Revealing New Mechanism of Water Electrolysis on CoMo2S4

2022-04-14 L  M  S 】

  A low-cost catalytic material CoMo2S4 has been designed and synthesized by the Photoelectronic Functional Materials and Devices Research Team (hereinafter referred to as "Photoelectronic Team") of Institute of Analysis of Guangdong Academy of Sciences (China National Analytical Center, Guangzhou). The catalyst shows potential to achieve low-cost and efficient hydrogen production.

  The rapid development of industry is accompanied by the exhaustion of fossil energy and increasing carbon dioxide emissions, human society is confronting energy crisis and global climate change. Accelerating the development of clean energy is imminent. Hydrogen (H2) is a pollution-free clean energy with high mass energy density. Hydrogen production by water decomposition using renewable energy has become a global research hotspot. One of the most effective ways to achieve this goal is to convert existing renewable energy sources (such as wind and solar) into electricity and use it directly in conjunction with traditional water electrolysis processes. In China's 14th five-year plan, electrolytic water technology is included as a key research and development project. However, conventional water electrolysis generally requires the use of platinum (Pt) and palladium (Pd) as catalysts, which are expensive and scarce, resulting in high cost of water electrolysis.

  Figure. Hydrogen evolution reaction performance of CoMo2S4 and Pt/C (20%) (left) and crystal structure of CoMo2S4 catalyst adsorbing H2O (right).

  To address this, CoMo2S4 two-dimensional nanosheet was designed and synthesized as the catalytic material by the Photoelectronic Team, and its performance and mechanism were analyzed by electrochemical test, in-situ shielding test, four-probe resistance test and X-ray spectroscopy. Electrochemical tests show that CoMo2S4 possesses high hydrogen evolution reaction (HER) performance with an overpotential of 55 and 150 mV at 10 and 100 mA cm-2, respectively, outperforming Pt/C (20%) . An in-depth mechanism study reveals that the main active site of CoMo2S4 is Mo rather than Co, whereas Co plays a key role in improving the electrical conductivity of the catalyst and thus improving the HER performance. X-ray photoelectron spectroscopy and density of state tests demonstrate that the introduction of Co leads to electron delocalization in the catalyst, making the electrons transport easier and finally endowing the catalyst with better conductive performance. This is the first time that the effect of Co on improving the bulk conductivity of Co-Mo-S catalyst is proposed, which highlights the potency of Co in improving the electrocatalytic HER activity of Mo-S-based materials. Moreover, this work also provides theoretical guidance and data support for rational design of HER catalyst.

  Related work was published in Advanced Functional Materials, a nature index journal, and selected by Chemistry Europe as a Hot Topic (Water Splitting) special paper. The Institute of Analysis of Guangdong Academy of Sciences (China National Analytical Center, Guangzhou) is the signature unit of the first author and corresponding author. The above work was supported by the National Natural Science Foundation of China, the Postdoctoral Program for Innovative Talents and the Special fund project of Guangdong Academy of Sciences to build a first-class research institution in China.

  The Information of Article:

  Cheng, H., Liu, Q., Diao, Y., Wei, L., Chen, J., Wang, F., CoMo2S4 with Superior Conductivity for Electrocatalytic Hydrogen Evolution: Elucidating the Key Role of Co. Adv. Funct. Mater. 2021, 31, 2103732.

  Article Link:

  Hot Topic Special Paper Link: