(3)^(-)pollutant while obtaining valuable ammonia,and the understanding of the mechanisms is essential for the design of new catalysts.In this work,by using density functional theory calculations,the electroreduction mechanisms of nitrate reduction reaction(NO_(3)RR)on transition metal single atom supported on 3N-coordinated N-doped graphene(TM/N_(3)-G)are systematically investigated.It is found that the protonation of ^(*)OH acts as the potential determing steps except for the traditionally considered ^(*)NO_(3)/^(*)NO/^(*)NO_(2) protonation step and the desorption of water may play an important role for NO_(3)RR on some TM/N_(3)-G.By considering the stability of single-atom catalyst(SAC),the preferential adsorption of NO_(3)^(-)larger than H and H_(2)O,the limiting potential of whole NO_(3)RR,the selectivity toward NH3,V(Mn,Os)/pyrrolic-N_(3)-G and Mn(Ru,Ir)/pyridinic-N_(3)-G are screened out as potential SACs for NO_(3)RR.This work provides an understanding of the NO_(3)RR mechanism and highlights several promising NO_(3)RR catalysts based on the TM/N_(3)-G system.展开更多
Electrochemical nitrate(NO_(3)^(-))reduction reaction(eNO_(3)RR)to ammonia(NH3)provides a promising route for both water conservation and green ammonia synthesis.Although various catalysts were designed for the eNO_(3...Electrochemical nitrate(NO_(3)^(-))reduction reaction(eNO_(3)RR)to ammonia(NH3)provides a promising route for both water conservation and green ammonia synthesis.Although various catalysts were designed for the eNO_(3)RR and great achievements have been achieved,it is still a challenge to realize selective eNO_(3)RR to NH3at low concentration for the competing hydrogen evolution reaction(HER)and poor mass transfer of NO_(3)^(-).Herein,we designed a tandem catalyst of Pd nanoparticle loaded Cu_(2)O hierarchical nanofiber(Pd-Cu_(2)O)to improve eNO_(3)RR performance at low nitrate concentration.The Pd-Cu_(2)O shows a faraday efficiency(FE)of 95.80%and an ammonia selectivity of 97.34%at a comparatively low applied potential of-0.15 V versus RHE with low concentration.Besides,it exhibits excellent nitrate removal effects,the residual concentration of nitrate-N was only 7.22 ppm at-0.15 V.Electrochemical characterizations indicate that the abundant secondary heterojunction structures and the tandem effects of Pd-Cu_(2)O synergistic ally accelerate the transfer and conversion of NO_(3)^(-)and improve the dynamic of eNO_(3)RR at low concentration.Furthermore,the operando electrochemical impedance spectroscopy(EIS)and density functional theory(DFT)calculations suggested the tandem effects of Pd-Cu_(2)O improved the adsorption of NO_(3)^(-)and*H and thus promoted the dynamics of eNO_(3)RR at low concentration.The findings highlight the tandem effects of Pd-Cu_(2)O and provide an effective strategy for designing electrocatalysts that can be applied to low concentration and low applied potential conditions.展开更多
Cu-based electrocatalysts derived from copper oxide exhibit good electrocatalytic activity and selectivity in the electrocatalytic nitrate reduction reaction(NO_(3)RR).However,the origin of the enhanced selectivity an...Cu-based electrocatalysts derived from copper oxide exhibit good electrocatalytic activity and selectivity in the electrocatalytic nitrate reduction reaction(NO_(3)RR).However,the origin of the enhanced selectivity and activity of NO_(3)RR is unclear.Herein,we investigate the activity of three copper oxide/hydroxidederived catalysts,and verify the phase changes during the reduction process through electrochemical in situ Raman spectroscopy.Our results show that all phases ultimately transform into metallic copper during the electrochemical synthesis process,supporting that the zero valent copper phase is the actual active phase.The high-density grain boundaries and defects are responsible for the activity of NO_(3)RR.By combining with the nickel oxide,the selectivity of the catalyst for NO_(3)RR can be further improved,achieving an ammonia Faradaic efficiency of~96% and an ammonia yield of 3.2 mmol cm^(-2)h^(-1)at -0.05 V_(RHE).This experimental design of oxygen intercalation/elimination brings a more flexible electrode,which provides a new methodology for constructing the grain boundary toward NO_(3)RR.展开更多
基金supported by the Natural Science Foundation(NSF)of China(Nos.22205015,22175020,and 22235001)the National Postdoctoral Program for Innovative Talents(No.BX20220032)+2 种基金the China Postdoctoral Science Foundation Funded Project(No.2022BG013)the Fundamental Research Funds for the Central Universities(Nos.00007709,00007770,and FRFBR-23-02B)University of Science and Technology Beijing is gratefully acknowledged.
