本研究采用简单的路易斯酸水热预处理和高温热解制备了具有Co-N活性中心的钴氮掺杂木质衍生碳基双功能催化剂(CoHNC),并对其结构与性能进行研究.结果表明,路易斯酸(CoCl2)可以部分水解木材中的纤维素和半纤维素,在细胞壁上形成丰富的微介孔,所得碳材料比表面积高达1 008.02m2/g;预处理过程同步引入金属原子,在热解过程中形成Co-N活性位点.CoHNC独特的分级孔结构有利于电解质/氧气等物质的高效扩散及高密度活性位点的暴露,而Co—N结构可以有效调节催化局部微环境,进而提高多相催化性能.CoHNC表现出优异的电催化性能,在0.1mol/LKOH溶液中,其氧还原半波电位达0.869 V vs.RHE,在电流密度为10 mA/cm2时,氧析出过电位为274 mV,电位差ΔE仅为0.635 V,优于商用Pt/C和RuO2.
Preparation and Electrocatalytic Performances of Cobalt-nitrogen Doped Wood-derived Carbon
In this study,a cobalt-nitrogen doped wood-derived bifunctional catalyst(CoHNC)with Co-N active sites was prepared via a sim-ple Lewis acid hydrothermal pretreatment and followed by a high-temperature pyrolysis.The physicochemical structures and electrochemical properties of CoHNC were investigated.The results showed that Lewis acids could partly hydrolyze the cellulose and hemicellulose in the wood,re-sulting in abundant nanopores,and a high specific surface area of 1 008.02 m2/g.Metal atoms coordinate with the oxygen-containing functional groups during hydrothermal pretreatment,which was then converted into Co-N active sites after pyrolysis.The hierarchical pore structure of CoHNC facilitated the efficient diffusion of electrolyte/oxygen and the exposure of high-density active sites.The Co—N structure could effectively regulate the microenvironment of the catalyst,and thus improve the catalytic performance.CoHNC presented excellent oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)activities with a positive half-wave potential of 0.869 V vs.RHE in 0.1 mol/L KOH solution,a OER overpotential of 274 mV at a current density of 10 mA/cm2 and a ΔE of only 0.635 V,which outperform those of commercial Pt/C and RuO2.
万方数据
维普
