Design And Application Of Highly Efficient Catalysts Based On The Electronic Metal-Support Interaction

Catalysis is an important technology and plays an essential role in our daily lives.It has been reported that more than 90%of chemical manufacturing is based or highly dependent on catalytic processes.The nanomaterial-based catalysts have gained considerable attention,owing to their exposed abundant active sites.However,during storage and reaction,the thermodynamically unstable which originates from the nanoscale morphology can easily induce the aggregation of the nanomaterials,weakening the reactivities.The supported catalyst with efficiently protected active centers has recently emerged as a new research frontier in various catalytic reactions due to its good catalytic activity,superior stability,and easy recovery property.There are many factors influencing the catalytic performance of supported catalysts,such as the support,metal loading,component ratio,and surface morphology.Among them,the electronic metal-support interaction（EMSI）which acts as a bridge between the theoretical electronic study and the design of heterogeneous catalysts,has aroused general attention and wide interest.It can not only stabilize the metal nanoparticles against sintering and leaching,but also regulate the electronic structure of the supported metals improving their catalytic activity and selectivity.Since the structural and synergetic promotion,utilizing the EMSI between the metal and support became one of the most useful strategies to improve the catalytic efficiency.This dissertation mainly focuses on the design of catalysts based on the EMSI effect and investigates their applications in catalytic advanced oxidation processes（AOPs）and electrocatalytic N2reduction reaction（NRR）.1.An atomically dispersing metal-atoms alloy made by guest Au atoms substitute host V atoms in the two-dimensional（2D）VO₂（B）nanobelt support（Au/VO₂）to activate Fenton-like oxidation for the elimination of recalcitrant organic pollutants（ROPs）.The 2D structure enhances the exposure rate of atomically Au,thereby increasing the number of active sites that absorb more S₂O₈^2-ions.Additionally,the EMSI modulates the charge density in Au atoms to present a charge accumulation area weakening the energy barrier for sulfate radicals(SO₄^·-)desorption.The Au/VO₂catalyst exhibits impressive catalytic performance with TOFs as high as 21.42 min^-1,16.19 min^-1,and 80.89 min^-1 for rhodamine（Rh B）,phenol,and bisphenol A（BPA）,respectively.2.Since the EMSI effect can effectively regulate the electrons around the supported metals,it is easy to form electron-rich regions,facilitating the electron transfer.Herein the EMSI was used to adjust the electronic structure of ferric iron（Fe（III））in the VO₂ support to enhance the catalytic activity.The EMSI promotes the electrons on Fe（III）3d-bond center moving close to the Fermi level,promoting the charge transfer from Fe（III）to the adsorbate.The activated Fe（III）can react with peroxydisulfate（PDS）to produce both radicals and high-valent iron（HVFe）,simultaneously.Through the control experiments,both the radical path by PDS and the HVFe path aroused by the EMSI are confirmed for the degradation of ROPs.The Fe/VO₂ catalyst exhibits record-breaking catalytic efficiency with the kinetic model（k-value）as high as 56.7 and 43.3μmol s^-1 g^-1 for p-chlorophenol（4-CP）and 2,4-Dichlorophenol（2,4-DCP）degradation,respectively.The cognition of the EMSI tuning the 3d states of metal atoms to dramatically enhance the catalytic efficiency sheds light on the design of high-efficient catalysts.3.The electrocatalytic N₂ reduction reaction（NRR）is a promising catalytic system for nitrogen fixation under room temperature and ambient pressure.However,most electrocatalysts for NRR suffer from low yield and poor selectivity,hindering their practical applications.Theoretically,the supported catalyst consisting of a metal phase with high NRR activity and support with a stronger adsorption capacity of nitrogen than the proton is easy to achieve the multi-step NRR processes via the formed synergistic effect.In addition,the electronic structure of the supported metal can be tailored to form the electronic defective area by the EMSI raised from the supported metal and support,promoting the activation of nitrogen molecules,which is expected to reduce the energy barrier of the first hydrogenation step and improve the catalytic activity and selectivity of the catalyst.Based on the above assumptions,an excellent NRR catalyst was successfully prepared by loading molybdenum metal（Mo）with high NRR activity on the two-dimensional VO₂ carrier（Mo/VO₂）with a better affinity with nitrogen molecules.At-0.5 V vs RHE the corresponded average NH₃ yield rate reached as high as 190.1μg mg cat.^-1 h^-1 and Faradaic efficiency reached up to 32.4%（0.05 M H₂SO₄）.This work provides a promising generalizable path for the design and synthesis of efficient catalysts for NRR and other multistep catalytic reactions.4.Au-based materials have received extensive attention in electrocatalytic nitrogen fixation due to their low required potential,but their NRR activity remains to be improved due to their weak nitrogen and proton affinity.Inspired by the third work,whereby the support can provide the nitrogen source to the active metallic phase,we describe here an approach to load Au with typical weak NRR activity on a two-dimensional VO₂ carrier（Au/VO₂）,improving the catalytic efficiency of NRR.Additionally,the generated EMSI between Au and VO₂ regulates the charge density in Au atoms to present electron enriched area,facilitating the charge transfer of Au and improving its NRR catalytic activity.The Au/VO₂ electrocatalyst exhibits impressive NRR catalytic performance.At-0.3 V vs RHE,the average NH₃ yield rate of 85.03μg h^-1 mg_cat.^-1and Faradaic efficiency of 19.%（0.5 M H₂SO₄）.This work provides a novel strategy to promote the performance of the NRR catalysts.