Converting waste plastics directly into valuable aromatic chemicals is a promising,cost-effective recycling strategy.Traditional zeolite-catalyzed cracking of polyolefins to produce aromatics often needs high temperat...Converting waste plastics directly into valuable aromatic chemicals is a promising,cost-effective recycling strategy.Traditional zeolite-catalyzed cracking of polyolefins to produce aromatics often needs high temperatures and faces issues like low selectivity for liquid aromatics,separation difficulties,and rapid catalyst deactivation due to coking.To address this,a multifunctional Ni/HZSM-5 catalyst was developed to efficiently upgrade various polyolefins—including polyvinyl chloride—into gaseous alkanes(C_(1)–C_(5))and easily separable liquid aromatics(C_(6)–C_(12))at 400°C,without added solvents or hydrogen.Aromatic products make up 57.1 wt%of total output,with more than 97.8%selectivity for the liquid phase and a BTX(benzene,toluene,and xylene)selectivity of 76.1%.The high activity and selectivity for aromatics stem from synergistic interactions between Ni nanoparticles(NPs)and acid sites in the zeolite,which promote selective C–C bond breaking and control hydrogenolysis and aromatization pathways.This synergy allows precise control over the distribution of products by carbon number and favors the formation of separable aromatics.Notably,the catalyst also prevents coking by hydrogenolyzing and hydrogenating reactive intermediates before they form stable graphite-like deposits.Consequently,Ni/ZSM-5 catalyst demonstrates excellent stability,maintaining consistent aromatics yield over 13 consecutive cycles and processing over 30 times its weight in plastics without regeneration.After regeneration,the activity of the catalyst was fully restored,highlighting its potential for industrial use.This work offers valuable insights for designing durable,high-activity catalysts,providing a practical route to improve plastic recycling technologies.展开更多
Cold plasma-assisted catalytic upcycling of polyolefin wastes integrated with CO_(2)into value-added chemicals is a promising solution for mitigating the global carbon emissions and fossil energy crisis,but still chal...Cold plasma-assisted catalytic upcycling of polyolefin wastes integrated with CO_(2)into value-added chemicals is a promising solution for mitigating the global carbon emissions and fossil energy crisis,but still challenging due to the complexity of products and low energy efficiency.Given this,a novel one-stage process of cold plasma coupled with Ga-modified hierarchical H-ZSM-5(Ga/Hie-ZSM-5)catalyst for polyolefins upgrading was designed with polyolefins followed by the catalysts within the plasma region,which facilitated the upcycling of polyolefins to light olefins and CO_(2)activation by plasma,and thereby the enhanced synergy between cold plasma and catalysts for aromatics production.At an input power of ca.45 W without external heating,the low-density polyethylene(LDPE)waste was completely converted with the assistance of CO_(2)and the yield of oil products over the Ga/Hie-ZSM-5 catalyst was highly up to 62.2 wt%,with nearly 100% selectivity of aromatics.Meanwhile,the degradation efficiency of LDPE and the energy efficiency could reach 2.5 g_(LDPE)·g_(cat)^(-1)·h^(-1)and 55.56 g_(LDPE)·g_(cat)^(-1)·kW^(-1)h^(-1),respectively.Mechanism investigation revealed that the plasma and CO_(2)synergistically affect the primary cracking of LDPE,forming a primary product enriched in olefins and a small amount of CO.Subsequently,the produced olefins intermediates were further aromatized via cyclizationdehydrogenation route on the Ga/Hie-ZSM-5 catalyst with assistance of CO_(2)under the synergistic effect of plasma-catalysis.This work offers a feasible strategy to improve the yield of aromatic products for the plasma-catalytic upcycling of polyolefins and CO_(2)at ambient pressure without any external heating.展开更多
The crystallization behavior of two commercial polyolefin elastomer(POE)samples was investigated using the fast scanning chip calorimetry(FSC)technique.Non-isothermal crystallization of the POE samples during cooling ...The crystallization behavior of two commercial polyolefin elastomer(POE)samples was investigated using the fast scanning chip calorimetry(FSC)technique.Non-isothermal crystallization of the POE samples during cooling to low temperatures cannot be inhibited under the largest efficient cooling rate employed in the current work.Thus,the isothermal crystallization of POE samples was limited to a narrow temperature range.When the POE samples were cooled to a certain temperature below the non-isothermal crystallization temperature for crystallization,a crystallization time dependent melting peak appeared in the low temperature region besides the high temperature melting peak originated from the non-isothermal crystallization.This low temperature melting peak was arisen from the melting of crystals isothermally crystallized at the selected crystallization