Preparation And Electrocatalytic Performance Of Transition Metal And Heteroatom Doped Carbon Materials

Sustainable clean energy conversion technologies,such as fuel cells and water splitting technology,have trigged numerous interests in the worldwide due to the continuous increasing of energy consumption Currently,the best catalysts,such as platinum and ruthenium-based catalysts,are seriously hindered the development of fuel cells and electrochemical water splitting technologies due to their scarcity,high price and poor stability.Therefore,the only way to promote the large-scale application of fuel cell and water splitting technologies is to develop new catalysts with high catalytic activity,stability and low price.Herein,the chemical composition,specific surface area and pore structure of the carbon-based catalysts are controllable tuned by experimental strategy.The Fe,Co,N and P elements are employed to modified the carbon materials.Four types of efficient transition metal and heteroatom doping carbon materials are successfully synthesized and chracterized:First,to prevent the aggregation of the metal nanoparticles and the collapse of the channel under heating,phenanthroline iron complex is adsorbed into the pores of MOFs by site isolation method.Iron and N co-doped hierarchical porous carbon materials?Fe/N/C-T?is obtained by the following pyrolysis at high temperatures.Secondly,CTAC and SiO₂ is used as soft and hard templates respectively to tune the surface area and porosity structure,and then the hierarchically porous carbon spheres?Fe/N-HCS-X-T?with hollow structure is obtained after high-temperature pyrolysis and acid etching.Thirdly,a kind of aniline pentamer were used as ligand to prepare Fe/Co-MOF loading on NF through solvethermal method.Through phosphating,Fe₂P,Co₂P,N and P modified carbon material?Fe/Co/P-NPs?is obtained.Fourth,Co doped prussian blue precursor is prepared on NF by ligand exchange reaction derived from ZIF-67/8.FeP,Fe₂P,Co₂P and P funationalized hill-like carbon catalyst?Fe/Co/P-ZIF-67,8?is obtained by a following phosphating process.Finally,scanning electron microscope?SEM?,transmission electron microscope?TEM?,X-ray photoelectron spectroscopy?XPS?and X-ray diffraction spectroscopy?XRD?are used to characterize the morphology and structure of the materials.The electrocatalytic activity,stability and methanol resistance of the materials are characterized by cyclic voltammetry?CV?,linear sweep voltammetry?LSV?and time-current stability test?I-T?.It is found that Fe/N/C-900 and Fe/N-HCS-0.5-800 have high specific surface area and abundant pore structure.The onset potential of the two materials in alkaline condition for ORR is 0.98 and 1.00 V vs.RHE,respectively,indicating highly efficient ORR catalytic activity.The catalytic performance of Fe/N-HCS-0.5-800 in alkaline condition for ORR is even slightly better than that of Pt/C.In addition,the onset overpotential of Fe/N-HCS-0.5-800 in acidic condition for HER was 40 mV,suggesting excellent catalytic activity.Fe/Co/P-NPs and Fe/Co/P-ZIF-67,8 display a very good OER catalytic activity,with overpotentials of 270 and 220 mV to deliver 10 mA cm^-2,respectively,proving the better activity than that of RuO₂.And they show excellent catalytic activity for HER in acid/alkaline soutions and water splitting reactions.