Modulating oxygen coverage of Ti3C2Tx MXenes to boost catalytic activity for HCOOH dehydrogenation

Tingting Hou; Qiquan Luo; Qi Li; Hualu Zu; Peixin Cui; Siwei Chen; Yue Lin; Jiajia Chen; Xusheng Zheng; Wenkun Zhu; Shuquan Liang; Jinlong Yang; Liangbing Wang

doi:10.1038/s41467-020-18091-7

Modulating oxygen coverage of Ti₃C₂T_x MXenes to boost catalytic activity for HCOOH dehydrogenation

Nat Commun. 2020 Aug 25;11(1):4251. doi: 10.1038/s41467-020-18091-7.

Authors

Tingting Hou^#¹, Qiquan Luo^#^{2

3}, Qi Li^#¹, Hualu Zu¹, Peixin Cui⁴, Siwei Chen¹, Yue Lin⁵, Jiajia Chen³, Xusheng Zheng³, Wenkun Zhu⁶, Shuquan Liang¹, Jinlong Yang⁷, Liangbing Wang⁸

Affiliations

¹ State Key Laboratory for Powder Metallurgy, Key Laboratory of Electronic Packing and Advanced Functional Materials of Hunan Province, School of Materials Science and Engineering, Central South University, 410083, Changsha, Hunan, P. R. China.
² Institutes of Physical Science and Information Technology, Anhui University, 230601, Hefei, P.R. China.
³ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, 230026, Hefei, P. R. China.
⁴ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, the Chinese Academy of Sciences, 210008, Nanjing, Jiangsu, P. R. China.
⁵ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, 230026, Hefei, P. R. China. linyue@ustc.edu.cn.
⁶ State Key Laboratory of Environment-friendly Energy Materials, Southwest University of Science and Technology, 621010, Mianyang, Sichuan, P. R. China.
⁷ Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, 230026, Hefei, P. R. China. jlyang@ustc.edu.cn.
⁸ State Key Laboratory for Powder Metallurgy, Key Laboratory of Electronic Packing and Advanced Functional Materials of Hunan Province, School of Materials Science and Engineering, Central South University, 410083, Changsha, Hunan, P. R. China. wanglb@csu.edu.cn.

^# Contributed equally.

Abstract

As a promising hydrogen carrier, formic acid (HCOOH) is renewable, safe and nontoxic. Although noble-metal-based catalysts have exhibited excellent activity in HCOOH dehydrogenation, developing non-noble-metal heterogeneous catalysts with high efficiency remains a great challenge. Here, we modulate oxygen coverage on the surface of Ti₃C₂T_x MXenes to boost the catalytic activity toward HCOOH dehydrogenation. Impressively, Ti₃C₂T_x MXenes after treating with air at 250 °C (Ti₃C₂T_x-250) significantly increase the amount of surface oxygen atoms without the change of crystalline structure, exhibiting a mass activity of 365 mmol·g^-1·h^-1 with 100% of selectivity for H₂ at 80 °C, which is 2.2 and 2.0 times that of commercial Pd/C and Pt/C, respectively. Further mechanistic studies demonstrate that HCOO* is the intermediate in HCOOH dehydrogenation over Ti₃C₂T_x MXenes with different coverages of surface oxygen atoms. Increasing the oxygen coverage on the surface of Ti₃C₂T_x MXenes not only promotes the conversion from HCOO* to CO₂* by lowering the energy barrier, but also weakens the adsorption energy of CO₂ and H₂, thus accelerating the dehydrogenation of HCOOH.