Highly Efficient Oxygen Evolution by a Thermocatalytic Process Cascaded Electrocatalysis Over Sulfur-Treated Fe-Based Metal–Organic-Frameworks
Kun Feng,1 Duo Zhang,2 Fangfang Liu,1 Hui Li,2 Jiabin Xu,1 Yujian Xia,1 Youyong Li,1 Haiping Lin,*,1 Shuao Wang,2 Mingwang Shao,1 Zhenhui Kang,*,1 and Jun Zhong*,1
1Institute of Functional Nano and Soft Materials Laboratory (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University Suzhou 215123, China
The oxygen evolution reaction (OER) is a bottleneck process for water splitting and finding highly efficient, durable, low-cost, and earth-abundant electrocatalysts is still a major challenge. Here a sulfur-treated Fe-based metal–organic-framework is reported as a promising electrocatalyst for the OER, which shows a low overpotential of 218 mV at the current density of 10 mA cm-2 and exhibits a very low Tafel slope of 36.2 mV dec-1 at room temperature. It can work on high current densities of 500 and 1000 mA cm-2 at low overpotentials of 298 and 330 mV, respectively, by keeping 97% of its initial activity after 100 h. Notably, it can achieve 1000 mA cm-2 at 296 mV with a good stability at 50°C, fully fitting the requirements for large-scale industrial water electrolysis. The high catalytic performance can be attributed to the thermocatalytic processes of H+ capture by –SO3 groups from *OH or *OOH species, which cascades to the electrocatalytic pathway and then significantly reduces the OER overpotentials.