Synthesis And Application Of Biomass-derived Porous Carbon-based Nanocomposite Catalysts

Changes in energy structure are closely related to people’s lives.In recent years,environmental pollution problems caused by the heavy use of fossil fuels and the global energy crisis have received much attention.As a typical source of organic dye pollution in wastewater,we should attach great importance to its handling.In terms of energy storage,scholars continue to explore new energy storage devices such as fuel cells,metal air cells and total hydrolysis reactors in an attempt to replace the use of traditional fossil fuels.Among them,the more critical technologies are oxygen reduction reaction(ORR),oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).The commonly used noble metal electrochemical catalysts Pt,Ru and Ir are not only costly,but also cannot guarantee high catalytic performance and high catalytic stability in the catalytic process.Therefore,developing an efficient,durable and low-cost multi-functional catalyst that can degrades and catalyzes an electrochemic reaction of p-nitrophenol is highly desirable.In this paper,the preparation process of biomass-derived porous carbon-based nanocomposite catalyst with controllable morphology by using freshly picked holly leaves as raw material and cobalt nitrate as precursor is described.The new structure(Yolk-Shell)was verified by XRD,TEM,HRTEM,XPS,EDS and other conventional characterization methods.The formation mechanism and reaction performance of Yolk-Shell structure were inferred by controlled experiments.The electrochemical test results show that the synthesized Yolk-Shell Co-CoO/BC exhibits excellent ORR performance superior to Solid Co-CoO/BC and similar to commercial platinum,with a half-wave potential of 0.82 V and a starting potential of 0.91 V(vs.RHE),and the catalytic process path is a an effective 4e" transfer process.In addition,a low potential of η10=1.77 V is exhibited during the total hydrolysis,and the catalytic performance is superior to that of the noble metal commercial platinum.In addition,the phosphating of Yolk-Shell Co-CoO/BC was carried out by traditional calcination phosphating method and low temperature molten salt phosphating method,respectively,CoP/BC-T and CoP/BC-MS nanosphere catalysts were successfully prepared.Qualitative and quantitative analysis of the morphology and composition of the materials by XRD,TEM,HRTEM,XPS,EDS and other related characterization methods.The electrochemical test results show that the synthesized HER performance of CoP/BC-T is better than that of CoP/BC-MS and Yolk-Shell Co-CoO/BC,which is similar to commercial platinum carbon.At a current density of 10 mA·cm-2,the potentials of CoP/BC-T,CoP/BC-MS,and Yolk-Shell Co-CoO/BC were 0.07 V,0.14 V,and 0.23 V.In other words,the introduction of phosphorus helps to enhance the HER activity and stability of the material.In addition,the 4-NP hydrogenation of the synthesized catalysts was studied(Co-CoO/BC,CoP/BC).The test results showed that the hollow structure of CoP/BC-T and Yolk-Shell Co-CoO/BC had better performance,and the whole catalytic process was completed in 3.5 min and 7.0 min.After 5 cycles,the conversion rates remained at 90.1%and 87.5%,respectively,with excellent 4-NP hydrogenation activity and stability.The synthesis method used in this paper is simple and low-cost.The high catalytic activity and stability catalyst with special structure can be prepared by regulating the preparation of conditional variables,which has certain reference significance for the later synthesis of such special structure catalysts.