The self-reforming of coke oven gas(COG)in a gas-based shaft furnace was investigated,employing metallized iron as a catalyst.Thermodynamic analyses,supported by FactSage 8.3 calculations and regression modeling,were ...The self-reforming of coke oven gas(COG)in a gas-based shaft furnace was investigated,employing metallized iron as a catalyst.Thermodynamic analyses,supported by FactSage 8.3 calculations and regression modeling,were used to investigate the effects of temperature(700–1100℃),CO_(2)(3%–10%),and H_(2)O(1%–9%)concentrations on CH_(4) conversion efficiency.Results indicate that CH_(4) conversion exceeds 90%at temperatures above 1000℃,with CO_(2) and H_(2)O concentrations at 9%and 5%,respectively.During the reforming process,introducing CO_(2) provides additional oxygen,facilitating the oxidation of CH_(4),while H_(2)O enhances H_(2) production through the steam reforming pathway.Experimental findings reveal a CH_(4) conversion of 85.83%with a H_(2)/CO ratio of 5.44 at 1050℃.In addition,an optimal H_(2)O concentration of 6%yields the highest CH_(4) conversion of 84.24%,while CO_(2) exhibits minimal effects on promoting the reforming process.Increasing the metallization rate of pellets from 43%to 92%significantly enhances CH_(4) reforming.This is mainly due to the fact that metallized iron is vital in promoting CH_(4) dissociation and improving syngas yield by providing active sites for the redox cycle of CO_(2) and H_(2)O.展开更多
Low-concentration coal mine methane(LC-CMM),which is predominantly composed of methane,serves as a clean and low-carbon energy resource with significant potential for utilization.Utilizing LC-CMM as fuel for solid oxi...Low-concentration coal mine methane(LC-CMM),which is predominantly composed of methane,serves as a clean and low-carbon energy resource with significant potential for utilization.Utilizing LC-CMM as fuel for solid oxide fuel cells(SOFCs)represents an efficient and promising strategy for its effective utilization.However,direct application in Ni-based anodes induces carbon deposition,which severely degrades cell performance.Herein,a medium-entropy oxide Sr_(2)FeNi_(0.1)Cr_(0.3)Mn_(0.3)Mo_(0.3)O_(6−δ)(SFNCMM)was developed as an anode internal reforming catalyst.Following reduction treatment,FeNi_(3) nano-alloy particles precipitate on the surface of the material,thereby significantly enhancing its catalytic activity for LC-CMM reforming process.The catalyst achieved a methane conversion rate of 53.3%,demonstrating excellent catalytic performance.Electrochemical evaluations revealed that SFNCMM-Gd_(0.1)Ce_(0.9)O_(2−δ)(GDC)with a weight ratio of 7:3 exhibited superior electrochemical performance when employed as the anodic catalytic layer.With H_(2) and LC-CMM as fuels,the single cell achieved maximum power densities of 1467.32 and 1116.97 mW·cm^(−2) at 800℃,respectively,with corresponding polarization impedances of 0.17 and 1.35Ω·cm^(2).Furthermore,the single cell maintained stable operation for over 100 h under LC-CMM fueling without significant carbon deposition,confirming its robust resistance to carbon formation.These results underscore the potential of medium-entropy oxides as highly effective catalytic layers for mitigating carbon deposition in SOFCs.展开更多
The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methaner...The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methanereforming(SMR)and ship-based carbon capture(SBCC).The first refers to the common practice used to obtainhydrogen from methane(often derived from natural gas),where steam reacts with methane to produce hydrogenand carbon dioxide(CO_(2)).The second refers to capturing the CO_(2) generated during the SMR process on boardships.By capturing and storing the carbon emissions,the process significantly reduces its environmental impact,making the hydrogen production“blue,”as opposed to“grey”(which involves CO_(2) emissions without capture).For the SMR process,the analysis reveals that increasing the reformer temperature enhances both the processperformance and CO_(2) emissions.Conversely,a higher steam-to-carbon(s/c)ratio reduces hydrogen yield,therebydecreasing thermal efficiency.The study also shows that preheating the air and boil-off gas(BOG)before theyenter the combustion chamber boosts overall efficiency and curtails CO_(2) emissions.In the SBCC process,puremonoethanolamine(MEA)is employed to capture the CO_(2) generated by the exhaust gases from the SMR process.The results indicate that with a 90%CO_(2) capture rate,the associated heat consumption amounts to 4.6 MJ perkilogram of CO_(2) captured.This combined approach offers a viable pathway to produce blue hydrogen on LNGcarriers while significantly reducing the carbon footprint.展开更多
CeO_(2) based semiconductor are widely used in solar-driven photothermal catalytic dry reforming of methane(DRM)reaction,but still suffer from low activity and low light utilization efficiency.This study developed gra...CeO_(2) based semiconductor are widely used in solar-driven photothermal catalytic dry reforming of methane(DRM)reaction,but still suffer from low activity and low light utilization efficiency.This study developed graphite-CeO_(2) interfaces to enhance solar-driven photothermal catalytic DRM.Compared with carbon nanotubes-modified CeO_(2)(CeO_(2)-CNT),graphite-modified CeO_(2)(CeO_(2)-GRA)constructed graphite-CeO_(2) interfaces with distortion in CeO_(2),leading to the formation abundant oxygen vacancies.These graphite-CeO_(2) interfaces with oxygen vacancies enhanced optical absorption and promoted the generation and separation of photogenerated carriers.The high endothermic capacity of graphite elevated the catalyst surface temperature from 592.1−691.3℃,boosting light-to-thermal conversion.The synergy between photogenerated carriers and localized heat enabled Ni/CeO_(2)-GRA to achieve a CO production rate of 9985.6 mmol/(g·h)(vs 7192.4 mmol/(g·h)for Ni/CeO_(2))and a light-to-fuel efficiency of 21.8%(vs 13.8%for Ni/CeO_(2)).This work provides insights for designing graphite-semiconductor interfaces to advance photothermal catalytic efficiency.展开更多
With ongoing global warming and increasing energy demands,the CH_(4)-CO_(2)reforming reaction(dry reforming of methane,DRM)has garnered significant attention as a promising carbon capture and utilization technology.Ni...With ongoing global warming and increasing energy demands,the CH_(4)-CO_(2)reforming reaction(dry reforming of methane,DRM)has garnered significant attention as a promising carbon capture and utilization technology.Nickel-based catalysts are renowned for their outstanding activity and selectivity in this process.The impact of metal-support interaction(MSI),on Ni-based catalyst performance has been extensively researched and debated recently.This paper reviews the recent research progress of MSI on Ni-based catalysts and their characterization and modulation strategies in catalytic reactions.From the perspective of MSI,the effects of different carriers(metal oxides,carbon materials and molecular sieves,etc.)are introduced on the dispersion and surface structure of Ni active metal particles,and the effect of MSI on the activity and stability of DRM reactions on Ni-based catalysts is discussed in detail.Future research should focus on better understanding and controlling MSI to improve the performance and durability of nickel-based catalysts in CH_(4)-CO_(2)reforming,advancing cleaner energy technologies.展开更多