文摘In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry between corresponding building blocks and linking units in addition to the unmanageable packing of 1D organic chains once formed.Herein,two novel imide-linked 1D COFs with phthalocyanine building blocks,namely NiPc-CZDM-COF and NiPc-CZDL-COF,were fabricated from the hydrothermal synthesis reaction of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato nickel(II)(NiPc(COOH)_(8))with 9H-carbazole-3,6-diamine(CZDM)and 4,4′-(9H-carbazole-3,6-diyl)dianiline(CZDL),respectively.Two COFs have high crystallinity on the basis of powder X-ray diffraction analysis and high-resolution transmission electron microscopy.Due to their high ratio of exposed active centers on the edge sites of porous ribbons,both NiPc-CZDM-COF and NiPc-CZDL-COF electrodes display high utilization efficiency of NiPc electroactive sites of 8.0%and 7.5% according to the electrochemical measurement,resulting in their excellent capacity toward electrocatalytic nitrate reduction with the nitrate-to-NH3 Faradaic efficiency of nearly 100%.In particular,NiPc-CZDM-COF electrode exhibits superior electrocatalytic performance with high NH3 partial current density of−246 mA/cm^(2),ammonia yield rate of 19.5 mg cm^(−2) h^(−1),and turnover frequency of 5.8 s^(−1) at−1.2 V in an H-type cell associated with its higher conductivity.This work reveals the good potential of 1D porous crystalline materials in electrocatalysis.
基金supported by the National Key Research and Development Program of China(2023YFE0120900)the National Natural Science Foundation of China(52377160)+2 种基金the National Natural Science Foundation of China National Young Talents Project(GYKP010)Shaanxi Provincial Natural Science Program(2023-JCYB-425)Xi’an Jiaotong University Young Top Talents Program。
文摘Ammonia is the cornerstone of modern agriculture,providing a critical nitrogen source for global food production and serving as a key raw material for numerous industrial chemicals.Electrocatalytic nitrate reduction,as an environmentally friendly method for synthesizing ammonia,not only mitigates the reliance on current ammonia synthesis processes fed by traditional fossil fuels but also effectively reduces nitrate pollution resulting from agricultural and industrial activities.This review explores the fundamental principles of electrocata lytic nitrate reduction,focusing on the key steps of electron transfer and ammonia formation.Additionally,it summarizes the critical factors influencing the performance and selectivity of the reaction,including the properties of the electrolyte,operating voltage,electrode materials,and design of the electrolytic cell.Further discussion of recent advances in electrocatalysts,including pure metal catalysts,metal oxide catalysts,non-metallic catalysts,and composite catalysts,highlights their significant roles in enhancing both the efficiency and selectivity of electrocata lytic nitrate to ammonia(NRA)reactions.Critical challenges for the industrial NRA trials and further outlooks are outlined to propel this strategy toward real-world applications.Overall,the review provides an in-depth overview and comprehensive understanding of electrocata lytic NRA technology,thereby promoting further advancements and innovations in this domain.
基金National Natural Science Foundation of China (52371228, 52402045)fund of Key Laboratory of Advanced Materials of Ministry of Education(Advmat-2414)。
文摘Electrocatalytic nitrate reduction reaction (NO_(3)-RR) to ammonia under ambient conditions is expected to be a green process for ammonia synthesis and alleviate water pollution issues.We report a CuO nanoparticles incorporated on nitrogen-doped porous carbon (CuO@NC) catalyst for NO_(3)-RR.Part of Cu(Ⅱ) is reduced to Cu(Ⅰ) during the NO_(3)-RR process to construct Cu(Ⅰ)-Cu(Ⅱ) pairs,confirmed by in situ X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.Density functional theory (DFT) calculations indicated that the formation of Cu(Ⅰ) could provide a reaction path with smaller energy barrier for NO_(3)-RR,while Cu(Ⅱ) effectively suppressed the competition of hydrogen evolution reaction (HER).As a result,CuO@NC catalyst achieved a Faradaic efficiency of 84.2% at -0.49 V versus reversible hydrogen electrode (RHE),and a NH_(3)yield rate of 17.2 mg h^(-1)mg^(-1)cat.at -0.79 V vs.RHE,higher than the HaberBosch process (<3.4 g h^(-1)g^(-1)cat.).This work may open a new avenue for effective NO_(3)-RR by modulating oxidation states.
