Synthesis And Electrocatalytic Performance Of Nitrogen-doped Carbon Supported Nickel-based Catalysts

With the rapid consumption of non-renewable energy sources such as fossil fuels,exploring new energy sources have attracted widespread attention worldwide.Environmental problems caused by fossil fuel consumption have become one of the most significant challenges in the 21st century,which has been urging scientists to find an alternative clean and sustainable energy production or conversion technology.Fuel cell is one of the promising clean energy devices.In a fuel cell,the reaction rate of oxygen reduction reaction on cathode determines the overall efficiency of fuel cell.So far,the main catalyst used for fuel cells is the platinum-based catalysts.However,platinum catalysts can not be used in large-scale commercial application of fuel cells due to its resource shortage,high cost,easy poisoning and poor stability.Therefore,there is an urgent demand to develop a high effective catalyst with low cost,good stability as a substitute for platinum catalyst.This thesis focuses on the research of non-precious metal catalysts.The main results are as follows:1.A low-cost,high-activity nanotube-like MnO-Ni/N-C electrocatalyst was successfully synthesized through a two-step calcination method.The results of electrochemical experiments show that the MnO-Ni/N-C catalyst has superior catalytic activity for ORR far exceeding that of pure Ni and pure MnO as electrocatalysts.The synergy between Ni and MnO greatly improves the electrocatalysis of MnO-Ni/N-C composites.The ORR process was proceeded by an efficient four-electron pathway and was given a very low H₂O₂yield.It also has better electrocatalytic stability and methanol tolerance than Pt/C.2.The Cu Ni/N-C bimetallic alloy supported on nitrogen-doped carbon was prepared by hydrothermal and calcination method.The influence of different supports on catalytic performance was discussed.The results of electrochemical experiments show that Cu Ni/N-C with g-C₃N₄as a precursor for ORR has the electrocatalytic activity close to commercial Pt/C and better stability and current density than commercial Pt/C.The ORR process is catalyzed by"quasi-four-electron"process,which greatly reduces the excessively high overpotential in the ORR process.3.The CoNi alloy nanoparticles supported on nitrogen-doped carbon was synthesized by hydrothermal and calcination method.Characterization by SEM and TEM showed that the morphological characteristics of the catalyst are tubular N-C nanotubes.The successfully prepared CoNi/N-C catalyst has higher current density and more stable ORR electrocatalytic activity and methanol resistance than the commercially available Pt/C catalyst in alkaline solution.