High density polyethylene(HDPE)pyrolysis and in-line oxidative steam reforming was carried out in a two-step reaction system consisting of a conical spouted bed reactor and a fluidized bed reactor.Continuous plastic p...High density polyethylene(HDPE)pyrolysis and in-line oxidative steam reforming was carried out in a two-step reaction system consisting of a conical spouted bed reactor and a fluidized bed reactor.Continuous plastic pyrolysis was conducted at 550℃ and the volatiles formed were fed in-line to the oxidative steam reforming step(space-time 3.12 gcat min gHDPE−1;ER=0.2 and steam/plastic=3)operating at 700℃.The influence Ni based reforming catalyst support(Al_(2)O_(3),ZrO_(2),SiO_(2))and promoter(CeO_(2),La_(2)O_(3))have on HDPE pyrolysis volatiles conversion and H_(2) production was assessed.The catalysts were prepared by the wet impregnation and they were characterized by means of N_(2) adsorption-desorption,X-ray fluorescence,temperature-programmed reduction and X-ray powder diffraction.A preliminary study on coke deposition and the deterioration of catalysts properties was carried out,by analyzing the tested catalysts through temperature programmed oxidation of coke,transmission electron microscopy,and N_(2) adsorption-desorption.Among the supports tested,ZrO_(2) showed the best performance,attaining conversion and H_(2) production values of 92.2% and 12.8 wt%,respectively.Concerning promoted catalysts,they led to similar conversion values(around 90%),but significant differences were observed in H_(2) production.Thus,higher H_(2) productions were obtained on the Ni/La_(2)O_(3)-Al_(2)O_(3) catalyst(12.1 wt%)than on CeO_(2) promoted catalysts due to La_(2)O_(3) capability for enhancing water adsorption on the catalyst surface.展开更多
It is economical to perform methane and carbon dioxide reforming(DRM)under industrially relevant high-pressure conditions,but the harsh operation condition poses a grand challenge for coke-resistant catalyst design.He...It is economical to perform methane and carbon dioxide reforming(DRM)under industrially relevant high-pressure conditions,but the harsh operation condition poses a grand challenge for coke-resistant catalyst design.Here,we propose to boost the coke-tolerance of Co catalyst by applying a contact potential introduced by immiscible Ag clusters.We demonstrate that Co clusters separated by neighboring Ag on Yttria-stabilized zirconia(YSZ)support can serve as a coke-and sintering-resistant DRM catalyst under diluent gas-free,stoichiometric CH_(4) and CO_(2) feeding,1123 K and 20 bar.Since immiscible metals are ubiquitous and metal contact influences surface work function in general,this new design concept may have general implications for tailoring catalytic properties of metals.展开更多
Under the driving goal of carbon neutrality,blogas reforming technology has garnered significant attention due to its ability to convert greenhouse gases(CH_(4)/CO_(2))into syngas(H_(2)/CO).Conventional nickel-based c...Under the driving goal of carbon neutrality,blogas reforming technology has garnered significant attention due to its ability to convert greenhouse gases(CH_(4)/CO_(2))into syngas(H_(2)/CO).Conventional nickel-based catalysts suffer from issues such as carbon deposition,sintering and sulfur poisoning.Non-nickel-based perovskite materials,with their tunable crystal structure,dynamic oxygen vacancy characteristics,and excellent anti-coking/anti-sulfur performance,have emerged as a promising alternative.This review systematically summarizes the design for non-nickel-based perovskite materials,including optimizing lattice oxygen migration ability and active site stability by A/B site doping,defect engineering and heterojunction construction.The enhancing the conversion rate of CH_(4)/CO_(2) by using the carbon oxidation mechanism mediated by oxygen vacancies,and maintaining good durability in complex biogas environments containing H_(2)S,NH_(3),etc.The photo-thermal synergistic catalysis further improves the reaction efficiency through energy coupling.However,challenges such as long-term operational stability(high-temperature lattice reconstruction),the cost of large-scale preparation and the synergistic poisoning effect of sulfur and water are still challenges for practical application.In the future,it is necessary to combine high-throughput computation,in situ characterization and multi-technology coupling to promote the leap of non-nickel-based perovskites materials from laboratory to industrial biogas reforming units.展开更多
CO_(2) and CH_(4) as major causes of global warming could both be eliminated to produce syngas undermild conditions through dry reforming methane driven by electromagnetic induction heating(EMIH-controlled DRM).Using ...CO_(2) and CH_(4) as major causes of global warming could both be eliminated to produce syngas undermild conditions through dry reforming methane driven by electromagnetic induction heating(EMIH-controlled DRM).Using EMIH-configured characterization and density functional theory,it is shownthat the EMIH-induced negative electric field at the electromagnetic interface facilitates CO_(2) dissociation and atomic oxygen transfer,which is the source of the promoting effect of EMIH.By employing pure H2 in a one-step high-temperature reduction process,the interfacial effect between the NiMgAl compound and the Fe fiber could be improved,thereby increasing the influence of the EMIH-induced electric field.Consequently,the R-NiMgAl/Fe fiber catalyst with EMIH achieves about 90%conversions of CH_(4) and CO_(2) at 500℃,while traditional heating-driven DRM on R-NiMgAl requires 700℃ to accomplish the same result.展开更多
In the grand tapestry of the global energy transition,the quest for scalable hydrogen economies emerges as a pivotal thread,weaving together the dual imperatives of decarbonization and industrial pragmatism.Yet,in its...In the grand tapestry of the global energy transition,the quest for scalable hydrogen economies emerges as a pivotal thread,weaving together the dual imperatives of decarbonization and industrial pragmatism.Yet,in its present form,hydrogen production remains deeply entwined with carbon emissions.展开更多
Developing efficient photocatalysts to address collaborative energy and environmental crises still faces significant challenges.In this report,we present a highly efficient MXene–based photocatalyst,which is combined...Developing efficient photocatalysts to address collaborative energy and environmental crises still faces significant challenges.In this report,we present a highly efficient MXene–based photocatalyst,which is combined with MoS_(2)nano patches and TiO_(2)/Ti_(3)C_(2)(TTC)nanowires through hydrothermal treatment.Of all the composites tested,the optimized photocatalyst gave a remarkable H_(2)and revolving polylactic acid(PLA)into pyruvic acid(PA).Achieving a remarkable H_(2)evolution rate of 637.1 and 243.2μmol g^(−1)h^(−1),in the presence of TEOA and PLA as a sacrificial reagent under UV-vis(λ≥365 nm)light irradiation.The improved photocatalytic activity is a result of the combination of dual cocatalyst on the surface of TTC photocatalyst,which create an ideal synergistic effect for the generation of PA and the production of H_(2)simultaneously.The MoS_(2)TiO_(2)/Ti_(3)C_(2)(MTT)composite can generate more photoexcited charge carriers,leading to the generation of more active radicals,which may enhance the system's photocatalytic activity.This work aims at demonstrating its future significance and guide the scientific community towards a more efficient approach to commercializing H_(2)through photocatalysis.展开更多