基金supported by the National Natural Science Foundation of China(12205300(H.S.),12405377(M.H.L))the Postdoctoral Science Foundation of China(2024M763694(M.H.L))+3 种基金the Natural Science Foundation of Hunan Province(2024JJ4027(H.S.))the Postdoctoral Fellowship Program of CPSF under Grant Number GZB20240859(M.H.L)financial support from the Hunan Normal University Program(grant05311204666)financial support from the 2024 Large Instrument Testing Open Fund of Hunan Normal University(24CSY033,24CSY086)。
文摘The electrochemical conversion of nitrate,a widespread water pollutant,into valuable ammonia represents a green and decentralized approach to ammonia synthesis.However,the sluggish multielectronproton coupling path and the low reactive species(nitrate and proton)concentration at the catalyst interface inhibit the efficiency of ammonia production from nitrate reduction reaction(NitRR).Herein,we introduce a novel iron-based tandem catalyst encapsulated by reduced graphene oxide(denoted as Fe-rGO),with a superior ammonia production rate of 47.815 mg h^(-1)mg_(ca)^(t-1)and a high Faraday efficiency(FE)of 96.51%at an applied potential of-0.5 V.It also delivers a robust stability with FE above90%under a current density of 250 mA cm^(-2)for 50 h.In situ X-ray absorption spectroscopy reveals that the FeO_(x)is dynamically translated to Fe~0 site concurrently with the enhancement of the NH_(3)production rate,suggesting the Fe^(0) site as hydrogenation active center.The asymmetric distribution of surface charges of rGO not only enriches nitrate ions at the catalytic interface and promotes the hydrogenation process in NitRR,but also protects the iron species and ensures their stability during electrolysis.The Zn-NO_(3)^(-)battery demonstrates an impressive FE of 88.6%,highlighting its exceptional potential for practical applications.
基金financially supported by the Shanghai Science and Technology Plan Project(No.23ZR1467000)Basic Research Project of Tongji University(No.22120240354)+2 种基金State Key Laboratory of Treatments and Recycling for Organic Effluents by Adsorption in Petroleum,Chemical Industry(No.SDHY2206)National Natural Science Foundation of China(No.21976134)the Fundamental Research Funds for the Central Universities。
文摘Electrocatalytic reduction of nitrate to ammonia offers an environmentally friendly and sustainable approach for ammonia production,but it involves a multi-step reaction process with complex intermediates,and still faces the challenge of high activity and high selectivity.Herein,a high-entropy nanoalloy was synthesized via high-temperature annealing of metal salt with dopamine as a carbon source for electrocatalytic reduction of nitrate to ammonia.The FeCoNiCuRu_(1.5)/C catalyst displays a conversion rate of 90.2%and an ammonia selectivity of 92.2% at-0.74 V(vs.RHE),significantly surpassing the performance of lowentropy alloys such as FeCo/C by 1.5–2 times.Moreover,FeCoNiCuRu_(1.5)/C maintains a consistent nitrate conversion rate of about 90.0% after 120 h of continuous operation(10 cycles),indicating high stability.The superior performance of FeCoNiCuRu_(1.5)/C can be attributed to the synergetic relay catalysis among Fe,Co,Ni,Cu,and Ru sites.This synergy enhances nitrate adsorption due to the optimized electronic structure of multiple active sites,which facilitates the nitrate reduction to intermediates.Subsequently,the effective active hydrogen produced at the Ru site,in conjunction with adjustments at other metal sites,promotes the selective transformation of the intermediates into ammonia.This work not only highlights the efficacy of synergetic relay electrocatalysis but also opens new avenues for developing highly efficient multi-site catalysts.
