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
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
Ni/TiO_(2) catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO_(2) remains unclear.In this work,the rutile/anatase ratio in supports was successfully controlled by...Ni/TiO_(2) catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO_(2) remains unclear.In this work,the rutile/anatase ratio in supports was successfully controlled by varying the calcination temperature of anatase-TiO_(2).Structural characterizations revealed that a distinct TiO_(x) coating on the Ni nanoparticles(NPs)was evident for Ni/TiO_(2)-700 catalyst due to strong metal-support interaction.It is observed that the TiOx overlayer gradually disappeared as the ratio of rutile/anatase increased,thereby enhancing the exposure of Ni active sites.The exposed Ni sites enhanced visible light absorption and boosted the dissociation capability of CH4,which led to the much elevated catalytic activity for Ni/TiO_(2)-950 in which rutile dominated.Therefore,the catalytic activity of solar-driven DRM reaction was significantly influenced by the rutile/anatase ratio.Ni/TiO_(2)-950,characterized by a predominant rutile phase,exhibited the highest DRM reactivity,with remarkable H_(2) and CO production rates reaching as high as 87.4 and 220.2 mmol/(g·h),respectively.These rates were approximately 257 and 130 times higher,respectively,compared to those obtained on Ni/TiO_(2)-700 with anatase.This study suggests that the optimization of crystal structure of TiO_(2) support can effectively enhance the performance of photothermal DRM reaction.展开更多
This study investigates the dry reformation of methane(DRM)over Ni/Al_(2)O_(3)catalysts in a dielectric barrier discharge(DBD)non-thermal plasma reactor.A novel hybrid machine learning(ML)model is developed to optimiz...This study investigates the dry reformation of methane(DRM)over Ni/Al_(2)O_(3)catalysts in a dielectric barrier discharge(DBD)non-thermal plasma reactor.A novel hybrid machine learning(ML)model is developed to optimize the plasma-catalytic DRM reaction with limited experimental data.To address the non-linear and complex nature of the plasma-catalytic DRM process,the hybrid ML model integrates three well-established algorithms:regression trees,support vector regression,and artificial neural networks.A genetic algorithm(GA)is then used to optimize the hyperparameters of each algorithm within the hybrid ML model.The ML model achieved excellent agreement with the experimental data,demonstrating its efficacy in accurately predicting and optimizing the DRM process.The model was subsequently used to investigate the impact of various operating parameters on the plasma-catalytic DRM performance.We found that the optimal discharge power(20 W),CO_(2)/CH_(4)molar ratio(1.5),and Ni loading(7.8 wt%)resulted in the maximum energy yield at a total flow rate of∼51 mL/min.Furthermore,we investigated the relative significance of each operating parameter on the performance of the plasma-catalytic DRM process.The results show that the total flow rate had the greatest influence on the conversion,with a significance exceeding 35%for each output,while the Ni loading had the least impact on the overall reaction performance.This hybrid model demonstrates a remarkable ability to extract valuable insights from limited datasets,enabling the development and optimization of more efficient and selective plasma-catalytic chemical processes.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
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 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
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
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
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
Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawba...Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.展开更多
The increasing anthropogenic emissions of greenhouse gases(GHG)is encouraging extensive research in CO_(2)utilisation.Dry reforming of methane(DRM)depicts a viable strategy to convert both CO_(2)and CH4into syngas,a w...The increasing anthropogenic emissions of greenhouse gases(GHG)is encouraging extensive research in CO_(2)utilisation.Dry reforming of methane(DRM)depicts a viable strategy to convert both CO_(2)and CH4into syngas,a worthwhile chemical intermediate.Among the different active phases for DRM,the use of nickel as catalyst is economically favourable,but typically deactivates due to sintering and carbon deposition.The stabilisation of Ni at different loadings in cerium zirconate inorganic complex structures is investigated in this work as strategy to develop robust Ni-based DRM catalysts.XRD and TPR-H2analyses confirmed the existence of different phases according to the Ni loading in these materials.Besides,superficial Ni is observed as well as the existence of a CeNiO_(3)perovskite structure.The catalytic activity was tested,proving that 10 wt.%Ni loading is the optimum which maximises conversion.This catalyst was also tested in long-term stability experiments at 600and 800℃in order to study the potential deactivation issues at two different temperatures.At 600℃,carbon formation is the main cause of catalytic deactivation,whereas a robust stability is shown at 800℃,observing no sintering of the active phase evidencing the success of this strategy rendering a new family of economically appealing CO_(2)and biogas mixtures upgrading catalysts.展开更多
