锑烯对O,OH,O2,OOH的吸附特性及氧还原反应的密度泛函理论研究

Study on the Adsorption Characteristics of O,OH,O2,OOH and Oxygen Reduction Reaction on Antimonene Using Density Functional Theory

研究了锑烯对燃料电池阴极氧还原反应中间物O,OH,O2,OOH的吸附特性,通过对吸附能、吸附距离、键长及能带、态密度、电荷转移的分析,比较了锑烯对各中间物的吸附作用,模拟了氧还原反应过程,给出了各步反应自由能变化的趋势图.结果表明:O,OH,O2,OOH在锑烯上最稳定吸附位的吸附能分别为3.81,2.43,1.59,1.04 eV;锑烯上的氧还原反应过程存在四电子途径和二电子途径,且自由能逐渐降低,有自发进行的趋势;锑烯与OOH存在较强的相互作用,这对氧还原反应第一步OOH的吸附及第二步O—O键的断开是有利的,对OH适度的吸附作用也不会限制OH与H结合生成H2O分子进而脱附的过程.以上结果表明,锑烯具有催化燃料电池阴极氧还原反应的潜力,这为实验上进一步探索锑烯作为氧还原反应电催化材料提供了理论参考.

The adsorption characteristics of various oxygen reduction reaction intermediates(O,OH,O2 and OOH)on pristine antimonene have been studied.On analysis of adsorption energy,adsorption distance,bond length,energy band,density of states and charge transfer,the adsorption of various oxygen reduction reaction intermediates on pristine antimonene are compared.The oxygen reduction reaction paths are simulated,and the free energy changes in each step of oxygen reduction reaction are given.The adsorption energies of O,OH,O2 and OOH at the most stable adsorption sites on antimonene are 3.81,2.43,1.59,1.04 eV,respectively.Oxygen reduction reaction has both four-electron and two-electron paths on pristine antimonene.The free energy decreases gradually,which indicates that the reaction can occur spontaneously.There is a strong interaction between pristine antimonene and OOH,which is conducive to the occurrence of the first and second steps of oxygen reduction reaction.In addition,moderate adsorption of OH does not restrict the process of OH binding with H to form H2O.The above results show that antimonene has the ability to catalyze the oxygen reduction reaction of fuel cell cathode,which provides theoretical guides for further experimental exploration of antimonene system as oxygen reduction reaction electrocatalyst materials.