(華僑大學(xué) 材料科學(xué)與工程學(xué)院 應(yīng)用化學(xué)系，廈門 361021)
摘 要: 采用復(fù)合電沉積結(jié)合堿溶制備Ni-S/LaNi5多孔復(fù)合電極，并采用SEM、EDS 和XRD等技術(shù)表征電極的表面形貌、元素組成和鍍層的晶形結(jié)構(gòu)。運用陰極極化曲線研究該電極在20%(質(zhì)量分?jǐn)?shù))NaOH溶液中的析氫電催化性能，通過間斷恒電位電解、長時間恒電位電解研究電極的穩(wěn)定性，用長時間電解后開路電位和陽極極化探討電極穩(wěn)定性的原因。結(jié)果表明：與電沉積Ni-S多孔電極相比，Ni-S/LaNi5多孔復(fù)合電極具有較低的析氫過電位和電化學(xué)反應(yīng)阻抗及較大的交換電流密度和比表面積。在Ni-S多孔及Ni-S/LaNi5多孔復(fù)合電極上，析氫反應(yīng)的表觀活化自由能分別為78.08和49.41 kJ/mol，Ni-S/LaNi5多孔復(fù)合電極表現(xiàn)出較高的析氫電催化活性和穩(wěn)定性。
關(guān)鍵字: LaNi5；多孔復(fù)合電極；復(fù)合電沉積；析氫；電催化
（Department of Applied Chemistry, College of Materials Science and Engineering, Huaqiao University,
Xiamen 361021, China）
Abstract:The Ni-S/LaNi5 porous composite electrodes were prepared by composite electrochemical deposition technique in combination with alkaline dissolving. The corresponding micrographs, element component and structures of the Ni-S/LaNi5 porous composite electrode were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDS) and X-ray diffractometry (XRD). Their electrocatalytic characteristics for hydrogen evolution reaction (HER) in 20% (mass fraction) NaOH solution were investigated by cathodic polarization curves (CPC). Their stabilization was studied by constant potential with discontinuity electrolysis and constant potential electrolysis. The reason of the electrode stabilization was discussed by open-circuit potential (OCP) after constant potential electrolysis and anodic polarization curves. The results show that the Ni-S/LaNi5 porous composite electrode for HER exhibits a lower overpotential and a higher exchange current density than the Ni-S porous electrode. The apparent activation energies of HER on the Ni-S porous and Ni-S/LaNi5 porous composite electrode are 78.08 and 49.41 kJ/mol, respectively. Thus, the Ni-S/LaNi5 porous composite electrode possesses a superior electrocatalytic activity and stability for HER corresponding to the Ni-S porous electrode.
Key words: LaNi5; porous composite electrode; composite electrodeposition; hydrogen evolution; electro-catalysis
