摘要
阳极的析氧反应(OER)是限制电解水制氢的主要因素,传统的OER电催化剂由于活性低、稳定性差等缺点无法实现大规模使用。过渡金属氧化物Co_(3)O_(4)是一种很有前景的OER催化剂,但较弱的导电性仍然制约着其电催化性能。通过对Co_(3)O_(4)进行改性以增强电催化活性及稳定性,分别在NaBH4和VCl_(3)水溶液中两步浸泡法合成了富氧空位、V掺杂的Co_(3)O_(4)催化剂。利用XRD、SEM、EDS、TEM、HRTEM、SAED、拉曼光谱、XPS等手段对催化剂的相纯度、晶体结构、微观形貌、含有的官能团及化学键等性质进行测试和分析,并对催化剂进行电化学性能测试。结果表明:氧空位的引入使晶格间距有所增大,V成功掺杂到了Vo-Co_(3)O_(4)/NF(Vo指氧空位)结构中;氧空位和V掺杂协同提高了Co_(3)O_(4)/NF的OER性能。在1 mol/L KOH中,V-Vo-Co_(3)O_(4)/NF仅需253 mV/270 mV的过电位就能驱动50(mA·cm^(-2))/100(mA·cm^(-2))的电流密度,Tafel斜率为71.5 mV/dec,并具有100 h的稳定性。其性能的提升主要归因于V掺杂及氧空位的引入对Co_(3)O_(4)电子构型的调控,低结晶度的表面暴露了更多活性位点,以及亲水性的增强有利于OER过程中反应中间体的吸附和解吸。
Oxygen evolution reaction(OER)at the anode is the main limiting factor for hydrogen production from electrolytic water,and conventional OER electrocatalysts cannot be realized for large-scale utilization due to the drawbacks of low activity and poor stability.The transition metal oxide Co_(3)O_(4) is a promising OER catalyst,but the weaker electrical conductivity restricts its electrocatalytic performance.In this study,the oxygen vacancy-rich,V-doped Co_(3)O_(4) catalysts were synthesized by a two-step immersion method in NaBH 4 and VCl_(3) aqueous solutions respectively,modifying Co_(3)O_(4) to enhance the electrocatalytic activity and stability.The catalyst phrase purity,crystal structure,microstructure,frunctional group and chemical bond et al were detected and analyzed by XRD,SEM,EDS,TEM,HRTEM,SAED,Roman spectra,XPS and so on.The results show that the introduction of oxygen vacancies enlarges the lattice spacing and V is adulterated to Vo-CO_(3)O_(4);oxygen vacancies and V doping synergistically improve the OER performance of Co_(3)O_(4)/NF.V-Vo-Co_(3)O_(4)/NF requires only 253 mV/270 mV overpotentials to drive a current density of 50(mA·cm^(-2))/100(mA·cm^(-2))in 1 mol/L KOH,with a Tafel slope of 71.5 mV/dec and 100 h stability.The enhanced performance is mainly attributed to the modulation of the electronic configuration of Co_(3)O_(4) by V doping and the introduction of oxygen vacancies,the exposure of more active sites on the low crystallinity surface,and the enhancement of hydrophilicity that facilitates the adsorption and desorption of the reaction intermediates during the OER process.
作者
郝根彦
田露
郎学磊
钟达忠
赵强
HAO Genyan;TIAN Lu;LANG Xuelei;ZHONG Dazhong;ZHAO Qiang(Shanxi College of Technology,036000 Shuozhou,China;College of Chemistry and Chemical Engineering,Taiyuan University of Technology,030024 Taiyuan,China;Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization,030024 Taiyuan,China)
出处
《煤炭转化》
CAS
CSCD
北大核心
2024年第2期98-108,共11页
Coal Conversion
基金
国家自然科学基金项目(21975175)
中央引导地方科技发展资金项目(YDZJSX20231A015)。