The catalytic steam reforming(SR)of biomass-derived organic compounds could be considered as a promising route to generate H_(2)fuel.This work aimed to achieve efficient H_(2)production by the SR of aqueous products o...The catalytic steam reforming(SR)of biomass-derived organic compounds could be considered as a promising route to generate H_(2)fuel.This work aimed to achieve efficient H_(2)production by the SR of aqueous products obtained from the hydrothermal conversion process of lignocellulosic biomass.The catalytic SR was studied over 15Ni/NiAl_(2)O_(4)for model compound mixtures composed of furfural,levulinic acid,and formic acid.At a reaction temperature of 800℃,the high H_(2)yield of 93.8%was achieved.Bimetallic Ni-Cu and Ni-Co catalysts supported by NiAl_(2)O_(4)were synthesized to optimize the SR performance in the presence of H_(2)SO_(4)as impurity.The Ni-Co and Cu-Ni alloys formed on the bimetallic catalysts during calcination and reduction were verified.The results revealed that the alloys formation improved the resistance of catalysts to oxidation and H_(2)SO_(4),thus weakening the catalyst deactivation during the SR process.Importantly,the catalytic SR was successfully applied to convert aqueous products from the hydrothermal conversion of pine sawdust.This study provides an encouraging route for upgrading biomass into high-value fuels.展开更多
In the past decade,dry reforming of methane(DRM)has garnered increasing interest as it converts CH_(4)and CO_(2),two typical greenhouse gases,into synthesis gas(H_(2)and CO)for the production of high-value-added chemi...In the past decade,dry reforming of methane(DRM)has garnered increasing interest as it converts CH_(4)and CO_(2),two typical greenhouse gases,into synthesis gas(H_(2)and CO)for the production of high-value-added chemicals and fuels.Nickel-based DRM catalysts,renowned for their high activity and low cost,however,encounter challenges such as severe deactivation from sintering and carbon deposition.Herein,a surrounded NiO@NiAlO precursor derived from Ni(OH)_(2)nanosheets was modified at both the core and shell interfaces with MgO via wet impregnation.The obtained 0.8MgO^(WI)/Ni@NiAlO catalyst achieved a high CH_(4)reaction rate of~177 mmol gNi^(-1)min^(-1)and remained stable for 50 h at 600℃without coke formation.In sharp contrast,other Mg-doped catalysts(MgO modified the core or shell interfaces)and the catalyst without Mg-doping deactivated within 10 h due to coking or Ni particle sintering.The Ni/MgNiO_(2)interfaces and abundant oxygen vacancies(O_(v))generated by Mg-doping contributed to the outstanding resistance to sintering&coking as well as the superior activity and stability of the 0.8MgO^(WI)/Ni@NiAlO catalyst.In-situ investigation further unveiled the reaction mechanism:the activation of CO_(2)via adsorption on O_(v)generates active oxygen species(O^(*)),which reacts with CH_(x)^(*)intermediates formed by the dissociation of CH_(4)on Ni sites,yielding CO and H_(2).This work not only fabricates coke-free and high-stability Ni-based DRM catalysts via interface engineering but also provides insights and a new strategy for the design of high-efficiency and stable catalysts for DRM.展开更多
Photothermal catalytic methane dry reforming(DRM)technology can convert greenhouse gases(i.e.CH_(4)and CO_(2))into syngas(i.e.H_(2)and CO),providing more opportunities for reducing the greenhouse effect and achieving ...Photothermal catalytic methane dry reforming(DRM)technology can convert greenhouse gases(i.e.CH_(4)and CO_(2))into syngas(i.e.H_(2)and CO),providing more opportunities for reducing the greenhouse effect and achieving carbon neutrality.In the DRM field,Ni-based catalysts attract wide attention due to their low cost and high activity.However,the carbon deposition over Ni-based catalysts always leads to rapid deactivation,which is still a main challenge.To improve the long-term stability of Ni-based catalysts,this work proposes a carbon-atom-diffusion strategy under photothermal conditions and investigates its effect on a Zn-doped Ni-based photothermal catalyst(Ni_(3)Zn@CeO_(2)).The photothermal catalytic behavior of Ni_(3)Zn@CeO_(2)can maintain more than 70 h in DRM reaction.And the photocatalytic DRM activity of Ni_(3)Zn@CeO_(2)is 1.2 times higher than thermal catalytic activity.Density functional theory(DFT)calculation and experimental characterizations indicate that Ni_(3)Zn promotes the diffusion of carbon atoms into the Ni_(3)Zn to form the Ni_(3)ZnC0.7 phase with body-centered cubic(bcc)structure,thus inhibiting carbon deposition.Further,in-situ diffuse reflectance infrared Fourier transform(DRIFT)spectroscopy and DFT calculation prove Ni_(3)Zn@CeO_(2)benefits the CH_(4)activation and inhibits the carbon deposition during the DRM process.Through inducing carbon atoms diffusion within the Ni_(3)Zn lattice,this work provides a straightforward and feasible strategy for achieving efficient photothermal catalytic DRM and even other CH_(4)conversion implementations with long-term stability.展开更多
Developing cost-effective and high-performance catalyst systems for dry reforming of methane(DRM)is crucial for producing hydrogen(H_(2))sustainably.Herein,we investigate using iron(Fe)as a promoter and major alumina ...Developing cost-effective and high-performance catalyst systems for dry reforming of methane(DRM)is crucial for producing hydrogen(H_(2))sustainably.Herein,we investigate using iron(Fe)as a promoter and major alumina support in Ni-based catalysts to improve their DRM performance.The addition of iron as a promotor was found to add reducible iron species along with reducible NiO species,enhance the basicity and induce the deposition of oxidizable carbon.By incorporating 1 wt.%Fe into a 5Ni/10ZrAl catalyst,a higher CO_(2) interaction and formation of reducible"NiO-species having strong interaction with support"was observed,which led to an∼80%H_(2) yield in 420 min of Time on Stream(TOS).Further increasing the Fe content to 2 wt.%led to the formation of additional reducible iron oxide species and a noticeable rise in H_(2) yield up to 84%.Despite the severe weight loss on Fe-promoted catalysts,high H_(2) yield was maintained due to the proper balance between the rate of CH_(4) decomposition and the rate of carbon deposit diffusion.Finally,incorporating 3 wt.%Fe into the 5Ni/10ZrAl catalyst resulted in the highest CO_(2) interaction,wide presence of reducible NiO-species,minimumgraphitic deposit and an 87%H_(2) yield.Our findings suggest that ironpromoted zirconia-alumina-supported Ni catalysts can be a cheap and excellent catalytic system for H_(2) production via DRM.展开更多
Ni-based catalysts hold great potential in the light-driven dry reforming of methane(DRM)for syngas production due to their low cost and comparable catalytic performance to conventional noble-metal catalysts.However,t...Ni-based catalysts hold great potential in the light-driven dry reforming of methane(DRM)for syngas production due to their low cost and comparable catalytic performance to conventional noble-metal catalysts.However,the currently available Ni-based catalysts are confronted with low light-driven DRM efficiency and poor stability attributed to the coking.Herein,an atomically dispersed Ni-loaded CeO_(2)(Ni/CeO_(2))for light-drivenDRMis prepared by employing a polyol-mediated doping method to allow the high loading concentration of Ni on the CeO_(2),which overcomes the conventional atomically dispersed metal problem of low loading content.The atomically dispersed nature of the Ni can induce enormous CH4 activation sites for the reaction and photothermal effects for driving the reaction,while the CeO_(2) can facilitateCO_(2) activation.Therefore,the optimized atomically dispersed Ni-loaded CeO_(2) demonstrates an excellent light-drivenDRMperformance forH_(2)(626.5 mmol gcat^(-1) h^(-1))and CO(728.5 mmol gcat^(-1) h^(-1))production.More importantly,the optimized sample sustains its DRM performance after 100 h of continuous test,and such excellent stability of the presence of enormous Ni–O pairs can prevent the rapid conversion of CH_(x) intermediates into coke.This work demonstrates the meticulous design of non-noble metal catalysts for the lightdriven DRM with both high performance and stability.展开更多
