Electrocatalytic properties of transition metal oxides for oxygen evolution reaction

Electrocatalysis of the transition metal oxides for the oxygen evolution reaction has been reviewed. The mechanisms of the oxygen evolution reaction and the electrical properties of the oxides are simultaneously discussed. It is suggested that some assumptions used in the deduction of the mechanism from the reaction parameters may not be always correct, especially in the potential distribution in the interface between the electrode and the electrolyte. Many transition metal oxides tested as the anode material for the oxygen evolution reaction are summarized. From the comparison in the overvoltages in the oxygen evolution reaction, the sequence of the electrocatalytic activity is concluded to be RuO₂ > IrO₂ > Co and Ni containing oxides > Fe, Mn and Pb containing oxides. The proposed factors contributing to the electrocatalysis are mainly divided into two divisions: one is the electron transfer and the other is the strength of M-O. The work function is proposed to be another important factor for the electrocatalysis, and its influence on the electrocatalysis is also discussed.     

不同种植方式西瓜果实农药残留的比较

为明确不同栽培种植方式产出西瓜果实的农药残留状况及其差异性，本文以大棚、小拱棚、露地3种种植方式产出的65份西瓜样品为研究对象，在完成样品中60种农药残留定量分析的基础上，通过慢性、急性膳食风险分析、风险排序等技术方法，探讨了3种种植方式产出西瓜果实残留农药的差异性。结果表明:部分样品存在残留农药的现象，但其慢性和急性膳食风险均不高；3种种植方式中，露地种植方式样品残留农药种类最多，为9种，且极低风险样品占比也低于其余2种方式，为76%；此外，3种种植方式需重点关注的风险相对较高残留农药种类不同，大棚为三唑磷，小拱棚为苯醚甲环唑、丙溴磷、氯氟氰菊酯，露地种植为三唑磷、丙溴磷、咪鲜胺。综合以上分析可以得出:3种种植方式中，露地种植产出西瓜残留农药风险相对较高，宜根据风险相对较高残留农药种类的差异，分别加强监管。