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ISEP - Departamento de Física

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Browsing ISEP - Departamento de Física by Field of Science and Technology (FOS) "Engenharia e Tecnologia"

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  • Gold Single Atom Doped Defective Nanoporous Copper Octahedrons for Electrocatalytic Reduction of Carbon Dioxide to Ethylene
    Publication . Zhao, Yang; Wang, Yanan; Yu, Zhipeng; Song, Chao; Wang, Jingwei; Huang, Haoliang; Meng, Lijian; Liu, Miao; Liu, Lifeng
    Electrocatalytic CO2 reduction into high-value multicarbon products offers a sustainable approach to closing the anthropogenic carbon cycle and contributing to carbon neutrality, particularly when renewable electricity is used to power the reaction. However, the lack of efficient and durable electrocatalysts with high selectivity for multicarbons severely hinders the practical application of this promising technology. Herein, a nanoporous defective Au1Cu single-atom alloy (DeAu1Cu SAA) catalyst is developed through facile low-temperature thermal reduction in hydrogen and a subsequent dealloying process, which shows high selectivity toward ethylene (C2H4), with a Faradaic efficiency of 52% at the current density of 252 mA cm−2 under a potential of −1.1 V versus reversible hydrogen electrode (RHE). In situ spectroscopy measurements and density functional theory (DFT) calculations reveal that the high C2H4 product selectivity results from the synergistic effect between Au single atoms and defective Cu sites on the surface of catalysts, where Au single atoms promote *CO generation and Cu defects stabilize the key intermediate *OCCO, which altogether enhances C−C coupling kinetics. This work provides important insights into the catalyst design for electrochemical CO2 reduction to multicarbon products.
    2025Journal article Open access Show more
  • Ir Nanoparticles Synergistically Regulated by B, N Co-Doping in Carbon for pH-Universal Bifunctional Electrocatalysts towards Energy-Efficient Hydrogen Production
    Publication . Huang, Hongli; Meng, Lijian; li, Haibo; Li, Rui; Zeng, Suyuan; Yao, Qingxia; Chen, Hongyan; Qu, Kong-Gang
    The ultralow-potential hydrazine oxidation reaction (HzOR) can be integrated with hydrogen evolution reaction (HER) to construct the overall hydrazine splitting (OHzS) system, thus realizing energy-saving hydrogen production. Meanwhile, the real electrocatalytic processes normally involve the constantly changed pH and also need to operate under different pH conditions. Therefore, designing advanced pH-universal electrocatalysts with high compatibility for HER and HzOR is of greatly practical significance. Herein, ultrafine Ir nanoparticles embedding in B, N-codoped carbon (Ir/BNC) were facilely synthesized with one Ir-based complex and boric acid by simple mixing and pyrolysis. To reach the current density of 10 mA cm−2, the bifunctional Ir/BNC merely demands the low potentials of −4.8/-6.3/-38.5 mV for HER, 7.5/157.8/330.1 mV for HzOR, and 19/236/358 mV for OHzS in the alkaline, neutral and acidic electrolytes, respectively, all greatly outperforming commercial Pt/C and displaying the huge energy-saving advantage for pH-universal hydrogen generation over the conventional water splitting. Underlyingly, the codoping of abundant B and N heteroatoms with different electronic modulation effects can play synergistical roles to Ir active sites, endowing with the pH-universal multifunctionality as well as the boosted intrinsic unit activity. Additionally, the large surface area, rich pores and highly graphitized carbon also collectively ensure the remarkable apparent performance for bifunctional HER and HzOR. This work supplies a promising strategy for exploiting pH-universal HER and HzOR bifunctional electrocatalysts, greatly potential to the practical energy-efficient hydrogen generation.
    2025Journal article Restricted access Show more