Engineering the local electronic structure of atomic-dispersed catalytic sites plays a critical role in selective photocatalysis.Here,we show the regulation of local electronic structure of atomic-dispersed Ni sites b...Engineering the local electronic structure of atomic-dispersed catalytic sites plays a critical role in selective photocatalysis.Here,we show the regulation of local electronic structure of atomic-dispersed Ni sites by forming oxygen-bridged diatomic Ni-O-Ni confined in MOF-derived TiO_(2)(O-Ni_(2)/TiO_(2))via oxalic acid chelation.Among them,MOF-derived TiO_(2)scaffold provides a highly porous structure,supporting highly exposed active sites of Ni-O-Ni dimers linked by oxygen bridges.Density functional theory calculations show that the Ni-O-Ni sites regulate the local electronic structure of Ni sites,promoting the adsorption and activation of reactant molecules.Ultrafast spectroscopy shows that,in comparison with monomeric Ni/TiO_(2),the strong interaction in dimeric O-Ni_(2)/TiO_(2)tends to bring forth a more pronounced suppression of photogenerated electron-hole recombination,beneficial for achieving better charge separation and transfer as desired.As a direct outcome,the O-Ni_(2)/TiO_(2)photocatalyst has shown enhanced photocatalytic activity and selectivity in glycerol reforming reaction,with the average rates of H_(2)and CO evolution attaining as high as 2542.6 and 361.7μmol g^(-1)h^(-1),respectively,along with a remarkable selectivity of96.1%towards the syngas production(under a 365-nm light irradiation).Notably,the H_(2)and CO yields of the O-Ni_(2)/TiO_(2)photocatalyst are 3.9 and 6.7 times higher than those of the Ni/TiO_(2)photocatalyst,respectively.This study highlights the beneficial role of engineering the local electronic structure of atomicdispersed catalytic sites and provides an effective way for selective photocatalytic biomass conversion.展开更多
Energy shortages and global warming are driving the focus on the greenhouse gases CH_(4)and CO_(2).The main reason why dry reforming of methane(DRM)has yet to be industrialized is its catalytic tendency to deactivate ...Energy shortages and global warming are driving the focus on the greenhouse gases CH_(4)and CO_(2).The main reason why dry reforming of methane(DRM)has yet to be industrialized is its catalytic tendency to deactivate due to carbon deposition or sintering.Single-atom Ni/CeO_(2)catalysts with suitable metalsupport interactions may provide a new strategy for developing highly active and coking-resistant nickel-based catalysts.In this work,we investigated the properties of the catalytic models of singleatom Ni loaded on CeO_(2)(111),CeO_(2)(110)and CeO_(2)(100),as well as their catalytic DRM performance with the density functional theory method(DFT).The interaction of CeO_(2)with different low-index crystal planes and single-atom Ni can be explained by the anchoring effect of surface O ions on Ni.Adsorption energies,growth patterns of Ni clusters,and migration studies of Ni atoms all indicate that the CeO_(2)(100)surface has the strongest anchoring effect on isolated Ni atoms,followed by the CeO_(2)(110)surface,with the CeO_(2)(111)surface being the weakest,Methane activation studies have shown that the activation ability of Ni_(1)/CeO_(2)(110)for methane strongly depends on the coordination environment of Ni,By contrast,methane activation by Ni on Ni_(1)/CeO_(2)(111)exhibits better activity and stability.Moreover,the Ni—CeO_(2)interaction correlates well with the DRM reaction performance.Interactions that are too strong anchor Ni atoms well but are not optimal for DRM activity.Ni_(1)/CeO_(2)(110)has relatively moderate interactions,promotes the^(*)CH_(4)→^(*)CH process,and has good resistance to carbon deposition.The metalsupport interaction-DRM reactivity(or stability)relationship is vital for the design of"super"highactivity and high-stability DRM catalysts.展开更多
Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering ...Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering applications.In this study,the Ce_(x)Zr_(1-x)O_(2)/ZSM-5 composites with different oxygen vacancy concentrations were synthesized by tuning the Ce/Zr ratio,followed by the deposition of metal Ni to island-like Ce_(x)Zr_(1-x)O_(2)on ZSM-5,forming a variety of Ni-Ce_(x)Zr_(1-x)O_(2)/ZSM-5 catalysts,which were applied for the DRM reaction under 750◦C.Combined with various characterizations,it was found that the oxygen vacancy concentration illustrated the volcanic tendency with the decreased Ce/Zr ratio,and the interaction between metal Ni and Ce_(x)Zr_(1-x)O_(2)exhibited a positive relationship with oxygen vacancy concentration.The enhanced between Ni and Ce_(x)Zr_(1-x)O_(2)interaction could improve the strength and amount of Ni-O-M(M=Ce/Zr)species,making the d-band centers of catalysts closer to the Fermi energy level,which was beneficial to the CH4 and CO_(2) activation,along with the improved capacity to resist sintering and coking.Especially,the C1Z3(Ni-Ce0.25Zr0.75O_(2)/ZSM-5)catalyst with the Ce/Zr ratio of 1/3 demonstrated the optimal catalytic performance with 91.9%CH4 and 93.8%CO_(2) conversions within 50 h,accompanied by the best structural and catalytic stability after 100 h.In-situ DRIFTS was employed to study the reaction path and mechanism,discovering that significant amounts of strengthened Ni-O-M species were conducive to activating adsorbed CH4 and CO_(2),and desorbing the linear CO species.展开更多
Li_(6)ZnO_(4)was chemically modified by nickel addition,in order to develop different compositions of the solid solution Li_(6)Zn_(1-x)Ni_(x)O_(4).These materials were evaluated bifunctionally;analyzing their CO_(2)ca...Li_(6)ZnO_(4)was chemically modified by nickel addition,in order to develop different compositions of the solid solution Li_(6)Zn_(1-x)Ni_(x)O_(4).These materials were evaluated bifunctionally;analyzing their CO_(2)capture performances,aswell as on their catalytic properties for H_(2)production via dry reforming of methane(DRM).The crystal structures of Li_(6)Zn_(1-x)Ni_(x)O_(4)solid solution samples were determined through X-ray diffraction,which confirmed the integration of nickel ions up to a concentration around 20 mol%,meanwhile beyond this value,a secondary phase was detected.These results were supported by XPS and TEM analyses.Then,dynamic and isothermal thermogravimetric analyses of CO_(2)capture revealed that Li_(6)Zn_(1-x)Ni_(x)O_(4)solid solution samples exhibited good CO_(2)chemisorption efficiencies,similarly to the pristine Li_(6)ZnO_(4)chemisorption trends observed.Moreover,a kinetic analysis of CO_(2)isothermal chemisorptions,using the Avrami-Erofeev model,evidenced an increment of the constant rates as a function of the Ni content.Since Ni^(2+)ions incorporation did not reduce the CO_(2)capture efficiency and kinetics,the catalytic properties of thesematerialswere evaluated in the DRM process.Results demonstrated that nickel ions favored hydrogen(H_(2))production over the pristine Li_(6)ZnO_(4)phase,despite a second H2 production reaction was determined,methane decomposition.Thereby,Li_(6)Zn_(1-x)Ni_(x)O_(4)ceramics can be employed as bifunctional materials.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52004339)the Key Research and Development Project of Hunan Province,China(No.2022SK2075)+1 种基金China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202216)Central South University Graduate Student Independent Exploration and Innovation Project(2024ZZTS0378).