temperature.At each crystallization temperature,the lengths of crystallizable segments were different,thus,the low melting peak increased with increasing the crystallization temperature.In terms of the high melting peak attributed to the non-isothermally crystallized crystals,it somehow decreased with increasing crystallization time and then became constant with further increasing crystallization time at the selected crystallization temperature.This could be explained by the fact that the crystallizable sequences with longer length would nucleate and crystallize first to form thicker crystals during cooling.The subsequent crystallization contributed by the shorter crystallizable sequences will result in the formation of thinner crystals,causing the melting peak to shift to the lower temperature.展开更多
Catalysts are key for olefin polymerization reactions and are also ubiquitous in catalysis science.Multinuclear metal catalysts have witnessed enhanced performances in catalytic reactions relative to mononuclear catal...Catalysts are key for olefin polymerization reactions and are also ubiquitous in catalysis science.Multinuclear metal catalysts have witnessed enhanced performances in catalytic reactions relative to mononuclear catalysts,but which substantially involve multi-step,tedious,and difficult synthesis.Herein,this study reports an intriguing approach to construct multi-nuclear catalysts for the milestoneα-diimine nickel catalysts using an oligomeric strategy.A polymerizable norbornene unit is incorporated into theα-diimine ligand backbone,leading to the formation of the monomeric nickel catalyst Ni_(1)and its corresponding oligomeric nickel catalysts(Ni_(3)and Ni_(5))with varying degrees of polymerization(DP=3 and 5).Notably,the oligomeric catalyst Ni_(5)was facilely scaled up(50 g-level),showed enhanced thermal stability,exhibited 4.6 times higher activity,and yielded polyethylene elastomer with a 379%increased molecular weight in ethylene polymerization,compared to the monomeric catalyst Ni_(1).Catalytic performance enhancements of oligomeric catalysts were found to be DP-dependent.The kilogram-scale polyethylene,produced using Ni_(5)in a 20 L reactor,presented a highly branched all-hydrocarbon structure,which demonstrated typical elastic properties(tensile strength:4 MPa,elastic recovery:SR=72%)along with great processability(MFI=3.0 g/10 min),insulating characteristics(volume resistivity=2×10^(16)Ω/m),and hydrophobicity(water vapor permeability:0.03 g/m^(2)/day),suggesting potentially practical applications.展开更多
As a long-term project aimed at developing super polyolefin blends, in this paper we summarize our work on themechanical reinforcement and phase morphology of polyolefin blends achieved by dynamic packing injection mo...As a long-term project aimed at developing super polyolefin blends, in this paper we summarize our work on themechanical reinforcement and phase morphology of polyolefin blends achieved by dynamic packing injection molding(DPIM). The main feature of this technology is that the specimen is forced to move repeatedly in the model by two pistonsthat move reversibly with the same frequency during cooling, which results in preferential orientation of the dispersed phaseas well as the matrix. The typical morphology of samples obtained via DPIM is a shear-induced morphology with a core inthe center, an oriented zone surrounding the core and a skin layer in the cross-section areas. Shear-induced phase dissolutionat a higher shear rate but phase separation at low shear rates is evident from AFM examination of LLDPE/PP (50/50) blends.The super polyolefin blends having high modulus (1.9-2.2 GPa), high tensile strength (100-120 MPa) and high impactstrength (6 times as that of pure HDPE) have been prepared by controlling the phase separation, molecular orientation andcrystal morphology.展开更多
As an important part of semicrystalline polymer materials,polyolefin elastomers are widely used,and the in-depth analysis of their molecular chain structure information is of great significance to promote their rapid ...As an important part of semicrystalline polymer materials,polyolefin elastomers are widely used,and the in-depth analysis of their molecular chain structure information is of great significance to promote their rapid development.We show in this work an effort in characterizing a commercial polyolefin elastomer of ethylene/1-octene copolymer by a modified successive self-nucleation and annealing(SSA)technique.A small amount of linear polyethylene was blended with the ethylene/1-octene copolymer serving as nucleation agent during SSA.It turned out that a tiny fraction of linear polyethylene can significantly promote the crystallization of the copolymer during cooling from different annealing temperatures and increase the melting temperature of the fractions so that providing apparent methylene sequence length much closer to the real value than obtained by traditional SSA technique.展开更多