基金supported by grants from the National Natural Science Foundation of China (22178339)2023 Innovation-driven Development Special Foundation of Guangxi(AA23023021)the Hundred Talents Program (A) of the Chinese Academy of Sciences
文摘Red mud(RM)is a solid waste generated in the aluminum industry after the extraction of alumina oxide;its multiple elements and higher pH value likely pose a severe threat to the environment after treatment.However,RM's higher concentrations of metal components,particularly Fe_(2)O_(3)and rare earth elements(REEs),render RM promising for catalytic application.Hence,this work showed an efficient high-speed RM to catalyze electrocatalytic nitrate-to-ammonia reduction reaction(NARR).RM calcined at 500℃(RM-500)exhibited excellent catalytic performance.Faradaic efficiency of ammonia(FENH_(3))in an electrolyte solution containing 1 mol·L^(-1)NO_(3)-achieved a maximum value of 92.3%at-0.8 V(vs.RHE).Additionally,24-h cycle testing and post-reaction PXRD and SEM indicated that the RM-500 electrocatalyst is stable during NARR.The RM-500 demonstrated a high FE of NH_(3)-to-NO_(3)-of 89.7%at 1.85 V(vs.RHE),showing great potential in the ammonia fuel cells technology and achieving the nitrogen cycle.
基金supported in part by National Natural Science Foundation of China(No.51925102)National Key R&D Program of China(No.2022YFA1504101)。
文摘In this work,an effective catalyst of Cu/MnOOH has been successfully constructed for electrochemical nitrate reduction reaction(e NO_(3)RR)for synthesis of ammonia(NH_(3))under ambient conditions.The substrate of MnOOH plays an important role on the size and electronic structure of Cu nanoparticles,where Cu has the ultrafine size of 2.2 nm and positive shift of its valence states,which in turn causes the increased number of Cu active sites and enhanced intrinsic activity of every active site.As a result,this catalyst realizes an excellent catalytic performance on eNO_(3)RR with the maximal NH_(3)Faraday efficiency(FE)(96.8%)and the highest yield rate(55.51 mg h^(-1)cm^(-2))at a large NH_(3)partial current density of700 m A/cm^(2),which could help to promote the industrialization of NH_(3)production under ambient conditions.
基金supported by Shanghai Science and Technology Plan Project(No.23ZR1467000)the Fundamental Research Funds for the Central University(No.22120240354)+1 种基金the National Natural Science Foundation of China(No.22131004)the Leading Scientific Research Project from China National Nuclear Corporation(No.CNNC–CXLM-202205).
文摘The efficient electrocatalytic nitrate(NO_(3)^(−))reduction to ammonia(NRA)offers a sustainable alternative for both environmental remediation and ammonia synthesis.Developing advanced electrocatalysts with rationally designed spatial arrangement of active sites and optimizing the synergetic effect among components are crucial for high efficiency and selectivity.Herein,we present Fe/N active sites decorated on porous carbon nanofibers(CNFs)with encapsulated FeCo nanoparticles(FeCo@CNFs-Fe/N)as electrocatalysts for NRA.The FeCo@CNFs-Fe/N catalyst demonstrates exceptional performance,achieving a high ammonia yield of 498.18μmol/(h·g_(cat)).Meanwhile,the enhanced reduction activity,especially the reduction in overpotential by 0.565 V,is 3–10 times higher than that of FeCo-encapsulated and Fe/N-modified CNFs-based catalysts.The enhanced catalytic activity is attributed to the efficient structure design and optimized spatial distribution of active sites,which enhance the electron transfer rate and decrease the reaction energy barrier.Mechanistic studies reveal that the synergetic effect between encapsulated nanoparticles and surface-modified Fe/N sites plays a crucial role in promoting efficient nitrate adsorption and selective ammonia production.These findings highlight the potential of strategically engineered CNF-based composites for nitrate reduction and other advanced electrocatalytic applications.
基金Project supported by the National Natural Science Foundation of China(21971129,21961022,21661023)the Inner Mongolia Autonomous Region 2022 Leading Talent Team of Science and Technology(2022LJRC0008)+5 种基金the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2022MS02014,2021BS02007)the Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region(NJYT23031)the 111 Project(D20033)the"Grassland Leading Talent"Program of Inner Mongoliathe"Grassland-Talent"Innovation Team of Inner Mongoliathe"Science and Technology for A Better Development of Inner Mongolia"Program(2020XM03)。
文摘The excess emission of nitrate from human activities disturbs the global nitrogen cycle and thus needs to be remediated.In this work,we prepared a La-doped Co_(3)O_(4)nanoneedle arrays catalyst for highly efficient electrocatalytic reduction of NO_(3)^(-) to NH_(3)at low concentration.The La-doped Co_(3)O_(4)nanoneedle arrays exhibit remarkable activity with the highest Faradaic efficiency of 95.5%and an ammonia yield rate of 4.08 mg/(h·cm^(2))at-0.3 V versus RHE in 0.02 mol/L NO_(3)^(-).Experiments and theoretical calculations show that the La doping not only facilitates the surface reconstruction to form active La-Co(OH)_(2),but also inhibits the hydrogen evolution reaction over Co sites,thus promoting the NH_(3)production.This work provides new insights into the promoting effect of the rare earth elements in transition metalbased electrocatalyst for nitrate reduction.
