Study On The Preparation And Performance Of Non-noble Metal Oxygen Reduction Catalysts

The large consumption of fossil fuels and the serious deterioration of the ecological environment have stimulated the development,utilization and research of clean energy.Due to the high energy density of fuel cells and its advantages of cleanness and environmental benign,many researchers have become interested in the object.However,the development of fuel cells faces many challenges,especially the high price.Fuel cell catalysts account for 56% of the price,hindering the wide commercial development of fuel cells.Today,most of the cathode oxygen reduction(ORR)catalysts for fuel cells use Pt / C catalysts,while the cost of the precious metal Pt is relatively high and less energy is stored in the earth's crust.The development of non-precious metal heteroatom-doped carbon materials as catalysts for oxygen reduction reactions has become the focus of our research.The doping methods,functions and diversity of catalysts have attracted most researchers.Aiming at this series of problems of fuel cells,a cathodic oxygen reduction reaction catalyst is designed and prepared in this paper.A suitable precursor was studied and selected for the synthesis of heteroatom co-doped carbon,which achieved good performance and improved the stability of the catalyst.At the same time,costs were reduced,environmental protection was promoted,and waste utilization was achieved.The main tasks are:A polymerizable ionic liquid was synthesized using phosphoric acid and vinylimidazole as raw materials.The co-doping of nitrogen and phosphorus produced by the polymerizable ionic liquid(PIL)was studied as a precursor for the oxygen reduction reaction catalyst.IL is functionalized with H2PO4-anion,which provides a P heteroatom in the final carbon.At the same time,the cation of IL has nitrogen in its structure,which causes nitrogen heteroatoms to dope the carbon skeleton.Therefore,N-P co-doped carbon materials can be prepared by one-pot method using PIL as a precursor.The composition of carbon makes it a potential metal-free electrocatalyst for ORR.As expected,in tests of alkaline solutions,NP co-doped carbon(C1)compared to only N-doped carbon(C2)and also derived from the non-polymerizable ionic liquid NP co-doped carbon(C3)versus ORR Showed better catalytic activity.The starting potential of C1 reaches 0.93 V and the half-wave potential is 0.75 V,which is very close to the commercial Pt / C catalyst.Its ORR stability also maintained about 90% of the initial current value after 3600 s,and the stability of OER and HER maintained about 60% of the initial current value after 3600 s,indicating that the catalyst also exhibited resistance to OER and HER Catalytic activity.A pine needle biomaterial is used as a precursor to synthesize a fuel cell oxygen reduction catalyst.The properties of calcined carbon material catalysts at different temperatures were explored.The material calcined at high temperature is highly graphitized and uniformly doped with different heteroatoms.The catalyst shows high catalytic activity.Studies have shown that the calcined sample(PN-900)has the best catalytic performance at 900 ?,and its initial potential is about 0.95 V,which is also close to the commercial Pt / C catalyst.Its ORR stability also maintained an initial current value of about 88% after 3600 s.This work eliminates the need to synthesize different heteroatom dopings,making the work simple and effective.At the same time,the utilization of waste is realized,which also provides a new idea for the research of biomass materials.