Serratia marcescens strain 9986 is a producer of prodigiosin used as a dye of polyolefines (polyethylene, ultratene). The biosynthesis of pigment was closely connected with controlled growth parameters. A prodigiosin ...Serratia marcescens strain 9986 is a producer of prodigiosin used as a dye of polyolefines (polyethylene, ultratene). The biosynthesis of pigment was closely connected with controlled growth parameters. A prodigiosin yield 0.2 - 0.4 mg per l of culture medium in the batch culture under aerobic conditions was obtained. Prodigiosin was extracted from crude biomass treated by 0.1% of sodium dodecyl sulfate (SDS). This novel elaborated stage is necessary for thermostability a dye in polymer. The consumption of prodigiosin preparation is more economical in the technology of the coloration of polyolefines. The elaborated method has been manufactured for dyeing polyethylene by biological pigment-articles of the common use corresponding to the technological standard.展开更多
The morphology and properties of HDPE blends with Zn-SEPDM and GR were studied through SEM and mechanical property test. The results show that as Zn-SEPDM/GR content amounts to 20%, the blend becomes an IPN in structu...The morphology and properties of HDPE blends with Zn-SEPDM and GR were studied through SEM and mechanical property test. The results show that as Zn-SEPDM/GR content amounts to 20%, the blend becomes an IPN in structure, and that a rather high impact and tensile strength of HDPE may be obtained after blending. The antistatic effect, the softening point,and HDT of the blend are higher as compared to HDPE/Zn-SEPDM/ZnSt (zinc stearate).The effect of Zn-SEPDM on the compatibility the morphology and properties of IPP blends were studied by DSC, TEM and mechanical properties test. The results show that as Zn-SEPDM content exceeds 20%. Zn-SEPDM in the blend becomes continuous and an abrupt change in impact strength is incurred there from. Owing to the incorporation of ionic groups into EPDM.the strong interactions betWeen the chains make both the impact and the tensile strength of IPP remarkably higher展开更多
The diffusion coefficient of volatiles in polymer solutions is a crucial parameter to describe the mass transfer efficiency and ability of volatiles.In this research,polyolefin elastomer(POE)was used as a polymer,and ...The diffusion coefficient of volatiles in polymer solutions is a crucial parameter to describe the mass transfer efficiency and ability of volatiles.In this research,polyolefin elastomer(POE)was used as a polymer,and cyclohexane was used as a volatile.A gravimetric analysis was applied to measure the diffusion coefficient of cyclohexane in POE.The devolatilization rate of the POE-cyclohexane system under different conditions was measured.The effects of temperature,film sample thickness,and initial concentration of volatiles on the devolatilization rate were discussed.Based on the devolatilization rate data,the average diffusion coefficient of cyclohexane in POE was obtained by fitting with a mathematical model.The experimental results indicate that the devolatilization rate increased with increasing temperature and initial concentration of volatiles,but it decreased with increasing sample thickness.As the thickness increased,the overall diffusion resistance increased.As the temperature increased,the molecular movement increased,resulting in the increase of average diffusion coefficient.The relationship between the diffusion coefficient of the POE-cyclohexane system and temperature follows the Arrhenius law.The diffusion activation energy E=6201.73 J/mol,and the pre-exponential factor of the diffusion coefficient D0=2.64×10^(-10) m^(2)/s.This work can provide basic data for exploring the devolatilization of POE polymers and serves as a useful reference for enhancing the effect of devolatilization.展开更多
The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C b...The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C bonds in mixed polyolefin plastics over non-noble metal catalysts under mild conditions. The nickelbased catalyst involving Ni_(2)Al_(3) phase enables the direct transformation of mixed polyolefin plastics into natural gas, and the gas carbon yield reaches up to 89.6%. Reaction pathway investigation reveals that natural gas comes from the stepwise catalytic cleavage of C–C bonds in polypropylene, and the catalyst prefers catalytic cleavage of terminal C–C bond in the side-chain with the low energy barrier.Additionally, our developed approach is evaluated by the technical economic analysis for an economically competitive production process.展开更多
基金supported by the National Key R&D Program of China(2021YFA1501700)the National Natural Science Foundation of China(22272114)+2 种基金the Funding for Hundred Talent Program(20822041E4079)the Fundamental Research Funds from Sichuan University(2022SCUNL103)This work has also been supported by SINOPEC Research Institute of Petroleum Processing Co.,Ltd.via collaborative project No.36800000-24-ZC0607-0175.