基金support from the National Natural Science Foundation of China(Nos.52370100,52000146,and 51978098)China Postdoctoral Science Foundation(No.2020M673351).
文摘Catalytic reduction of nitrate over bimetallic catalysts has emerged as a technology for sustainable treatment of nitrate-containing groundwater.However,the structure of bimetallic has been much less investigated for catalyst optimization.Herein,two main types of Pd-Cu bimetallic nanocrystal structures,heterostructure and intermetallic,were prepared and characterized using high-resolution transmission electron microscopy(HRTEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The results show that two individual Pd and Cu nanocrystals with a mixed interface exist in the heterostructure nanocrystals,while Pd and Cu atoms are uniformly distributed across the intermetallic Pd-Cu nanocrystals.The catalytic nitrate reduction experiments were carried out in a semibatch reactor under constant hydrogen flow.The nitrate conversion rate of the heterostructure Pd-Cu nanocrystals supported onα-Al_(2)O_(3),γ-Al_(2)O_(3),SBA-15,and XC-72R exhibited 3.82-,6.76-,4.28-,2.44-fold enhancements relative to the intermetallic nanocrystals,and the nitrogen and nitrite were the main products for the heterostructure and intermetallic Pd-Cu nanocrystals,respectively.This indicates that the catalytic nitrate reduction over Pd-Cu catalyst is sensitive to the bimetallic structures of the catalysts,and heterostructure bimetallic nanocrystals exhibit better catalytic performances on both the activity and selectivity,which may provide new insights into the design and optimization of catalysts to improve catalytic activity and selectivity for nitrate reduction in water.
基金support from the National Natural Science Foundation of China(Nos.U21A2034 and 21876052)the Guangdong Special Support Plan for Innovation Teams(No.2019BT02L218)+1 种基金the Guangdong Special Support Plan for Young Top-notch Talents(No.2019TQ05L179)the Natural Science Foundation of Guangdong Province,China(No.2021B1515120077)。
文摘Electrochemical nitrate reduction(NO_(3)RR)offers a promising avenue for treating nitrate-contaminated water and recovering ammonia(NH_(3)),yet the complexities of direct electron transfer(DET)and hydrogen atom transfer(HAT)mechanisms crucial for efficiency remain elusive.This study bridges the gap with a combined experimental and theoretical approach,elucidating the impact of catalyst structure on NO3RR pathways.We discover that catalysts favoring strong NO_(3^(-))adsorption and efficient water dissociation were more inclined towards DET,enhancing denitrification.The Fe@Fe_(3)O_(4)/FF cathode,leveraging the synergistic interplay between metallic Fe and Fe_(3)O_(4),excelled in NO3RR via DET,achieving an NH3yield of 0.28 mmol h-1cm-2and a Faradaic efficiency of 95.7%for NH3at-1.6 V(vs.SCE),with minimal nitrite accumulation at 100 mmol/L nitrate.Conversely,the Fe/FF and Fe_(3)O_(4)/CC cathodes showed reduced NH3production and increased nitrite levels,attributed to the lack of Fe_(3)O_(4)and metallic Fe,respectively,resulting in a dominant HAT mechanism.Moreover,Fe@Fe_(3)O_(4)/FF facilitated complete denitrification in real wastewater treatment by harnessing Cl^(-)for electrochemically mediated breakpoint chlorination.This research not only deepens our understanding of NO3RR mechanisms but also paves the way for designing superior nitrate reduction catalysts.