文摘The self-reforming of coke oven gas(COG)in a gas-based shaft furnace was investigated,employing metallized iron as a catalyst.Thermodynamic analyses,supported by FactSage 8.3 calculations and regression modeling,were used to investigate the effects of temperature(700–1100℃),CO_(2)(3%–10%),and H_(2)O(1%–9%)concentrations on CH_(4) conversion efficiency.Results indicate that CH_(4) conversion exceeds 90%at temperatures above 1000℃,with CO_(2) and H_(2)O concentrations at 9%and 5%,respectively.During the reforming process,introducing CO_(2) provides additional oxygen,facilitating the oxidation of CH_(4),while H_(2)O enhances H_(2) production through the steam reforming pathway.Experimental findings reveal a CH_(4) conversion of 85.83%with a H_(2)/CO ratio of 5.44 at 1050℃.In addition,an optimal H_(2)O concentration of 6%yields the highest CH_(4) conversion of 84.24%,while CO_(2) exhibits minimal effects on promoting the reforming process.Increasing the metallization rate of pellets from 43%to 92%significantly enhances CH_(4) reforming.This is mainly due to the fact that metallized iron is vital in promoting CH_(4) dissociation and improving syngas yield by providing active sites for the redox cycle of CO_(2) and H_(2)O.
基金supported by the National Key R&D Program of China(No.2024YFB4007501)the Natural Science Foundation of Jiangsu Province(No.BK20240109)the project of Jiangsu Key Laboratory for Clean Utilization of Carbon Resources(No.BM2024007).
文摘Low-concentration coal mine methane(LC-CMM),which is predominantly composed of methane,serves as a clean and low-carbon energy resource with significant potential for utilization.Utilizing LC-CMM as fuel for solid oxide fuel cells(SOFCs)represents an efficient and promising strategy for its effective utilization.However,direct application in Ni-based anodes induces carbon deposition,which severely degrades cell performance.Herein,a medium-entropy oxide Sr_(2)FeNi_(0.1)Cr_(0.3)Mn_(0.3)Mo_(0.3)O_(6−δ)(SFNCMM)was developed as an anode internal reforming catalyst.Following reduction treatment,FeNi_(3) nano-alloy particles precipitate on the surface of the material,thereby significantly enhancing its catalytic activity for LC-CMM reforming process.The catalyst achieved a methane conversion rate of 53.3%,demonstrating excellent catalytic performance.Electrochemical evaluations revealed that SFNCMM-Gd_(0.1)Ce_(0.9)O_(2−δ)(GDC)with a weight ratio of 7:3 exhibited superior electrochemical performance when employed as the anodic catalytic layer.With H_(2) and LC-CMM as fuels,the single cell achieved maximum power densities of 1467.32 and 1116.97 mW·cm^(−2) at 800℃,respectively,with corresponding polarization impedances of 0.17 and 1.35Ω·cm^(2).Furthermore,the single cell maintained stable operation for over 100 h under LC-CMM fueling without significant carbon deposition,confirming its robust resistance to carbon formation.These results underscore the potential of medium-entropy oxides as highly effective catalytic layers for mitigating carbon deposition in SOFCs.
文摘The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methanereforming(SMR)and ship-based carbon capture(SBCC).The first refers to the common practice used to obtainhydrogen from methane(often derived from natural gas),where steam reacts with methane to produce hydrogenand carbon dioxide(CO_(2)).The second refers to capturing the CO_(2) generated during the SMR process on boardships.By capturing and storing the carbon emissions,the process significantly reduces its environmental impact,making the hydrogen production“blue,”as opposed to“grey”(which involves CO_(2) emissions without capture).For the SMR process,the analysis reveals that increasing the reformer temperature enhances both the processperformance and CO_(2) emissions.Conversely,a higher steam-to-carbon(s/c)ratio reduces hydrogen yield,therebydecreasing thermal efficiency.The study also shows that preheating the air and boil-off gas(BOG)before theyenter the combustion chamber boosts overall efficiency and curtails CO_(2) emissions.In the SBCC process,puremonoethanolamine(MEA)is employed to capture the CO_(2) generated by the exhaust gases from the SMR process.The results indicate that with a 90%CO_(2) capture rate,the associated heat consumption amounts to 4.6 MJ perkilogram of CO_(2) captured.This combined approach offers a viable pathway to produce blue hydrogen on LNGcarriers while significantly reducing the carbon footprint.
文摘CeO_(2) based semiconductor are widely used in solar-driven photothermal catalytic dry reforming of methane(DRM)reaction,but still suffer from low activity and low light utilization efficiency.This study developed graphite-CeO_(2) interfaces to enhance solar-driven photothermal catalytic DRM.Compared with carbon nanotubes-modified CeO_(2)(CeO_(2)-CNT),graphite-modified CeO_(2)(CeO_(2)-GRA)constructed graphite-CeO_(2) interfaces with distortion in CeO_(2),leading to the formation abundant oxygen vacancies.These graphite-CeO_(2) interfaces with oxygen vacancies enhanced optical absorption and promoted the generation and separation of photogenerated carriers.The high endothermic capacity of graphite elevated the catalyst surface temperature from 592.1−691.3℃,boosting light-to-thermal conversion.The synergy between photogenerated carriers and localized heat enabled Ni/CeO_(2)-GRA to achieve a CO production rate of 9985.6 mmol/(g·h)(vs 7192.4 mmol/(g·h)for Ni/CeO_(2))and a light-to-fuel efficiency of 21.8%(vs 13.8%for Ni/CeO_(2)).This work provides insights for designing graphite-semiconductor interfaces to advance photothermal catalytic efficiency.
基金supported by the Natural Science Foundation of Shanxi Province(202203021221155)the Foundation of National Key Laboratory of High Efficiency and Low Carbon Utilization of Coal(J23-24-902)。
文摘With ongoing global warming and increasing energy demands,the CH_(4)-CO_(2)reforming reaction(dry reforming of methane,DRM)has garnered significant attention as a promising carbon capture and utilization technology.Nickel-based catalysts are renowned for their outstanding activity and selectivity in this process.The impact of metal-support interaction(MSI),on Ni-based catalyst performance has been extensively researched and debated recently.This paper reviews the recent research progress of MSI on Ni-based catalysts and their characterization and modulation strategies in catalytic reactions.From the perspective of MSI,the effects of different carriers(metal oxides,carbon materials and molecular sieves,etc.)are introduced on the dispersion and surface structure of Ni active metal particles,and the effect of MSI on the activity and stability of DRM reactions on Ni-based catalysts is discussed in detail.Future research should focus on better understanding and controlling MSI to improve the performance and durability of nickel-based catalysts in CH_(4)-CO_(2)reforming,advancing cleaner energy technologies.
