中药渣生物炭活化制备碳基电催化剂及其氧还原反应催化性能研究

Study on the Preparation and Performance of Metal-free Electrocatalyst from Biochar of Chinese Medicine Slag Toward Oxygen Reduction Reaction

以废弃物生物质中药渣为原料,以ZnCl_(2)为活化剂,通过热解活化两步法制备了生物质碳基氧还原电催化剂。采用SEM、氮气等温吸脱附测试、XRD、XPS、元素分析和电化学工作站等材料测试方法,分析了所制备碳基电催化剂的结构特征以及氧还原反应性能。结果表明,当活化剂与生物炭质量比为4∶1,活化温度为800℃时,所制备的ZC-4∶1-800阴极氧还原电催化剂性能最佳。ZC-4∶1-800具有介孔和微孔结构,比表面积可达970.4 m^(2)/g,其起始电位为0.9 V(vs.RHE),半波电位为0.8 V,极限电流密度为4.9 mA/cm^(2),与商业20%Pt/C性能相近。此外,ZC-4∶1-800具有比商业20%Pt/C更好的稳定性和甲醇耐受性,在实际应用中有望作为商业贵金属电催化剂的替代品,同时也为废弃生物质的资源化利用提供了新路径。

Using ZnCl_(2)as an activator,Chinese medicine slag was converted into metal-free carbon electrocatalyst for oxygen reduction reaction through coupled pyrolysis and activation.The structural features of the carbon-based electrocatalysts and the oxygen reduction reaction performance were analyzed with SEM,nitrogen isotherm adsorption-desorption test,XRD,XPS,elemental analysis and electrochemical workstations.Especially,the product obtained with activation agent/biochar mass ratio of 4∶1 under 800℃thermal activation,namely ZC-4∶1-800,which has a mesoporous and microporous structure with a specific surface area of up to 970.4 m^(2)/g,delivered the optimal oxygen reduction electrocatalyst performance,with a starting potential of 0.9 V,a half-wave potential of 0.8 V,and a limit current density of 4.9 mA/cm^(2),which close to that of the commercial 20wt%Pt/C.Besides,it also revealed obviously superior stability and methanol tolerance over 20%Pt/C counterpart,and thus promise great potential as sustainable alternative candidate for practical use.Meanwhile,this work also provides a new path for the resource utilization of waste biomass.