不同晶型MnO_(2)纳米阵列的可控合成及其电催化析氧性能

Crystalline Form Controlled Synthesis of MnO_(2) Nanoarrays for Electrocatalytic Oxygen Evolution Performance

采用一步水热法,通过改变反应温度和硫酸的用量,在碳纸(CFP)表面可控合成了α‑MnO_(2)纳米线和δ‑MnO_(2)纳米片阵列,研究了MnO_(2)纳米阵列的电催化析氧反应(OER)性能。结果表明,在碱性介质中,α‑MnO_(2)纳米线阵列的OER活性优于δ‑MnO_(2)纳米片阵列,在电流密度为10 mA·cm^(-2)时,α‑MnO_(2)纳米线阵列的析氧过电位为444 mV(δ‑MnO_(2)纳米片的过电位为522 mV)。通过X射线光电子能谱的表征分析可知,更高含量的Mn^(3+)和表面更丰富的氧空位浓度是α‑MnO_(2)纳米线阵列催化活性更高的原因。

Two kinds of MnO_(2) nanoarrays,includingα‑MnO_(2) nanowires andδ‑MnO_(2) nanosheets,were synthesized on carbon fiber paper(CFP)via the one‑step hydrothermal method by changing the temperature and the addition of sulfuric acid,respectively.Moreover,the oxygen evolution reaction(OER)properties for the MnO_(2) nanoarrays were studied.The results showed that the performance ofα‑MnO_(2) nanowires outperformedδ‑MnO_(2) nanosheets in alkaline medium and the overpotential ofα‑MnO_(2) was 444 mV under 10 mA·cm^(-2) current density(the overpotential ofδ‑MnO_(2) was 522 mV).According to the analysis of X‑ray photoelectron spectroscopy,the higher content of Mn^(3+)and more abundant oxygen vacancies on the surface are the reasons for the higher catalytic activity ofα‑MnO_(2) nanowires.