Electrocatalytic valorization of disused poly(ethylene terephthalate)(PET)plastics into value-added chemicals emerges as a potential approach to address plastic pollution and resources upgrading,but it faces challenge...Electrocatalytic valorization of disused poly(ethylene terephthalate)(PET)plastics into value-added chemicals emerges as a potential approach to address plastic pollution and resources upgrading,but it faces challenges in the development of efficient catalysts for PET-derived ethylene glycol(EG)electrooxidation.Herein,we proposed pyramid arrays on sheet Fe-doped NiO/FeNi_(3)(SPA-NiFeO_(x)/FeNi_(3))heterostructure,which is derived from the pyrolysis of MOF-on-MOF heterostructure growth triggered by graphene quantum dots(GQDs).Such SPA-NiFeO_(x)/FeNi_(3)exhibits superior catalytic performance on the electrooxidation of EG(EGOR)from PET hydrolysate,with a formic acid(FA)selectivity of 91.5%and a Faradaic efficiency of 92%.The ligand effect of GQDs in both the catalyst design and improved electrocatalytic performance was studied with combined spectroscopy analysis and theoretical calculations,which revealed that such spatially separated NiFeO_(x)and FeNi_(3)components by GQDs possess more active sites to anticipate in electrocatalytic EGOR,and the large sp2 domains in GQDs possess a strong electron-withdrawing ability to reduce the electron density of bonded Ni and Fe,resulting in high-valenced Ni^(δ+)/Fe^(δ+)in FeNi_(3)and Ni(2+δ)in NiO,respectively.Furthermore,the coordination number of Ni and Fe centers was lowered due to the steric effect of GQDs.Therefore,the adsorption of EG on Ni^(δ+)for cascade dehydrogenation and C–C bond cleavage led to adsorbed FA that transferred to adjacent Fe for desorption,which was promoted by the enrichment of OH−on nearby Ni^((2+δ))sites,along with optimized Gibbs free energy change in the multistep reaction pathway.This work provides an efficient multi-active-site catalyst for disused PET plastics valorization,thereby presenting a new approach to enhance the efficiency of PET plastics valorization reactions.展开更多
We present a theoretical study of new nanostructures based on bilayered graphene with periodically arranged hexagonal holes （bilayered graphene antidots）. Our ab initio calculations show that fabrication of hexagona...We present a theoretical study of new nanostructures based on bilayered graphene with periodically arranged hexagonal holes （bilayered graphene antidots）. Our ab initio calculations show that fabrication of hexagonal holes in bigraphene leads to connection of the neighboring edges of the two graphene layers with formation of a hollow carbon nanostructure sheet which displays a wide range of electronic properties （from semiconductor to metallic）, depending on the size of the holes and the distance between them. The results were additionally supported by wave packet dynamical transport calculations based on the numerical solution of the time-dependent Schr/Sdinger equation.展开更多
基金support from the National Natural Science Foundation of China(Grant No.22102140the Natural Science Foundation of Jiangsu Province(Grant No.BK20211602)+1 种基金the Qing Lan Project of Yangzhou Universitythe Postgraduate Research&Practice Innovation Program of Jiangsu Province(Yangzhou University,Grant No.SJCX23_1911).
文摘Electrocatalytic valorization of disused poly(ethylene terephthalate)(PET)plastics into value-added chemicals emerges as a potential approach to address plastic pollution and resources upgrading,but it faces challenges in the development of efficient catalysts for PET-derived ethylene glycol(EG)electrooxidation.Herein,we proposed pyramid arrays on sheet Fe-doped NiO/FeNi_(3)(SPA-NiFeO_(x)/FeNi_(3))heterostructure,which is derived from the pyrolysis of MOF-on-MOF heterostructure growth triggered by graphene quantum dots(GQDs).Such SPA-NiFeO_(x)/FeNi_(3)exhibits superior catalytic performance on the electrooxidation of EG(EGOR)from PET hydrolysate,with a formic acid(FA)selectivity of 91.5%and a Faradaic efficiency of 92%.The ligand effect of GQDs in both the catalyst design and improved electrocatalytic performance was studied with combined spectroscopy analysis and theoretical calculations,which revealed that such spatially separated NiFeO_(x)and FeNi_(3)components by GQDs possess more active sites to anticipate in electrocatalytic EGOR,and the large sp2 domains in GQDs possess a strong electron-withdrawing ability to reduce the electron density of bonded Ni and Fe,resulting in high-valenced Ni^(δ+)/Fe^(δ+)in FeNi_(3)and Ni(2+δ)in NiO,respectively.Furthermore,the coordination number of Ni and Fe centers was lowered due to the steric effect of GQDs.Therefore,the adsorption of EG on Ni^(δ+)for cascade dehydrogenation and C–C bond cleavage led to adsorbed FA that transferred to adjacent Fe for desorption,which was promoted by the enrichment of OH−on nearby Ni^((2+δ))sites,along with optimized Gibbs free energy change in the multistep reaction pathway.This work provides an efficient multi-active-site catalyst for disused PET plastics valorization,thereby presenting a new approach to enhance the efficiency of PET plastics valorization reactions.
文摘We present a theoretical study of new nanostructures based on bilayered graphene with periodically arranged hexagonal holes （bilayered graphene antidots）. Our ab initio calculations show that fabrication of hexagonal holes in bigraphene leads to connection of the neighboring edges of the two graphene layers with formation of a hollow carbon nanostructure sheet which displays a wide range of electronic properties （from semiconductor to metallic）, depending on the size of the holes and the distance between them. The results were additionally supported by wave packet dynamical transport calculations based on the numerical solution of the time-dependent Schr/Sdinger equation.
