Titanium Oxide Loaded On Nanometer Boron Carbide As Bifunctional Electrocatalyst

In recent years,many new types of energy storage and conversion technology have been rapid development,among of them fuel cells and water electrolysis technology can form a unitized regenerative fuel cell system.This system can realize the circulation of chemical energy and electrical energy conversion,so the use efficiency of energy is very high.It will play an important role in alleviating the energy crisis and environmental pollution.The oxygen reduction reaction and oxygen evolution reaction simultaneously happened on the oxygen electrode system,so oxygen electrode catalysts should be bifunctional.For traditional bifunctional catalysts,the high cost and short service life have slow down the speed of its development.So the development of efficient bifunctional oxygen electrode catalyst with high stability and low cost is particularly important.In this project,we used nano-B₄C as carrier material,which is high stability.Firstly,nano TiO₂ loaded onto the surface of B₄C?TiO₂/B₄C?by microwave assisted deposition.Under the protection of nitrogen,700°C heat treatment,a core-shell bifunctional catalyst?B-TiO₂/B-C@B₄C-700?have been prepared,which the nano-B₄C as core,surface formed by the B self-doping carbon?B-C?and B-doping TiO₂?B-TiO₂?.The morphology and structure of B-TiO₂/B-C@B₄C-700 be confirmed through XRD,TEM,XPS and other means.The electrochemical test results,which in 0.1MKOH alkaline solution showed that the initial potential of B-TiO₂/B-C@B₄C-700 catalytic for oxygen reduction reaction?ORR?is 0.83V?vs.RHE?,the half-wave potential is 0.73 V.For oxygen evolution reaction?OER?,the 10mA/cm² current density value corresponding to the oxygen evolution over potential value is 1.56 V.Then TiO₂/B₄C and melamine be mixed.Under the protection of nitrogen,700°C heat treatment,a core-shell bifunctional catalyst?B,N-TiO₂/B,N-C@B₄C-700?have been prepared,which the nano-B₄C as core,surface formed by the B,N co-doping carbon?B,N-C?and B,N co-doping TiO₂?B,N-TiO₂?.The electrochemical test result showed that,which in 0.1MKOH alkaline solution,the B,N-TiO₂/B,N-C@B₄C-700 is close to the catalytic effect with 20%Pt/C for ORR.The initial potential for ORR is 0.92V?vs.RHE?,the half-wave potential is 0.77 V and the limiting current density value is-5mA/cm².For OER,the 10mA/cm² current density value corresponding to the oxygen evolution over potential value is 1.65 V.