Browsing by Author "Bai, Xiaowan"

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    CO2/carbonate-mediated electrochemical water oxidation to hydrogen peroxide
    (Springer Nature, 2022) Fan, Lei; Bai, Xiaowan; Xia, Chuan; Zhang, Xiao; Zhao, Xunhua; Xia, Yang; Wu, Zhen-Yu; Lu, Yingying; Liu, Yuanyue; Wang, Haotian
    Electrochemical water oxidation reaction (WOR) to hydrogen peroxide (H2O2) via a 2e− pathway provides a sustainable H2O2 synthetic route, but is challenged by the traditional 4e− counterpart of oxygen evolution. Here we report a CO2/carbonate mediation approach to steering the WOR pathway from 4e− to 2e−. Using fluorine-doped tin oxide electrode in carbonate solutions, we achieved high H2O2 selectivity of up to 87%, and delivered unprecedented H2O2 partial currents of up to 1.3 A cm−2, which represents orders of magnitude improvement compared to literature. Molecular dynamics simulations, coupled with electron paramagnetic resonance and isotope labeling experiments, suggested that carbonate mediates the WOR pathway to H2O2 through the formation of carbonate radical and percarbonate intermediates. The high selectivity, industrial-relevant activity, and good durability open up practical opportunities for delocalized H2O2 production.
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    Highly active and selective oxygen reduction to H2O2 on boron-doped carbon for high production rates
    (Springer Nature, 2021) Xia, Yang; Zhao, Xunhua; Xia, Chuan; Wu, Zhen-Yu; Zhu, Peng; Kim, Jung Yoon (Timothy); Bai, Xiaowan; Gao, Guanhui; Hu, Yongfeng; Zhong, Jun; Liu, Yuanyue; Wang, Haotian
    Oxygen reduction reaction towards hydrogen peroxide (H2O2) provides a green alternative route for H2O2 production, but it lacks efficient catalysts to achieve high selectivity and activity simultaneously under industrial-relevant production rates. Here we report a boron-doped carbon (B-C) catalyst which can overcome this activity-selectivity dilemma. Compared to the state-of-the-art oxidized carbon catalyst, B-C catalyst presents enhanced activity (saving more than 210 mV overpotential) under industrial-relevant currents (up to 300 mA cm−2) while maintaining high H2O2 selectivity (85–90%). Density-functional theory calculations reveal that the boron dopant site is responsible for high H2O2 activity and selectivity due to low thermodynamic and kinetic barriers. Employed in our porous solid electrolyte reactor, the B-C catalyst demonstrates a direct and continuous generation of pure H2O2 solutions with high selectivity (up to 95%) and high H2O2 partial currents (up to ~400 mA cm−2), illustrating the catalyst’s great potential for practical applications in the future.