基金financially supported by the National Natural Science Foundation of China(22179035)the Science Fund for Distinguished Young Scholars of Heilongjiang Province(JQ2022B001)the Fundamental Research Funds for the Universities of Heilongjiang Province of China(2023-KYYWF1440)。
文摘Electrocatalytic nitrate reduction reaction(NitRR)utilizing water as a hydrogen source under ambient conditions represents a highly promising avenue for sustainable ammonia synthesis and environmental remediation.However,achieving high efficiency and selectivity in NitRR is fundamentally challenged by the complex lifecycle management of active hydrogen derived from water splitting.This review provides a timely and comprehensive analysis centered on the pivotal role and meticulous regulation of active hydrogen throughout the NitRR process.We first elucidate the distinct functions and characteristics of various hydrogen species,followed by a survey of advanced characterization techniques crucial for monitoring the dynamics of active hydrogen.Critically,three core strategies were systematically dissected to modulate the active hydrogen lifecycle:accelerating water activation and dissociation,enhancing the directional transport of hydrogen species,and precisely tuning active hydrogen coupling pathways while suppressing parasitic hydrogen evolution.By consolidating current understanding from both catalyst design and reaction mechanism perspectives,this review offers a hydrogen-centric roadmap and highlights emerging opportunities for rationally engineering advanced NitRR systems.
基金supported by the Water Conservancy Science and Technology Project of Jiangsu Province,China(No.2024005,2025012)。
文摘Electrochemical nitrate(NO_(3)^(-))reduction reaction(eNO_(3)RR)presents a promising and sustainable strategy for converting environmentally hazardous NO_(3)^(-)into value-added ammonia(NH3),thereby addressing both pollution mitigation and nitrogen resource recovery.However,its practical implementation remains hindered by the limited availability of electrocatalysts that simultaneously offer high activity,selectivity,and stability.In this study,we systematically investigate the catalytic potential of 300 Cu-based heteronuclear trimetallic dual-atom alloys(DAAs),featuring heterometallic dual-atom active sites embedded on a catalytically suboptimal Cu(111)surface.By combining high-throughput firstprinciples calculations with a hierarchical four-step screening strategy,we efficiently identify promising DAA catalysts for eNO_(3)RR.Among them,CrRh and MnRh catalysts stand out,exhibiting ultralow limiting potentials of-0.16 and-0.25 V,respectively,along with excellent selectivity and stability.Constantpotential simulations further reveal that both catalysts maintain high activity and selectivity across varying pH conditions and applied potentials.Geometric and electronic structure analyses indicate that the incorporation of dual-atom sites induces local lattice distortion and charge polarization,effectively tuning the electronic structure of the active centers.Notably,strong d-d orbital interactions between the embedded metal dimers give rise to new molecule-like electronic states near the Fermi level.These states facilitate effective activation of NO_(3)^(-)and NO via an electron“acceptance-donation”mechanism,driven by p-d orbital interactions between adsorbates and metal dimers.This work not only strategically designs efficient heteronuclear Cu-based DAA catalysts but also provides valuable insights into the electronic synergistic effects of dual-atom sites in modulating eNO_(3)RR performance.It establishes a promising platform for demonstrating the feasibility of constructing dual-atom active centers on pure metal surfaces for eNO_(3)RR,while broadening the potential applications of DAAs in electrocatalysis and related fields.
基金the Shandong Province Colleges and Universities Youth Innovation Technology Plan Innovation Team Project(2022KJ285)the National Natural Science Foundation of China(52202092)the Major Subject Project of the University of Jinan。
文摘Developing efficient electrocatalysts for the nitrate reduction reaction(NIRR)to ammonia is vital for environmental remediation and sustainable ammonia synthesis.Metal-oxide-based single-atom catalysts(SACs)offer atomic-scale efficiency,yet unclear anchoring strategies for single metal sites hinder their rational design.This study systematically explored the effects of surface-loading and latticedoping strategies on anchoring transition,rare-earth,and main-group metal atoms onto Co_(3)O_(4)via the synergy of machine learning and density functional theory calculations.Through a comprehensive assessment of stability,catalytic activity,and electronic structures,it is discovered that lattice-doping enhances SACs stability by firmly anchoring metal atoms on Co sites,while surface-loading significantly boosts catalytic activity for the NIRR.Calculations predicted that Al,Ir,Rh,and Mo sites anchored through the surface-loading strategy exhibited exceptional NIRR activity(the limiting potential for Al site can reaches-0.25 V versus the reversible hydrogen electrode),far surpassing many other configurations.To further decipher the underlying mechanisms,the machine learning algorithms,especially the treebased pipeline optimization tool model,revealed that SACs activity is highly correlated with the local environment of the active center,particularly its electronic and structural characteristics.This work establishes a new design paradigm for SACs,providing both theoretical guidelines for anchoring strategy selection and a predictive framework for efficient NIRR electrocatalysts.
