The Preparation And Catalytic Performance Of Laser Modified BN Supported Electrochemical Catalyst Composites

Oxygen evolution reaction(OER)is the key material for fuel cells,metal-air batteries and water splitting.Among them the support effect plays a vital role in the catalytic activity of the catalysts.Carbon-based materials are the most common support materials,but the carbon-based materials have weak resistance to electrochemical corrosion.Therefore,developing a new type of support material has important significance.In this thesis,firstly,C,O co-doped insulatedBN nanospheres(BNc,o),which are adopted as precursor for the purposes of pulsed-laser absorption liquid target(PLAL)and photochemical reaction,are modified by PLAL.The structure,morphology and electrical conductivity of BNc,o are investigatedbefore and after PLAL modification,the results show that the laser ablation did not change the morphology and phase of BNc,o nanospheres.Through electrochemical OER performance tests,it was found that pulsed laser-modified BNc,o nanospheres(L-BN)have higher current densities and carrier concentrations,and the theoretical calculations further prove that L-BN nanospheres have metal conductivity.L-BN can be used as electrochemical catalyst support and its conductivity can be comparable to carbon-based materials.Secondly,the IrOx/L-BN composite catalyst was prepared by loading the IrOx on L-BN nanospheres,which showed excellent electrochemical performance,and the overpotential reached 259 mV at 10 mA/cm2 with low Tafel slope of 36.68 mV/dec.After the electrochemical stability test,it was found that the IrOx/L-BN composite catalyst displayed better stability than the carbon-based composite catalyst both at high potential and low potential.According to quantify by chemical analysis of the samples after laser ablation,it was found that the presence of N-C=N bonds can increase the valence of Ir,so as to greatly enhance the catalytic performance.Finally,L-BN supported cobalt oxide(CoOx/L-BN)composite catalyst was in-situsynthesized with the pulsed laser-induced photochemical method.The large surface area of L-BN nanospheres helps to increase the electrochemical specific surface area of the composite catalyst,which can reach 4 times than that of commercially RuO2 catalysts,and the overpotential reaches 310 mV at 10 mA/cm2.The L-BN nanosphere prepared by PLA technology can be used as an excellent support which has broad applications in the field of electrochemistry.