文摘Converting waste plastics directly into valuable aromatic chemicals is a promising,cost-effective recycling strategy.Traditional zeolite-catalyzed cracking of polyolefins to produce aromatics often needs high temperatures and faces issues like low selectivity for liquid aromatics,separation difficulties,and rapid catalyst deactivation due to coking.To address this,a multifunctional Ni/HZSM-5 catalyst was developed to efficiently upgrade various polyolefins—including polyvinyl chloride—into gaseous alkanes(C_(1)–C_(5))and easily separable liquid aromatics(C_(6)–C_(12))at 400°C,without added solvents or hydrogen.Aromatic products make up 57.1 wt%of total output,with more than 97.8%selectivity for the liquid phase and a BTX(benzene,toluene,and xylene)selectivity of 76.1%.The high activity and selectivity for aromatics stem from synergistic interactions between Ni nanoparticles(NPs)and acid sites in the zeolite,which promote selective C–C bond breaking and control hydrogenolysis and aromatization pathways.This synergy allows precise control over the distribution of products by carbon number and favors the formation of separable aromatics.Notably,the catalyst also prevents coking by hydrogenolyzing and hydrogenating reactive intermediates before they form stable graphite-like deposits.Consequently,Ni/ZSM-5 catalyst demonstrates excellent stability,maintaining consistent aromatics yield over 13 consecutive cycles and processing over 30 times its weight in plastics without regeneration.After regeneration,the activity of the catalyst was fully restored,highlighting its potential for industrial use.This work offers valuable insights for designing durable,high-activity catalysts,providing a practical route to improve plastic recycling technologies.
基金financially supported by the National Key R&D Program of China(2023YFA1506602 and 2021YFA1501102)the National Natural Science Foundation of China(21932002,22276023,22402019)+1 种基金the Fundamental Research Funds for the Central Universities(DUT22LAB602)Liaoning Binhai Laboratory Project(LBLF-202306)。
文摘Cold plasma-assisted catalytic upcycling of polyolefin wastes integrated with CO_(2)into value-added chemicals is a promising solution for mitigating the global carbon emissions and fossil energy crisis,but still challenging due to the complexity of products and low energy efficiency.Given this,a novel one-stage process of cold plasma coupled with Ga-modified hierarchical H-ZSM-5(Ga/Hie-ZSM-5)catalyst for polyolefins upgrading was designed with polyolefins followed by the catalysts within the plasma region,which facilitated the upcycling of polyolefins to light olefins and CO_(2)activation by plasma,and thereby the enhanced synergy between cold plasma and catalysts for aromatics production.At an input power of ca.45 W without external heating,the low-density polyethylene(LDPE)waste was completely converted with the assistance of CO_(2)and the yield of oil products over the Ga/Hie-ZSM-5 catalyst was highly up to 62.2 wt%,with nearly 100% selectivity of aromatics.Meanwhile,the degradation efficiency of LDPE and the energy efficiency could reach 2.5 g_(LDPE)·g_(cat)^(-1)·h^(-1)and 55.56 g_(LDPE)·g_(cat)^(-1)·kW^(-1)h^(-1),respectively.Mechanism investigation revealed that the plasma and CO_(2)synergistically affect the primary cracking of LDPE,forming a primary product enriched in olefins and a small amount of CO.Subsequently,the produced olefins intermediates were further aromatized via cyclizationdehydrogenation route on the Ga/Hie-ZSM-5 catalyst with assistance of CO_(2)under the synergistic effect of plasma-catalysis.This work offers a feasible strategy to improve the yield of aromatic products for the plasma-catalytic upcycling of polyolefins and CO_(2)at ambient pressure without any external heating.
