摘要
MXene has attracted great attention due to its high conductivity,large specific surface area and tunable surface functional groups.However,MXene(e.g.,Ti_(3)C_(2))nanosheets tend to stack and mainly offer in-plane sites,showing limited capability in improving the oxygen reduction reaction(ORR)performance of iron phthalocyanine(FePc).In this study,mesoporous Ti_(3)C_(2)(Meso-Ti_(3)C_(2))loaded FePc(FePc/Meso-Ti_(3)C_(2))catalysts were prepared by a simple ultrasonic liquid-phase compounding strategy.Meso-Ti_(3)C_(2)possesses abundant mesopores and edge sites,which optimize the coordination environment and the electronic structure of the FeN4 center in FePc.This optimization improves the mass transfer and the accessibility of the active sites,synergistically enhancing the ORR performance of FePc.As a result,FePc/Meso-Ti_(3)C_(2)shows excellent ORR activity and stability under alkaline conditions with a half-wave potential of 0.914 V against the reversible hydrogen electrode(RHE)and a Tafel slope of 57.2 mV/dec.Furthermore,the zinc-air battery assembled with FePc/Meso-Ti_(3)C_(2)delivers a peak power density of 183.1 mW/cm^(2)and a good long-term discharge stability,exceeding those of FePc/Ti_(3)C_(2)and commercial 20%Pt/C catalysts(20%Pt by mass).
MXene因其高导电性、大比表面积和可调表面官能团而受到广泛关注。然而,MXene(如Ti_(3)C_(2))纳米片极易堆叠,其负载位点主要为面内位点,对酞菁铁(phthalocyanine,FePc)的氧还原性能提升有限。该文采用简单的超声液相复合策略制备了介孔Ti_(3)C_(2)(Meso-Ti_(3)C_(2))负载的FePc催化剂(FePc/Meso-Ti_(3)C_(2))。Meso-Ti_(3)C_(2)具有大量介孔和丰富的边缘位点,可优化FePc分子的四配位FeN4中心的配位环境和电子结构,改善传质并提高活性位点的可及性,从而提升氧还原性能。FePc/Meso-Ti_(3)C_(2)在碱性条件下展现出优异的氧还原反应活性和稳定性,半波电位为0.914 V vs.RHE,Tafel斜率为57.2 mV/dec。以FePc/Meso-Ti_(3)C_(2)为催化剂的锌空气电池峰值功率密度为183.1 mW/cm^(2),且具有高循环稳定性,性能超过FePc/Ti_(3)C_(2)和商用20%Pt/C催化剂(Pt质量占20%)。
基金
National Outstanding Youth Science Foundation,China(No.52225204)。
