Asymmetric Ru–O–Sn site engineering accelerates proton transfer and inhibits over-oxidation for efficient oxygen evolution reaction
Wangkai Zhou, Jinnan Xu, Zhuangzhi Sun, Chunyong Zhang, Pin Zhou, Hengfei Qin, Yuebin Lian, Yaqiong Su, Jirong Bai
Abstract
RuO<sub>2</sub> is a powerful alternative to IrO<sub>2</sub> catalyst for acidic oxygen evolution reaction (OER), but its widespread application is hampered by its susceptibility to degradation in acidic environments. This instability is primarily due to the detrimental involvement of lattice oxygen, culminating in the formation of the labile RuO<sub>4</sub> species and large amount of unstable oxygen vacancies. In this context, the electronic configuration and the local coordination environment of RuO<sub>2</sub> are precise tailored by Sn doping. The resulting asymmetric Ru–O–Sn structure accelerates proton transfer and facilitates the formation of high oxidation state Ru centers. The resulting Sn-doped RuO<sub>2</sub> electrocatalyst has demonstrated remarkable OER performance in 0.5 M H<sub>2</sub>SO<sub>4</sub>, with a minimum overpotential of 197 mV at a current density of 10 mA cm<sup>–2</sup> and impressive durability. The proposed strategy involves the incorporation of Sn into the RuO<sub>2</sub> lattice, which reduces the Ru–O covalency, inhibits over-oxidation and reduces the adsorption energy of reaction intermediates, resulting in a significant improvement in catalyst activity and stability.