文摘High density polyethylene(HDPE)pyrolysis and in-line oxidative steam reforming was carried out in a two-step reaction system consisting of a conical spouted bed reactor and a fluidized bed reactor.Continuous plastic pyrolysis was conducted at 550℃ and the volatiles formed were fed in-line to the oxidative steam reforming step(space-time 3.12 gcat min gHDPE−1;ER=0.2 and steam/plastic=3)operating at 700℃.The influence Ni based reforming catalyst support(Al_(2)O_(3),ZrO_(2),SiO_(2))and promoter(CeO_(2),La_(2)O_(3))have on HDPE pyrolysis volatiles conversion and H_(2) production was assessed.The catalysts were prepared by the wet impregnation and they were characterized by means of N_(2) adsorption-desorption,X-ray fluorescence,temperature-programmed reduction and X-ray powder diffraction.A preliminary study on coke deposition and the deterioration of catalysts properties was carried out,by analyzing the tested catalysts through temperature programmed oxidation of coke,transmission electron microscopy,and N_(2) adsorption-desorption.Among the supports tested,ZrO_(2) showed the best performance,attaining conversion and H_(2) production values of 92.2% and 12.8 wt%,respectively.Concerning promoted catalysts,they led to similar conversion values(around 90%),but significant differences were observed in H_(2) production.Thus,higher H_(2) productions were obtained on the Ni/La_(2)O_(3)-Al_(2)O_(3) catalyst(12.1 wt%)than on CeO_(2) promoted catalysts due to La_(2)O_(3) capability for enhancing water adsorption on the catalyst surface.
文摘It is economical to perform methane and carbon dioxide reforming(DRM)under industrially relevant high-pressure conditions,but the harsh operation condition poses a grand challenge for coke-resistant catalyst design.Here,we propose to boost the coke-tolerance of Co catalyst by applying a contact potential introduced by immiscible Ag clusters.We demonstrate that Co clusters separated by neighboring Ag on Yttria-stabilized zirconia(YSZ)support can serve as a coke-and sintering-resistant DRM catalyst under diluent gas-free,stoichiometric CH_(4) and CO_(2) feeding,1123 K and 20 bar.Since immiscible metals are ubiquitous and metal contact influences surface work function in general,this new design concept may have general implications for tailoring catalytic properties of metals.
基金Sichuan Science and Technology Program (2023ZDZX0005).
文摘Under the driving goal of carbon neutrality,blogas reforming technology has garnered significant attention due to its ability to convert greenhouse gases(CH_(4)/CO_(2))into syngas(H_(2)/CO).Conventional nickel-based catalysts suffer from issues such as carbon deposition,sintering and sulfur poisoning.Non-nickel-based perovskite materials,with their tunable crystal structure,dynamic oxygen vacancy characteristics,and excellent anti-coking/anti-sulfur performance,have emerged as a promising alternative.This review systematically summarizes the design for non-nickel-based perovskite materials,including optimizing lattice oxygen migration ability and active site stability by A/B site doping,defect engineering and heterojunction construction.The enhancing the conversion rate of CH_(4)/CO_(2) by using the carbon oxidation mechanism mediated by oxygen vacancies,and maintaining good durability in complex biogas environments containing H_(2)S,NH_(3),etc.The photo-thermal synergistic catalysis further improves the reaction efficiency through energy coupling.However,challenges such as long-term operational stability(high-temperature lattice reconstruction),the cost of large-scale preparation and the synergistic poisoning effect of sulfur and water are still challenges for practical application.In the future,it is necessary to combine high-throughput computation,in situ characterization and multi-technology coupling to promote the leap of non-nickel-based perovskites materials from laboratory to industrial biogas reforming units.
基金supported by the National Nature Science Foundation of China(Nos.22176187 and 22376193)the STS Program Supporting Project of Fujian Province&CAS(No.2023T3070)+1 种基金the Youth Innovation Promotion Association of CAS(No.2021304)the Guiding Project of Seizing the Commanding Heights of“Self-purifying City”(No.IUE-CERAE-202403).
文摘CO_(2) and CH_(4) as major causes of global warming could both be eliminated to produce syngas undermild conditions through dry reforming methane driven by electromagnetic induction heating(EMIH-controlled DRM).Using EMIH-configured characterization and density functional theory,it is shownthat the EMIH-induced negative electric field at the electromagnetic interface facilitates CO_(2) dissociation and atomic oxygen transfer,which is the source of the promoting effect of EMIH.By employing pure H2 in a one-step high-temperature reduction process,the interfacial effect between the NiMgAl compound and the Fe fiber could be improved,thereby increasing the influence of the EMIH-induced electric field.Consequently,the R-NiMgAl/Fe fiber catalyst with EMIH achieves about 90%conversions of CH_(4) and CO_(2) at 500℃,while traditional heating-driven DRM on R-NiMgAl requires 700℃ to accomplish the same result.
基金financially supported by the National Natural Science Foundation of China(22225902)the National Key Research&Development Program of China(2022YFE0115900)。
文摘In the grand tapestry of the global energy transition,the quest for scalable hydrogen economies emerges as a pivotal thread,weaving together the dual imperatives of decarbonization and industrial pragmatism.Yet,in its present form,hydrogen production remains deeply entwined with carbon emissions.
文摘Developing efficient photocatalysts to address collaborative energy and environmental crises still faces significant challenges.In this report,we present a highly efficient MXene–based photocatalyst,which is combined with MoS_(2)nano patches and TiO_(2)/Ti_(3)C_(2)(TTC)nanowires through hydrothermal treatment.Of all the composites tested,the optimized photocatalyst gave a remarkable H_(2)and revolving polylactic acid(PLA)into pyruvic acid(PA).Achieving a remarkable H_(2)evolution rate of 637.1 and 243.2μmol g^(−1)h^(−1),in the presence of TEOA and PLA as a sacrificial reagent under UV-vis(λ≥365 nm)light irradiation.The improved photocatalytic activity is a result of the combination of dual cocatalyst on the surface of TTC photocatalyst,which create an ideal synergistic effect for the generation of PA and the production of H_(2)simultaneously.The MoS_(2)TiO_(2)/Ti_(3)C_(2)(MTT)composite can generate more photoexcited charge carriers,leading to the generation of more active radicals,which may enhance the system's photocatalytic activity.This work aims at demonstrating its future significance and guide the scientific community towards a more efficient approach to commercializing H_(2)through photocatalysis.
基金supported by the National Natural Science Foundation of China(52261135626).
文摘The catalytic steam reforming(SR)of biomass-derived organic compounds could be considered as a promising route to generate H_(2)fuel.This work aimed to achieve efficient H_(2)production by the SR of aqueous products obtained from the hydrothermal conversion process of lignocellulosic biomass.The catalytic SR was studied over 15Ni/NiAl_(2)O_(4)for model compound mixtures composed of furfural,levulinic acid,and formic acid.At a reaction temperature of 800℃,the high H_(2)yield of 93.8%was achieved.Bimetallic Ni-Cu and Ni-Co catalysts supported by NiAl_(2)O_(4)were synthesized to optimize the SR performance in the presence of H_(2)SO_(4)as impurity.The Ni-Co and Cu-Ni alloys formed on the bimetallic catalysts during calcination and reduction were verified.The results revealed that the alloys formation improved the resistance of catalysts to oxidation and H_(2)SO_(4),thus weakening the catalyst deactivation during the SR process.Importantly,the catalytic SR was successfully applied to convert aqueous products from the hydrothermal conversion of pine sawdust.This study provides an encouraging route for upgrading biomass into high-value fuels.