基金supported by the Natural Scientific Foundation of China(Nos.22127803,22174110,22203050)Natural Scientific Foundation of Shandong(No.ZR2022QB002)China Postdoctoral Science Foundation(No.2020T130331)。
文摘A novel Cu-t-ZrO_(2)catalyst with enhanced electronic metal-support interaction(EMSI)is designed for efficient electrocatalytic conversion of nitrate(NO_(3^(-)))to ammonia(NH_(3)),achieving a remarkable Faradaic efficiency and yield rate of 97.54%and 33.64 mg h^(-1)mg_(cat)^(-1),respectively.Electrons are more likely to be transferred from Cu to t-ZrO_(2)at the electron-rich interface due to the lower work function,which promotes the formation of highly active Cu species and facilitates NO_(3^(-))adsorption,ensuring selective conversion into NH_(3).
文摘Nitrate pollution poses a significant environmental challenge,and photocatalytic nitrate reduction has garnered considerable attention due to its efficiency and environmental advantages.Among these,the development of Schottky junctions shows considerable potential for practical applications.However,the impact of metal nanoparticle size within Schottky junctions on photocatalytic nitrate reduction remains largely unexplored.In this study,we propose a novel method to modulate metal nanoparticle size within Schottky junctions by controlling light intensity during the photodeposition process.Smaller Au nanoparticles were found to enhance electron accumulation at active sites by promoting charge transfer from COF to Au,thereby improving internal electron transport.Additionally,the Schottky barrier effectively suppressed reverse electron transfer while enhancing NO_(3)^(–)adsorption and activation.The Au_(2-)COF exhibited remarkable nitrate reduction performance,achieving an ammonia yield of 382.48μmol g^(–1)h^(–1),5.7 times higher than that of pure COF.This work provides novel theoretical and practical insights into using controlled light intensity to regulate metal nanoparticle size within Schottky junctions,thereby enhancing photocatalytic nitrate reduction.
基金financially supported by the National Natural Science Foundation(No.22171212)the National Key Research and Development Program of China(No.2024YFC3908905)+1 种基金the International Exchange Grant(IEC/NSFC/201078)through the Royal Society UK and NSFCTriple boost strategy for low energy consuming catalytic ammonia synthesis(Trimonia)through UK EPSRC UK-HyRES Funding。
文摘Nitrate-to-ammonia conversion presents an effective method to remediate nitrate pollution while transforming waste into a valuable product and has recently garnered significant attention.Beyond the extensively studied Cu-based catalysts,Co has also garnered significant attention.Identifying the real active sites and elucidating the mechanisms are urgently needed for its development in nitrate reduction.Co_(3)O_(4),particularly its Co^(3+)sites,is an established active phase for nitrate reduction and has been extensively studied.However,unlike the deliberate construction of the Co_(3)O_(4)phase or introducing doping to expose more Co^(3+)in the previous studies,it was found in this work that the active species above could be generated in Ni-Co double hydroxides in the context of nitrate reduction.The in situ generated Co_(3)O_(4),especially the spontaneously more exposed octahedrally coordinated Co^(3+),can significantly facilitate the crucial adsorption of Nand thus the following reaction.Furthermore,incorporated Ni sites accelerate nitrate reduction kinetics by promoting hydrogenation,facilitated by their H^(*)-generating capability.This enhanced catalytic activity yields a superior NH_(3)production rate of 7.05 mmol h^(-1)cm^(-2).Besides,a new and more efficient approach for nitrate remediation that focuses on the nitrate sources was proposed and verified through experimentation.