Coal pyrolysis integrated with dry reforming of low-carbon alkane(CP-DRA)is an effective way to improve tar yield.Ni/La_(2)O_(3)-ZrO_(2) with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition...Coal pyrolysis integrated with dry reforming of low-carbon alkane(CP-DRA)is an effective way to improve tar yield.Ni/La_(2)O_(3)-ZrO_(2) with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition and obtain high tar yield in CP-DRA.In this study,the fraction distribution and component of tars from CP-DRA and coal pyrolysis in N_(2) atmosphere(CP-N_(2))were characterized by using several methods to understand the effect of DRA on coal pyrolysis.The isotope trace method was also used to discuss the role of low-carbon alkane in CP-DRA.The results showed that the tar from CP-N_(2)is mainly composed of aliphatic compounds with more C_(al),H_(al) and CH+CH_(2),and the tar from CP-DRA contains more Car,Har,and CH_(3),and has lower weight-average molecular weight and more light tar content than CP-N_(2).A small amount of C_(2)H_(6) addition in CP-DRA will raise the ratio of H_(β) and CH+CH_(2).Electron paramagnetic resonance(EPR)analysis shows that the tar from CP-DRA has a higher radical concentration while the corresponding char has a lower radical concentration.The isotope trace experiment showed that alkanes provide·H,·CH_(3),etc.to stabilize the radicals from coal pyrolysis and result in more alkyl aromatic compounds during CP-DRA.展开更多
An energy production system consisting of a solar collector, biogas dry reforming reactor and solid oxide fuel cell (SOFC) was assumed to be installed in Kolkata, India. This study aims to understand the impact of cli...An energy production system consisting of a solar collector, biogas dry reforming reactor and solid oxide fuel cell (SOFC) was assumed to be installed in Kolkata, India. This study aims to understand the impact of climate conditions on the performance of solar collectors with different lengths of parabolic trough solar collector (dx) and mass flow rate of heat transfer fluid (m). In addition, this study has evaluated the amount of H2 produced by biogas dry reforming (GH2), the amount of power generated by SOFC (PSOFC) and the maximum number of possible households (N) whose electricity demand could be met by the energy system proposed, considering the performance of solar collector with the different dx and m. As a result, the optimum dx was found to be 4 m. This study revealed that the temperature of heat transfer fluid (Tfb) decreased with the increase in m. Tfb in March, April and May was higher than that in other months, while Tfb from June to December was the lowest. GH2, PSOFC and N in March, April and May were higher than those in other months, irrespective of m. The optimum m was 0.030 kg/s.展开更多
An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydr...An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydrothermal method and used as the support for a Ni catalyst for the dry reforming of methane （DRM） with CO2. ZrO2-ipch is a much better support than ZrO2-cs and the traditional ZrO2 irregular particles made by a simple precipitation method （ZrO2-ip）. The supported Ni catalyst on ZrO2-ipch （Ni/ZrO2-ipch） exhibited outstanding catalytic activity and coke-resistant stability compared to the ones on ZrO2-cs （Ni/ZrO2-cs） and ZrO2-ip （Ni/ZrO2-ip）. Ni/ZrO2-ip exhibited the worst catalytic performance. The origin of the significantly enhanced catalytic performance was revealed by characterization including XRD, N2 adsorption measurement （BET）, TEM, H2-TPR, CO chemisorption, CO2-TPD, XPS and TGA. The superior catalytic activity of Ni/ZrO2-ipch to Ni/ZrO2-cs or Ni/ZrO2-ip was ascribed to a higher Ni dispersion, increased reducibility, enhanced oxygen mo- bility, and more basic sites with a higher strength, which were due to the unique hierarchically structural morphology of the ZrO2-ipch support. Ni/ZrO2-ipch exhibited better stability for the DRM reaction than Ni/ZrO2-ip, which was ascribed to its higher resistance to Ni sintering due to a strengthened metal-support interaction and the confinement effect of the mesopores and coke deposition resistance. The higher coking resistance of Ni/ZrO2-ipch for the DRM reaction in comparison with Ni/ZrOz-ip orignated from the coke-removalabitity of the higher amount of lattice oxygen and more basic sites, confirmed by XPS and CO2-TPD analysis, and the stabilized Ni on the Ni/ZrO2-ipch catalyst by the confinement effect of the mesopores of the hierarchical ZrO2-ipch sup- port. The superior catalytic performance and coking resistance of the Ni/ZrO2-ipch catalyst makes it a promising candidate for synthesis gas production from the DRM reaction.展开更多
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The project was supported by the National Key R&D Program of China(2021YFF0500702)Natural Science Foundation of Shanghai(22JC1404200)+3 种基金Program of Shanghai Academic/Technology Research Leader(20XD1404000)Natural Science Foundation of China(U22B20136,22293023)Science and Technology Major Project of Inner Mongolia(2021ZD0042)the Youth Innovation Promotion Association of CAS。
文摘Ni/TiO_(2) catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO_(2) remains unclear.In this work,the rutile/anatase ratio in supports was successfully controlled by varying the calcination temperature of anatase-TiO_(2).Structural characterizations revealed that a distinct TiO_(x) coating on the Ni nanoparticles(NPs)was evident for Ni/TiO_(2)-700 catalyst due to strong metal-support interaction.It is observed that the TiOx overlayer gradually disappeared as the ratio of rutile/anatase increased,thereby enhancing the exposure of Ni active sites.The exposed Ni sites enhanced visible light absorption and boosted the dissociation capability of CH4,which led to the much elevated catalytic activity for Ni/TiO_(2)-950 in which rutile dominated.Therefore,the catalytic activity of solar-driven DRM reaction was significantly influenced by the rutile/anatase ratio.Ni/TiO_(2)-950,characterized by a predominant rutile phase,exhibited the highest DRM reactivity,with remarkable H_(2) and CO production rates reaching as high as 87.4 and 220.2 mmol/(g·h),respectively.These rates were approximately 257 and 130 times higher,respectively,compared to those obtained on Ni/TiO_(2)-700 with anatase.This study suggests that the optimization of crystal structure of TiO_(2) support can effectively enhance the performance of photothermal DRM reaction.
