The Application Of MDFs And Their Derivatives In Electrocatalysis And Artificial Mimic Enzyme Catalysis

Metal organic frameworks（MOFs）have excellent properties such as ultra-high specific surface area,adjustable pore size,easy-to-modify surface and open active sites,which have been applied in various fields.In order to fully exploit the advantages of MOFs,researchers have paid much attention to the modification and functionalization of MOFs.For example,the carbonized MOFs can not only obtain the metal oxides with strong catalytic activity,but greatly improve the conductivity of MOFs,which can achieve satisfactory results in electrocatalytic applications.Taking the advantages of the porous and rigid structures of MOFs,they can commonly be used as carriers to combine other functional materials with high catalytical activity or high conductance to obtain MOFs-based composites.The composites not only have the superiority to both materials,but can generate new properties owing to the synergistic effect of them,which greatly expands the usage of MOFs in various fields.In this paper,based on the progress of MOFs and their derivatives,several MOFs and their derivatives were prepared and preliminary applied in nanoenzyme catalysis and electrocatalysis.The details are as follows:1.HKUST-1 has been synthesized and proved as an efficient nitrogen reduction reaction（NRR）electrocatalyst for N₂ conversion to NH₃ under ambient conditions.Electrochemical tests revealed that HKUST-1 has a large NH₃ yield rate of 46.63μg h^–11 mg^–1_catat and a high Faradaic efficiency of 2.45%at–0.75 V vs.reversible hydrogen electrode（RHE）in 0.1 M Na₂SO₄.Moreover,HKUST-1 also exhibited high stability,reusability,and excellent selectivity in NRR.This method can conque the disadvantages of the conventional Haber-Bosch process for NH₃ synthesis,which is an energy-intensive and large CO₂-emitting process.The electrocatalytic N₂ reduction as an alternative approach for N₂ fixition can conduct under mild conditions.It opened a new way for MOFs in the application of nitrogen reduction reaction.2.The novel catalyst of FeCo nanoparticles incorporated porous nanocages（FeCo NPs@PNC）was first synthesized by encapsulating FeCo alloy into ZIF-8 and further carbonation in N₂ atmosphere.The FeCo NPs@PNC displays enhanced intrinsic oxidase-like activity compared to the individual FeCo NPs and porous nanocages（PNC）.It can catalyze the oxidation of 3,3’,5,5’-tetramethylbenzidine（TMB）without H₂O₂ to produce a blue color with an absorption maximum at 652nm.But ascorbic acid（AA）can reduce the oxTMB and result in a conspicuous blue color fading.Therefore,a novel colorimetric biosensing platform was constructed to quantify AA in the range of 0.5–28μM with the detection limit of 0.38μM.The alkaline phosphatase（ALP）can catalyze the hydrolysis of AA 2-phosphate（AAP）into AA.For the reason that,ALP also could be quantified by the above method,and the linear range for ALP is 0.6–10 U L^–11 and the detection limit was measured to be0.49 U L^–1.The FeCo NPs@PNC also shows excellent stability and reproducibility.3.Herein,FeCo co-doped carbon sphere（FeCo@C）was obtained from the carbonized of FeCo-ZIF,which have intrinsic oxidase-like and peroxidase-like activity.The unique dual-enzyme catalytic properties of FeCo@C could be simply regulated and utilized as bifunctional colorimetric biosensors.At pH 3.6 and catalytic time with 6 min,FeCo@C possesses strong oxidase-like activity;however,with the pH increased to 4.4 and catalytic reaction time of 3 min,the oxidase-like activity of FeCo@C is obviously weakened,and the peroxidase-like activity still exhibits satisfactory level.Based on the oxidase-like activity of FeCo@C,a novel colorimetric biosensing platform for HQ was constructed with linear range of 1–30μM and detection limit of 0.8μM.And a facile analytical method was developed to detect H₂O₂ based on the peroxidase-like activity,which had linear range of 1–240μM and detection limit of 1μM.And the as-obtained FeCo@C has high stability and recyclability.