Browsing by Author "Xu, Kaiyang"
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- Atomic Dispersion of Scandium in Electrochemically Reduced Copper Oxide Nanosheets for Efficient Electrocatalytic CO2 Reduction to C2+ ProductsPublication . Zhao, Yang; Zeng, Binwen; Huang, Haoliang; Yang, Huanhuan; Yu, Zhipeng; Song, Chao; Wang, Jingwei; Xu, Kaiyang; Xiang, Xinyi; Wang, Wei; Lin, Fei; Meng, Sheng; Meng, Lijian; Cui, Zhiming; Liu, LifengConverting CO2 into value-added chemicals and fuels through electrochemical CO2 reduction reaction (CO2RR) has been acknowledged as a disruptive technology for chemical industry and an important means to realizing carbon neutrality. However, it remains challenging to achieve high selectivity for C2+ products at a large current density with a low overpotential. Herein, we report a scandium (Sc) single-atom-doped CuO nanosheet (Sc1CuO NS) electrocatalyst for efficient and durable CO2-to-C2+ conversion. The optimal Sc1CuO NS catalyst achieves a maximal C2+ Faradaic efficiency of 73 ± 1.8 % at 475.2 mA cm−2 under an ultralow potential of −0.6 V versus the reversible hydrogen electrode (RHE) and maintains stable CO2-to-C2+ conversion at ∼206 mA cm−2 with a > 60 % Faradaic efficiency for 47 h without degradation. In-situ spectroscopy measurements combined with density functional theory (DFT) calculations reveal that the electron transfer from Sc to Cu enhances the activation of CO2 to *CO. Moreover, the in-situ electrochemical reduction of CuO generates abundant undercoordinated Cu0 sites, featuring tensile-strained Sc-(O)-Cu motifs, which serve as active centers that reduce the reaction barrier for Csingle bondC coupling. This work highlights the importance of rare-earth doping combined with in-situ electrochemical surface reconstruction of CuO as an effective catalyst design strategy to boost CO2-to-C2+ conversion performance.
- Sulfur and phosphorus co-doped FeCoNiCrMn high-entropy alloys as efficient sulfion oxidation reaction catalysts enabling self-powered asymmetric seawater electrolysisPublication . Yu, Zhipeng; Boukhvalov, Danil W.; Tan, Hao; Xiong, Dehua; Feng, Chuangshi; Wang, Jingwei; Wang, Wei; Zhao, Yang; Xu, Kaiyang; Su, Weifeng; Xiang, Xinyi; Lin, Fei; Huang, Haoliang; Zhang, Fuxiang; Zhang, Lei; Meng, Lijian; Liu, LifengSeawater electrolysis (SWE) represents a promising approach to green hydrogen (H2) production but currently faces substantial challenges such as the interference of chlorine chemistry and high energy consumption. In this work, we demonstrate that by replacing the energy-demanding oxygen evolution reaction (OER) with the sulfion oxidation reaction (SOR) and by implementing the concept of bipolar membrane (BPM) electrolysis in an acid-base dual electrolyte system, not only can the notorious chlorine evolution reaction (CER) be completely circumvented, but the energy consumption of SWE be significantly reduced. To do so, we develop a sulfur and phosphorus co-doped FeCoNiCrMn high entropy alloy (HEA-SP) catalyst, which shows good electrocatalytic performance for the SOR in alkaline-saline water. This can be attributed to the abundant lattice defects and strains in HEA-SP, leading to a high density of active sites and an optimized electronic structure favorable for the SOR. Moreover, density functional theory calculations and in situ Raman spectroscopy characterization reveal the crucial role of imperfect sulfur coverage on the HEA in facilitating the formation of Sx clusters during the SOR. Using the HEA-SP as anode catalysts, the SOR-assisted SWE only needs electrical energy of 0.253 kWh to produce one cubic meter of H2 at 100 mA cm−2, in the presence of a BPM. Impressively, chlorine-free H2 production from seawater and upgrading of sulfions to valuable sulfur can occur simultaneously and spontaneously at 10 mA cm−2, highlighting the great potential of the HEA-SP catalysts and the asymmetric cell design to enable energy- and cost-effective seawater electrolysis.