基金This project received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 813393the funding from the National Natural Science Foundation of China (No. 52177149)
文摘This study investigates the dry reformation of methane(DRM)over Ni/Al_(2)O_(3)catalysts in a dielectric barrier discharge(DBD)non-thermal plasma reactor.A novel hybrid machine learning(ML)model is developed to optimize the plasma-catalytic DRM reaction with limited experimental data.To address the non-linear and complex nature of the plasma-catalytic DRM process,the hybrid ML model integrates three well-established algorithms:regression trees,support vector regression,and artificial neural networks.A genetic algorithm(GA)is then used to optimize the hyperparameters of each algorithm within the hybrid ML model.The ML model achieved excellent agreement with the experimental data,demonstrating its efficacy in accurately predicting and optimizing the DRM process.The model was subsequently used to investigate the impact of various operating parameters on the plasma-catalytic DRM performance.We found that the optimal discharge power(20 W),CO_(2)/CH_(4)molar ratio(1.5),and Ni loading(7.8 wt%)resulted in the maximum energy yield at a total flow rate of∼51 mL/min.Furthermore,we investigated the relative significance of each operating parameter on the performance of the plasma-catalytic DRM process.The results show that the total flow rate had the greatest influence on the conversion,with a significance exceeding 35%for each output,while the Ni loading had the least impact on the overall reaction performance.This hybrid model demonstrates a remarkable ability to extract valuable insights from limited datasets,enabling the development and optimization of more efficient and selective plasma-catalytic chemical processes.
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.
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.
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.
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.
基金This work was financially supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(51888103)the National Key R&D Program of China(2021YFF0500700)Jiangsu Natural Science Foundation Project(BE2022024 and BK20202008).
文摘Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.
基金supported by grant PID2019-108502RJ-I00 and grant IJC2019-040560-I both funded by MCIN/AEI/10.13039/501100011033RYC2018-024387-I funded by MCIN/AEI/10.13039/501100011033 and by ESF Investing in your future。
文摘The increasing anthropogenic emissions of greenhouse gases(GHG)is encouraging extensive research in CO_(2)utilisation.Dry reforming of methane(DRM)depicts a viable strategy to convert both CO_(2)and CH4into syngas,a worthwhile chemical intermediate.Among the different active phases for DRM,the use of nickel as catalyst is economically favourable,but typically deactivates due to sintering and carbon deposition.The stabilisation of Ni at different loadings in cerium zirconate inorganic complex structures is investigated in this work as strategy to develop robust Ni-based DRM catalysts.XRD and TPR-H2analyses confirmed the existence of different phases according to the Ni loading in these materials.Besides,superficial Ni is observed as well as the existence of a CeNiO_(3)perovskite structure.The catalytic activity was tested,proving that 10 wt.%Ni loading is the optimum which maximises conversion.This catalyst was also tested in long-term stability experiments at 600and 800℃in order to study the potential deactivation issues at two different temperatures.At 600℃,carbon formation is the main cause of catalytic deactivation,whereas a robust stability is shown at 800℃,observing no sintering of the active phase evidencing the success of this strategy rendering a new family of economically appealing CO_(2)and biogas mixtures upgrading catalysts.
基金supported by the National Natural Science Foundation of China(21576046)the Innovation Team Support Program in Key Areas of the Dalian Science and Technology Bureau(2019RT10).