基金financially supported by the National Natural Science Foundation of China(No.52422301)Natural Science Foundation of Jilin Province(No.SKL202302033)。
文摘The crystallization behavior of two commercial polyolefin elastomer(POE)samples was investigated using the fast scanning chip calorimetry(FSC)technique.Non-isothermal crystallization of the POE samples during cooling to low temperatures cannot be inhibited under the largest efficient cooling rate employed in the current work.Thus,the isothermal crystallization of POE samples was limited to a narrow temperature range.When the POE samples were cooled to a certain temperature below the non-isothermal crystallization temperature for crystallization,a crystallization time dependent melting peak appeared in the low temperature region besides the high temperature melting peak originated from the non-isothermal crystallization.This low temperature melting peak was arisen from the melting of crystals isothermally crystallized at the selected crystallization temperature.At each crystallization temperature,the lengths of crystallizable segments were different,thus,the low melting peak increased with increasing the crystallization temperature.In terms of the high melting peak attributed to the non-isothermally crystallized crystals,it somehow decreased with increasing crystallization time and then became constant with further increasing crystallization time at the selected crystallization temperature.This could be explained by the fact that the crystallizable sequences with longer length would nucleate and crystallize first to form thicker crystals during cooling.The subsequent crystallization contributed by the shorter crystallizable sequences will result in the formation of thinner crystals,causing the melting peak to shift to the lower temperature.
基金financial support from the National Natural Science Foundation of China(Nos.22401274,U23B6011)the Jilin Provincial Science and Technology Department Program(No.20250102070JC)。
文摘Catalysts are key for olefin polymerization reactions and are also ubiquitous in catalysis science.Multinuclear metal catalysts have witnessed enhanced performances in catalytic reactions relative to mononuclear catalysts,but which substantially involve multi-step,tedious,and difficult synthesis.Herein,this study reports an intriguing approach to construct multi-nuclear catalysts for the milestoneα-diimine nickel catalysts using an oligomeric strategy.A polymerizable norbornene unit is incorporated into theα-diimine ligand backbone,leading to the formation of the monomeric nickel catalyst Ni_(1)and its corresponding oligomeric nickel catalysts(Ni_(3)and Ni_(5))with varying degrees of polymerization(DP=3 and 5).Notably,the oligomeric catalyst Ni_(5)was facilely scaled up(50 g-level),showed enhanced thermal stability,exhibited 4.6 times higher activity,and yielded polyethylene elastomer with a 379%increased molecular weight in ethylene polymerization,compared to the monomeric catalyst Ni_(1).Catalytic performance enhancements of oligomeric catalysts were found to be DP-dependent.The kilogram-scale polyethylene,produced using Ni_(5)in a 20 L reactor,presented a highly branched all-hydrocarbon structure,which demonstrated typical elastic properties(tensile strength:4 MPa,elastic recovery:SR=72%)along with great processability(MFI=3.0 g/10 min),insulating characteristics(volume resistivity=2×10^(16)Ω/m),and hydrophobicity(water vapor permeability:0.03 g/m^(2)/day),suggesting potentially practical applications.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29992535) and the China National Distinguished Young Investigator Fund.
文摘As a long-term project aimed at developing super polyolefin blends, in this paper we summarize our work on themechanical reinforcement and phase morphology of polyolefin blends achieved by dynamic packing injection molding(DPIM). The main feature of this technology is that the specimen is forced to move repeatedly in the model by two pistonsthat move reversibly with the same frequency during cooling, which results in preferential orientation of the dispersed phaseas well as the matrix. The typical morphology of samples obtained via DPIM is a shear-induced morphology with a core inthe center, an oriented zone surrounding the core and a skin layer in the cross-section areas. Shear-induced phase dissolutionat a higher shear rate but phase separation at low shear rates is evident from AFM examination of LLDPE/PP (50/50) blends.The super polyolefin blends having high modulus (1.9-2.2 GPa), high tensile strength (100-120 MPa) and high impactstrength (6 times as that of pure HDPE) have been prepared by controlling the phase separation, molecular orientation andcrystal morphology.
基金financially supported by the National Natural Science Foundation of China Enterprise Innovation and Development Joint Fund(No.U19B6001)。
文摘As an important part of semicrystalline polymer materials,polyolefin elastomers are widely used,and the in-depth analysis of their molecular chain structure information is of great significance to promote their rapid development.We show in this work an effort in characterizing a commercial polyolefin elastomer of ethylene/1-octene copolymer by a modified successive self-nucleation and annealing(SSA)technique.A small amount of linear polyethylene was blended with the ethylene/1-octene copolymer serving as nucleation agent during SSA.It turned out that a tiny fraction of linear polyethylene can significantly promote the crystallization of the copolymer during cooling from different annealing temperatures and increase the melting temperature of the fractions so that providing apparent methylene sequence length much closer to the real value than obtained by traditional SSA technique.