文摘In the past decade,dry reforming of methane(DRM)has garnered increasing interest as it converts CH_(4)and CO_(2),two typical greenhouse gases,into synthesis gas(H_(2)and CO)for the production of high-value-added chemicals and fuels.Nickel-based DRM catalysts,renowned for their high activity and low cost,however,encounter challenges such as severe deactivation from sintering and carbon deposition.Herein,a surrounded NiO@NiAlO precursor derived from Ni(OH)_(2)nanosheets was modified at both the core and shell interfaces with MgO via wet impregnation.The obtained 0.8MgO^(WI)/Ni@NiAlO catalyst achieved a high CH_(4)reaction rate of~177 mmol gNi^(-1)min^(-1)and remained stable for 50 h at 600℃without coke formation.In sharp contrast,other Mg-doped catalysts(MgO modified the core or shell interfaces)and the catalyst without Mg-doping deactivated within 10 h due to coking or Ni particle sintering.The Ni/MgNiO_(2)interfaces and abundant oxygen vacancies(O_(v))generated by Mg-doping contributed to the outstanding resistance to sintering&coking as well as the superior activity and stability of the 0.8MgO^(WI)/Ni@NiAlO catalyst.In-situ investigation further unveiled the reaction mechanism:the activation of CO_(2)via adsorption on O_(v)generates active oxygen species(O^(*)),which reacts with CH_(x)^(*)intermediates formed by the dissociation of CH_(4)on Ni sites,yielding CO and H_(2).This work not only fabricates coke-free and high-stability Ni-based DRM catalysts via interface engineering but also provides insights and a new strategy for the design of high-efficiency and stable catalysts for DRM.
文摘Photothermal catalytic methane dry reforming(DRM)technology can convert greenhouse gases(i.e.CH_(4)and CO_(2))into syngas(i.e.H_(2)and CO),providing more opportunities for reducing the greenhouse effect and achieving carbon neutrality.In the DRM field,Ni-based catalysts attract wide attention due to their low cost and high activity.However,the carbon deposition over Ni-based catalysts always leads to rapid deactivation,which is still a main challenge.To improve the long-term stability of Ni-based catalysts,this work proposes a carbon-atom-diffusion strategy under photothermal conditions and investigates its effect on a Zn-doped Ni-based photothermal catalyst(Ni_(3)Zn@CeO_(2)).The photothermal catalytic behavior of Ni_(3)Zn@CeO_(2)can maintain more than 70 h in DRM reaction.And the photocatalytic DRM activity of Ni_(3)Zn@CeO_(2)is 1.2 times higher than thermal catalytic activity.Density functional theory(DFT)calculation and experimental characterizations indicate that Ni_(3)Zn promotes the diffusion of carbon atoms into the Ni_(3)Zn to form the Ni_(3)ZnC0.7 phase with body-centered cubic(bcc)structure,thus inhibiting carbon deposition.Further,in-situ diffuse reflectance infrared Fourier transform(DRIFT)spectroscopy and DFT calculation prove Ni_(3)Zn@CeO_(2)benefits the CH_(4)activation and inhibits the carbon deposition during the DRM process.Through inducing carbon atoms diffusion within the Ni_(3)Zn lattice,this work provides a straightforward and feasible strategy for achieving efficient photothermal catalytic DRM and even other CH_(4)conversion implementations with long-term stability.
基金The authors would like to extend their sincere appreciation to Researchers Supporting Project number (RSP2023R368)King Saud University,Riyadh,Saudi Arabia.RK,NP,VKS acknowledge Indus University,Ahmedabad,for supporting research.Dr.Ahmed I.Osman and Prof.David W.Rooney wish to acknowledge the support of The Bryden Centre project (Project ID VA5048)。
文摘Developing cost-effective and high-performance catalyst systems for dry reforming of methane(DRM)is crucial for producing hydrogen(H_(2))sustainably.Herein,we investigate using iron(Fe)as a promoter and major alumina support in Ni-based catalysts to improve their DRM performance.The addition of iron as a promotor was found to add reducible iron species along with reducible NiO species,enhance the basicity and induce the deposition of oxidizable carbon.By incorporating 1 wt.%Fe into a 5Ni/10ZrAl catalyst,a higher CO_(2) interaction and formation of reducible"NiO-species having strong interaction with support"was observed,which led to an∼80%H_(2) yield in 420 min of Time on Stream(TOS).Further increasing the Fe content to 2 wt.%led to the formation of additional reducible iron oxide species and a noticeable rise in H_(2) yield up to 84%.Despite the severe weight loss on Fe-promoted catalysts,high H_(2) yield was maintained due to the proper balance between the rate of CH_(4) decomposition and the rate of carbon deposit diffusion.Finally,incorporating 3 wt.%Fe into the 5Ni/10ZrAl catalyst resulted in the highest CO_(2) interaction,wide presence of reducible NiO-species,minimumgraphitic deposit and an 87%H_(2) yield.Our findings suggest that ironpromoted zirconia-alumina-supported Ni catalysts can be a cheap and excellent catalytic system for H_(2) production via DRM.
基金financial support from the National Key R&D Program of China(2022YFE0126500)the National Natural Science Foundation of China(52261135635.52372165,U23A2091,22150610467)+1 种基金the Natural Science Foundation of Anhui Province(2308085MB32)the Scientific and Technological Research Council of Turkey(TUBITAK,122N434).
文摘Ni-based catalysts hold great potential in the light-driven dry reforming of methane(DRM)for syngas production due to their low cost and comparable catalytic performance to conventional noble-metal catalysts.However,the currently available Ni-based catalysts are confronted with low light-driven DRM efficiency and poor stability attributed to the coking.Herein,an atomically dispersed Ni-loaded CeO_(2)(Ni/CeO_(2))for light-drivenDRMis prepared by employing a polyol-mediated doping method to allow the high loading concentration of Ni on the CeO_(2),which overcomes the conventional atomically dispersed metal problem of low loading content.The atomically dispersed nature of the Ni can induce enormous CH4 activation sites for the reaction and photothermal effects for driving the reaction,while the CeO_(2) can facilitateCO_(2) activation.Therefore,the optimized atomically dispersed Ni-loaded CeO_(2) demonstrates an excellent light-drivenDRMperformance forH_(2)(626.5 mmol gcat^(-1) h^(-1))and CO(728.5 mmol gcat^(-1) h^(-1))production.More importantly,the optimized sample sustains its DRM performance after 100 h of continuous test,and such excellent stability of the presence of enormous Ni–O pairs can prevent the rapid conversion of CH_(x) intermediates into coke.This work demonstrates the meticulous design of non-noble metal catalysts for the lightdriven DRM with both high performance and stability.