文摘Coal pyrolysis integrated with dry reforming of low-carbon alkane(CP-DRA)is an effective way to improve tar yield.Ni/La_(2)O_(3)-ZrO_(2) with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition and obtain high tar yield in CP-DRA.In this study,the fraction distribution and component of tars from CP-DRA and coal pyrolysis in N_(2) atmosphere(CP-N_(2))were characterized by using several methods to understand the effect of DRA on coal pyrolysis.The isotope trace method was also used to discuss the role of low-carbon alkane in CP-DRA.The results showed that the tar from CP-N_(2)is mainly composed of aliphatic compounds with more C_(al),H_(al) and CH+CH_(2),and the tar from CP-DRA contains more Car,Har,and CH_(3),and has lower weight-average molecular weight and more light tar content than CP-N_(2).A small amount of C_(2)H_(6) addition in CP-DRA will raise the ratio of H_(β) and CH+CH_(2).Electron paramagnetic resonance(EPR)analysis shows that the tar from CP-DRA has a higher radical concentration while the corresponding char has a lower radical concentration.The isotope trace experiment showed that alkanes provide·H,·CH_(3),etc.to stabilize the radicals from coal pyrolysis and result in more alkyl aromatic compounds during CP-DRA.
文摘An energy production system consisting of a solar collector, biogas dry reforming reactor and solid oxide fuel cell (SOFC) was assumed to be installed in Kolkata, India. This study aims to understand the impact of climate conditions on the performance of solar collectors with different lengths of parabolic trough solar collector (dx) and mass flow rate of heat transfer fluid (m). In addition, this study has evaluated the amount of H2 produced by biogas dry reforming (GH2), the amount of power generated by SOFC (PSOFC) and the maximum number of possible households (N) whose electricity demand could be met by the energy system proposed, considering the performance of solar collector with the different dx and m. As a result, the optimum dx was found to be 4 m. This study revealed that the temperature of heat transfer fluid (Tfb) decreased with the increase in m. Tfb in March, April and May was higher than that in other months, while Tfb from June to December was the lowest. GH2, PSOFC and N in March, April and May were higher than those in other months, irrespective of m. The optimum m was 0.030 kg/s.
基金financially supported by the Joint Fund of Coal, set up by National Natural Science Foundation of China and Shenhua Co., Ltd.(U1261104)the National Natural Science Foundation of China (21276041)+3 种基金the Program for New Century Excellent Talents in University (NCET-12-0079)the Natural Science Foundation of Liaoning Province (2015020200)the Fundamental Research Funds for the Central Universities (DUT15LK41)the Science and Technology Development Program of Hangzhou (20130533B14)~~
文摘An immature pinecone shaped hierarchically structured zirconia （ZrO2-ipch） and a cobblestone-like zirconia nanoparticulate （ZrO2-cs）, both with the monoclinic phase （m-phase）, were synthesized by the facile hydrothermal method and used as the support for a Ni catalyst for the dry reforming of methane （DRM） with CO2. ZrO2-ipch is a much better support than ZrO2-cs and the traditional ZrO2 irregular particles made by a simple precipitation method （ZrO2-ip）. The supported Ni catalyst on ZrO2-ipch （Ni/ZrO2-ipch） exhibited outstanding catalytic activity and coke-resistant stability compared to the ones on ZrO2-cs （Ni/ZrO2-cs） and ZrO2-ip （Ni/ZrO2-ip）. Ni/ZrO2-ip exhibited the worst catalytic performance. The origin of the significantly enhanced catalytic performance was revealed by characterization including XRD, N2 adsorption measurement （BET）, TEM, H2-TPR, CO chemisorption, CO2-TPD, XPS and TGA. The superior catalytic activity of Ni/ZrO2-ipch to Ni/ZrO2-cs or Ni/ZrO2-ip was ascribed to a higher Ni dispersion, increased reducibility, enhanced oxygen mo- bility, and more basic sites with a higher strength, which were due to the unique hierarchically structural morphology of the ZrO2-ipch support. Ni/ZrO2-ipch exhibited better stability for the DRM reaction than Ni/ZrO2-ip, which was ascribed to its higher resistance to Ni sintering due to a strengthened metal-support interaction and the confinement effect of the mesopores and coke deposition resistance. The higher coking resistance of Ni/ZrO2-ipch for the DRM reaction in comparison with Ni/ZrOz-ip orignated from the coke-removalabitity of the higher amount of lattice oxygen and more basic sites, confirmed by XPS and CO2-TPD analysis, and the stabilized Ni on the Ni/ZrO2-ipch catalyst by the confinement effect of the mesopores of the hierarchical ZrO2-ipch sup- port. The superior catalytic performance and coking resistance of the Ni/ZrO2-ipch catalyst makes it a promising candidate for synthesis gas production from the DRM reaction.
