In-situ synthesis of Cr2O3-enhanced bifunctionality in walnut-like Pt/CrN for methanol-assisted high-efficiency hydrogen generation

作者：Zhou, Qiuman; Chen, Peirong; Pan, Junda; Tian, Xinlong; Yan, Yurong^*

来源：International Journal of Hydrogen Energy, 2024, 55: 1495-1504.

DOI：10.1016/j.ijhydene.2023.12.138

• Synergistic effect
• Bifunctionality
• MOR/HER

Methanol-assisted water electrolysis offers a promising alternative for low-voltage green hydrogen generation. Herein, we report the design and in-situ synthesis of Cr2O3, achieved by pyrolyzing a coordination polymer, to serve as cocatalysts. The Cr2O3 cocatalyst enhances the bifunctionality of the walnut-like Pt/CrN catalyst, leading to remarkable electrocatalytic activity in the methanol oxidation reaction (MOR) and hydrogen evolution re -action (HER) compared to Pt/CrN catalyst. Experimental data confirmed that Cr2O3 as a promoter accelerates the water dissociation, resulting in the formation of OHad. Additionally, it reduces the d-band center of Pt, favoring the optimization of the Gibbs free energy of intermediates. Moreover, the walnut-like Cr2O3-CrN facilitates mass diffusion and electron transfer. The synergistic effect between Cr2O3 and CrN, along with the presence of a hetero-interface, contributes to the enhancement of MOR/HER electrocatalytic activity. Thanks to these ad-vantageous characteristics, the as-prepared Pt/Cr2O3-CrN catalysts exhibit superior MOR/HER performance, achieving a mass activity of 1.425 A mgPt- 1 for MOR and an overpotential of 42 mV at a current density of 10 mA cm-2. Furthermore, with the Pt/Cr2O3-CrN as a bifunctional catalyst for both MOR and HER, the methanol-assisted electrolyzer only requires a cell voltage of 0.628 V to deliver a current density of 10 mA cm-2 for 10 h.

• 单位
  海南大学; 广东工业大学