基金supported by the National Key R&D Program of China(2022YFA1503003)the National Natural Science Foundation of China(U24A20550,52273264,22173090)+2 种基金the Youth Scienceof China(22409056)the Innovation Program for Quantum Science and Technology(2021ZD0303303)the Key Project of the Heilongjiang Provincial Natural Science Foundation(ZD2024B001)。
文摘Engineering the local electronic structure of atomic-dispersed catalytic sites plays a critical role in selective photocatalysis.Here,we show the regulation of local electronic structure of atomic-dispersed Ni sites by forming oxygen-bridged diatomic Ni-O-Ni confined in MOF-derived TiO_(2)(O-Ni_(2)/TiO_(2))via oxalic acid chelation.Among them,MOF-derived TiO_(2)scaffold provides a highly porous structure,supporting highly exposed active sites of Ni-O-Ni dimers linked by oxygen bridges.Density functional theory calculations show that the Ni-O-Ni sites regulate the local electronic structure of Ni sites,promoting the adsorption and activation of reactant molecules.Ultrafast spectroscopy shows that,in comparison with monomeric Ni/TiO_(2),the strong interaction in dimeric O-Ni_(2)/TiO_(2)tends to bring forth a more pronounced suppression of photogenerated electron-hole recombination,beneficial for achieving better charge separation and transfer as desired.As a direct outcome,the O-Ni_(2)/TiO_(2)photocatalyst has shown enhanced photocatalytic activity and selectivity in glycerol reforming reaction,with the average rates of H_(2)and CO evolution attaining as high as 2542.6 and 361.7μmol g^(-1)h^(-1),respectively,along with a remarkable selectivity of96.1%towards the syngas production(under a 365-nm light irradiation).Notably,the H_(2)and CO yields of the O-Ni_(2)/TiO_(2)photocatalyst are 3.9 and 6.7 times higher than those of the Ni/TiO_(2)photocatalyst,respectively.This study highlights the beneficial role of engineering the local electronic structure of atomicdispersed catalytic sites and provides an effective way for selective photocatalytic biomass conversion.
基金Project supported by the Major Science and Technology Projects in Yunnan Province(202302AG050005)。
文摘Energy shortages and global warming are driving the focus on the greenhouse gases CH_(4)and CO_(2).The main reason why dry reforming of methane(DRM)has yet to be industrialized is its catalytic tendency to deactivate due to carbon deposition or sintering.Single-atom Ni/CeO_(2)catalysts with suitable metalsupport interactions may provide a new strategy for developing highly active and coking-resistant nickel-based catalysts.In this work,we investigated the properties of the catalytic models of singleatom Ni loaded on CeO_(2)(111),CeO_(2)(110)and CeO_(2)(100),as well as their catalytic DRM performance with the density functional theory method(DFT).The interaction of CeO_(2)with different low-index crystal planes and single-atom Ni can be explained by the anchoring effect of surface O ions on Ni.Adsorption energies,growth patterns of Ni clusters,and migration studies of Ni atoms all indicate that the CeO_(2)(100)surface has the strongest anchoring effect on isolated Ni atoms,followed by the CeO_(2)(110)surface,with the CeO_(2)(111)surface being the weakest,Methane activation studies have shown that the activation ability of Ni_(1)/CeO_(2)(110)for methane strongly depends on the coordination environment of Ni,By contrast,methane activation by Ni on Ni_(1)/CeO_(2)(111)exhibits better activity and stability.Moreover,the Ni—CeO_(2)interaction correlates well with the DRM reaction performance.Interactions that are too strong anchor Ni atoms well but are not optimal for DRM activity.Ni_(1)/CeO_(2)(110)has relatively moderate interactions,promotes the^(*)CH_(4)→^(*)CH process,and has good resistance to carbon deposition.The metalsupport interaction-DRM reactivity(or stability)relationship is vital for the design of"super"highactivity and high-stability DRM catalysts.
基金the following financial supports:National Natural Science Foundation of China(22075225 and 22038011)Innovative Scientific Program of CNNC,State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology(MJNYSKL202401,MJNYSKL202404).
文摘Dry reforming of methane(DRM)has gained significant attention as a promising route to convert two major greenhouse gases(CO_(2) and CH4)to syngas.The development of efficient catalysts is critical for the engineering applications.In this study,the Ce_(x)Zr_(1-x)O_(2)/ZSM-5 composites with different oxygen vacancy concentrations were synthesized by tuning the Ce/Zr ratio,followed by the deposition of metal Ni to island-like Ce_(x)Zr_(1-x)O_(2)on ZSM-5,forming a variety of Ni-Ce_(x)Zr_(1-x)O_(2)/ZSM-5 catalysts,which were applied for the DRM reaction under 750◦C.Combined with various characterizations,it was found that the oxygen vacancy concentration illustrated the volcanic tendency with the decreased Ce/Zr ratio,and the interaction between metal Ni and Ce_(x)Zr_(1-x)O_(2)exhibited a positive relationship with oxygen vacancy concentration.The enhanced between Ni and Ce_(x)Zr_(1-x)O_(2)interaction could improve the strength and amount of Ni-O-M(M=Ce/Zr)species,making the d-band centers of catalysts closer to the Fermi energy level,which was beneficial to the CH4 and CO_(2) activation,along with the improved capacity to resist sintering and coking.Especially,the C1Z3(Ni-Ce0.25Zr0.75O_(2)/ZSM-5)catalyst with the Ce/Zr ratio of 1/3 demonstrated the optimal catalytic performance with 91.9%CH4 and 93.8%CO_(2) conversions within 50 h,accompanied by the best structural and catalytic stability after 100 h.In-situ DRIFTS was employed to study the reaction path and mechanism,discovering that significant amounts of strengthened Ni-O-M species were conducive to activating adsorbed CH4 and CO_(2),and desorbing the linear CO species.
基金This work was carried out in the framework of PAPIIT-UNAM(IN-205823)project.
文摘Li_(6)ZnO_(4)was chemically modified by nickel addition,in order to develop different compositions of the solid solution Li_(6)Zn_(1-x)Ni_(x)O_(4).These materials were evaluated bifunctionally;analyzing their CO_(2)capture performances,aswell as on their catalytic properties for H_(2)production via dry reforming of methane(DRM).The crystal structures of Li_(6)Zn_(1-x)Ni_(x)O_(4)solid solution samples were determined through X-ray diffraction,which confirmed the integration of nickel ions up to a concentration around 20 mol%,meanwhile beyond this value,a secondary phase was detected.These results were supported by XPS and TEM analyses.Then,dynamic and isothermal thermogravimetric analyses of CO_(2)capture revealed that Li_(6)Zn_(1-x)Ni_(x)O_(4)solid solution samples exhibited good CO_(2)chemisorption efficiencies,similarly to the pristine Li_(6)ZnO_(4)chemisorption trends observed.Moreover,a kinetic analysis of CO_(2)isothermal chemisorptions,using the Avrami-Erofeev model,evidenced an increment of the constant rates as a function of the Ni content.Since Ni^(2+)ions incorporation did not reduce the CO_(2)capture efficiency and kinetics,the catalytic properties of thesematerialswere evaluated in the DRM process.Results demonstrated that nickel ions favored hydrogen(H_(2))production over the pristine Li_(6)ZnO_(4)phase,despite a second H2 production reaction was determined,methane decomposition.Thereby,Li_(6)Zn_(1-x)Ni_(x)O_(4)ceramics can be employed as bifunctional materials.
