多晶型MnO_(2)-Ru复合催化剂的制备及其电催化水解析氧性能的研究

Preparation of Polymorph MnO_(2)-Ru Composite Catalyst and Its Electrocatalytic Performance for Oxygen Evolution in Water

在二氧化锰(MnO_(2))中引入杂原子是调整电化学水氧化催化活性位点的有效方法。在电催化析氧反应(OER)中,虽然已经研究出了许多MnO_(2)的改性方法,但很少有研究以MnO_(2)为主体,讨论MnO_(2)晶型对催化活性的影响。基于此,本文制备了4种晶型的MnO_(2)(α-MnO_(2)、β-MnO_(2)、γ-MnO_(2)和δ-MnO_(2)),并系统地研究了Ru加入MnO_(2)制备得到的催化剂(x-MnO_(2)-Ru)的OER性能。线性扫描伏安法和计时电位法测试结果表明,β-MnO_(2)在Ru加入后得到的催化剂(β-MnO_(2)-Ru)电化学性能最佳,在电流密度为10 mA·cm^(-2)时拥有300 mV的较低过电位,而且运行24 h后仍保持较好的催化活性。结合表征发现,β-MnO_(2)-Ru具有较多的Mn^(3+)和缺陷氧空位,从而具有优异的电催化性能。

The introduction of heteroatoms into manganese dioxide(MnO_(2))is an effective method to adjust the active site of electrochemical water oxidation catalysis.Although many modification methods for MnO_(2)have been studied in electrocatalytic oxygen evolution reaction(OER),few studies have focused on the influence of regulating different crystal forms of MnO_(2)on catalytic activity.This article prepared four different crystal forms of MnO_(2)(α-MnO_(2),β-MnO_(2),γ-MnO_(2)andδ-MnO_(2)),and systematically studied the catalytic performance of the catalyst(x-MnO_(2)-Ru)prepared by adding Ru toα-MnO_(2),β-MnO_(2),γ-MnO_(2)andδ-MnO_(2)for OER.The results of linear sweep voltammetry and chronopotentiometry measurements show that the catalyst prepared by adding Ru toβ-MnO_(2)(β-MnO_(2)-Ru)has the best electrochemical performance.β-MnO_(2)-Ru shows a low overpotential(300 mV at 10 mA·cm-2)and outstanding catalytic activity with small degradation after 24 h operation.It is found thatβ-MnO_(2)-Ru exhibits excellent electrocatalytic performance due to its abundance of Mn^(3+)and defect oxygen vacancies.