Mn <sup>2+</sup> ‐doped Co <sub>3</sub> Si <sub>2</sub> O <sub>5</sub> (OH) <sub>4</sub> serpentine nanosheets with tuned d‐band centers for efficient oxygen evolution in alkaline and neutral electrolytes
Shicheng Huang, Yulong Zhou, Lian Duan, Dingzhong Luo, Baopeng Yang, Gen Chen, Xiaohe Liu, Jianguo Tang, Ning Zhang
Abstract
Abstract Serpentine structured Co 3 Si 2 O 5 (OH) 4 is inexpensive, chemically stable, and electrochemically active in oxygen evolution reactions (OER). However, the OER activity of Co 3 Si 2 O 5 (OH) 4 materials is still unfavorable due to the low active sites. Here, Mn 2+ ‐doped Co 3 Si 2 O 5 (OH) 4 serpentine nanosheets with tuned d‐band centers are achieved for efficient oxygen evolution in alkaline and neutral electrolytes. The Co x Mn 3− x Si 2 O 5 (OH) 4 serpentine nanosheets are synthesized by a simple hydrothermal method. The optimized Co 2.4 Mn 0.6 Si 2 O 5 (OH) 4 serpentine nanosheets showed favorable OER overpotentials as well as stable durability in KOH solution and phosphate buffer solution, which were superior to most of the Co‐based and Mn‐based OER electrocatalysts. The in situ Raman spectroscopy shows that the materials are kept well in the electrochemical OER environments. Further density functional theory shows that the d‐band center of Co x Mn 3− x Si 2 O 5 (OH) 4 serpentine nanosheets is shifted more upward in comparison with pristine Co 3 Si 2 O 5 (OH) 4 . The changes in the d‐band center increase the adsorption of intermediates, optimize the reaction steps, and lower the energy barriers of the OER. That is the main reason for the OER enhancement Mn 2+ ‐doped Co 3 Si 2 O 5 (OH) 4 . This work gives an efficient strategy to design cheap and stable electrocatalytic materials for OER in a broad pH environment.