基金partially supported by the National Natural Science Foundation of China(No.22373092,No.22288201)CAS Project for Young Scientists in Basic Research(YSBR-051)supported by USTC Tang Scholarship。
文摘Utilizing nitrate(NO_(3)^(-))as the nitrogen source to produce ammonia can effectively remove NO_(3)^(-)pollutant while obtaining valuable ammonia,and the understanding of the mechanisms is essential for the design of new catalysts.In this work,by using density functional theory calculations,the electroreduction mechanisms of nitrate reduction reaction(NO_(3)RR)on transition metal single atom supported on 3N-coordinated N-doped graphene(TM/N_(3)-G)are systematically investigated.It is found that the protonation of ^(*)OH acts as the potential determing steps except for the traditionally considered ^(*)NO_(3)/^(*)NO/^(*)NO_(2) protonation step and the desorption of water may play an important role for NO_(3)RR on some TM/N_(3)-G.By considering the stability of single-atom catalyst(SAC),the preferential adsorption of NO_(3)^(-)larger than H and H_(2)O,the limiting potential of whole NO_(3)RR,the selectivity toward NH3,V(Mn,Os)/pyrrolic-N_(3)-G and Mn(Ru,Ir)/pyridinic-N_(3)-G are screened out as potential SACs for NO_(3)RR.This work provides an understanding of the NO_(3)RR mechanism and highlights several promising NO_(3)RR catalysts based on the TM/N_(3)-G system.
基金financially supported by the National Key Research and Development Program of China(No.2021YFB4000604)National Natural Science Foundation of China(No.52271220)+2 种基金The Program of the Ministry of Education of China for Introducing Talents of Discipline to Universities(No.B12015)the Fundamental Research Funds for the Central UniversitiesHaihe Laboratory of Sustainable Chemical Transformations,Guangxi Collaborative Innovation Centre of Structure and Property for New Energy and Materials,Science Research and Technology Development Project of Guilin(No.20210102-4)
文摘Electrochemical nitrate(NO_(3)^(-))reduction reaction(eNO_(3)RR)to ammonia(NH3)provides a promising route for both water conservation and green ammonia synthesis.Although various catalysts were designed for the eNO_(3)RR and great achievements have been achieved,it is still a challenge to realize selective eNO_(3)RR to NH3at low concentration for the competing hydrogen evolution reaction(HER)and poor mass transfer of NO_(3)^(-).Herein,we designed a tandem catalyst of Pd nanoparticle loaded Cu_(2)O hierarchical nanofiber(Pd-Cu_(2)O)to improve eNO_(3)RR performance at low nitrate concentration.The Pd-Cu_(2)O shows a faraday efficiency(FE)of 95.80%and an ammonia selectivity of 97.34%at a comparatively low applied potential of-0.15 V versus RHE with low concentration.Besides,it exhibits excellent nitrate removal effects,the residual concentration of nitrate-N was only 7.22 ppm at-0.15 V.Electrochemical characterizations indicate that the abundant secondary heterojunction structures and the tandem effects of Pd-Cu_(2)O synergistic ally accelerate the transfer and conversion of NO_(3)^(-)and improve the dynamic of eNO_(3)RR at low concentration.Furthermore,the operando electrochemical impedance spectroscopy(EIS)and density functional theory(DFT)calculations suggested the tandem effects of Pd-Cu_(2)O improved the adsorption of NO_(3)^(-)and*H and thus promoted the dynamics of eNO_(3)RR at low concentration.The findings highlight the tandem effects of Pd-Cu_(2)O and provide an effective strategy for designing electrocatalysts that can be applied to low concentration and low applied potential conditions.
基金supported by the National Science and Technology Major Project(2022YFA1205200)the National Natural Science Foundation of China(22269016,22479083,22405138)the Group Project of Developing Inner Mongolia through Talents from the Talents Work Leading Group under the CPC Inner Mongolia Autonomous Regional Committee(2025TYL03)。
文摘Cu-based electrocatalysts derived from copper oxide exhibit good electrocatalytic activity and selectivity in the electrocatalytic nitrate reduction reaction(NO_(3)RR).However,the origin of the enhanced selectivity and activity of NO_(3)RR is unclear.Herein,we investigate the activity of three copper oxide/hydroxidederived catalysts,and verify the phase changes during the reduction process through electrochemical in situ Raman spectroscopy.Our results show that all phases ultimately transform into metallic copper during the electrochemical synthesis process,supporting that the zero valent copper phase is the actual active phase.The high-density grain boundaries and defects are responsible for the activity of NO_(3)RR.By combining with the nickel oxide,the selectivity of the catalyst for NO_(3)RR can be further improved,achieving an ammonia Faradaic efficiency of~96% and an ammonia yield of 3.2 mmol cm^(-2)h^(-1)at -0.05 V_(RHE).This experimental design of oxygen intercalation/elimination brings a more flexible electrode,which provides a new methodology for constructing the grain boundary toward NO_(3)RR.