文摘Serratia marcescens strain 9986 is a producer of prodigiosin used as a dye of polyolefines (polyethylene, ultratene). The biosynthesis of pigment was closely connected with controlled growth parameters. A prodigiosin yield 0.2 - 0.4 mg per l of culture medium in the batch culture under aerobic conditions was obtained. Prodigiosin was extracted from crude biomass treated by 0.1% of sodium dodecyl sulfate (SDS). This novel elaborated stage is necessary for thermostability a dye in polymer. The consumption of prodigiosin preparation is more economical in the technology of the coloration of polyolefines. The elaborated method has been manufactured for dyeing polyethylene by biological pigment-articles of the common use corresponding to the technological standard.
文摘The morphology and properties of HDPE blends with Zn-SEPDM and GR were studied through SEM and mechanical property test. The results show that as Zn-SEPDM/GR content amounts to 20%, the blend becomes an IPN in structure, and that a rather high impact and tensile strength of HDPE may be obtained after blending. The antistatic effect, the softening point,and HDT of the blend are higher as compared to HDPE/Zn-SEPDM/ZnSt (zinc stearate).The effect of Zn-SEPDM on the compatibility the morphology and properties of IPP blends were studied by DSC, TEM and mechanical properties test. The results show that as Zn-SEPDM content exceeds 20%. Zn-SEPDM in the blend becomes continuous and an abrupt change in impact strength is incurred there from. Owing to the incorporation of ionic groups into EPDM.the strong interactions betWeen the chains make both the impact and the tensile strength of IPP remarkably higher
基金The authors wish to express their thanks for the financial support from the Polyolefin Elastomer Technology Development project(2020B-2619).
文摘The diffusion coefficient of volatiles in polymer solutions is a crucial parameter to describe the mass transfer efficiency and ability of volatiles.In this research,polyolefin elastomer(POE)was used as a polymer,and cyclohexane was used as a volatile.A gravimetric analysis was applied to measure the diffusion coefficient of cyclohexane in POE.The devolatilization rate of the POE-cyclohexane system under different conditions was measured.The effects of temperature,film sample thickness,and initial concentration of volatiles on the devolatilization rate were discussed.Based on the devolatilization rate data,the average diffusion coefficient of cyclohexane in POE was obtained by fitting with a mathematical model.The experimental results indicate that the devolatilization rate increased with increasing temperature and initial concentration of volatiles,but it decreased with increasing sample thickness.As the thickness increased,the overall diffusion resistance increased.As the temperature increased,the molecular movement increased,resulting in the increase of average diffusion coefficient.The relationship between the diffusion coefficient of the POE-cyclohexane system and temperature follows the Arrhenius law.The diffusion activation energy E=6201.73 J/mol,and the pre-exponential factor of the diffusion coefficient D0=2.64×10^(-10) m^(2)/s.This work can provide basic data for exploring the devolatilization of POE polymers and serves as a useful reference for enhancing the effect of devolatilization.
基金supported by the National Natural Science Foundation of China (grant 22208339)the China Postdoctoral Science Foundation (2021M693132)+2 种基金the National Key R&D Program of China (2019YFC1905303)the Doctoral Scientific Research Foundation of Liaoning Province (2021-BS-006)the Youth Innovation Fund of Dalian Institute of Chemical Physics (DICP I202132)。
文摘The inert carbon–carbon(C–C) bonds cleavage is a main bottleneck in the chemical upcycling of recalcitrant polyolefin plastics waste. Here we develop an efficient strategy to catalyze the complete cleavage of C–C bonds in mixed polyolefin plastics over non-noble metal catalysts under mild conditions. The nickelbased catalyst involving Ni_(2)Al_(3) phase enables the direct transformation of mixed polyolefin plastics into natural gas, and the gas carbon yield reaches up to 89.6%. Reaction pathway investigation reveals that natural gas comes from the stepwise catalytic cleavage of C–C bonds in polypropylene, and the catalyst prefers catalytic cleavage of terminal C–C bond in the side-chain with the low energy barrier.Additionally, our developed approach is evaluated by the technical economic analysis for an economically competitive production process.
