沉積具催化活性的釕與銥薄膜於鎳反蛋白石結構上並應用於電解水陰極電極

Abstract

本研究使用無電鍍法沿著半徑為660 nm的碗狀鎳反蛋白石結構的表面沉積較具催化活性的釕與銥氧化物，使此電極同時結合高表面積與觸媒的優點。針對釕元素的部分就不同沉積時間、不同熱處理溫度與不同氣體的環境下熱處理分為三部分討論。發現膜厚與觸媒量皆會隨著沉積時間而上升，但膜厚上升意味著表面積下降使得具有最佳催化活性的沉積時間為兩小時。接著由於層狀結構電極中的鎳分別與鈦、釕與銥金屬或其氧化物的熱膨脹係數差異太大，使得在以熱處理方式提升結晶性希望提升電解水在陰極造氫的效能的同時，過高的溫度會使得層與層之間的附著力下降，因此得到最佳的熱處理溫度為200˚C。最後使用不同氣體進行熱處理，搭配XRD與XPS的結果可以發現在相同的結晶性與環境之下，通以氫氣將氧化物薄膜還原成金屬薄膜後，在電解水陰極的性能上較佳。

The catalysts for hydrogen evolution reaction（HER）using Ru or Ir coated half-layer Ni inverse opal in 1 M KOH aqueous solution was investigated. RuO2 and IrO2 thin films were deposited by electroless plating and reduced subsequently to Ru and Ir at 200˚C under hydrogen treatment. The resulting electrode combined the advantage of large surface area and reasonable electro-catalytic activity. Variables such as deposition time, annealing temperature, and various annealing environments played critical roles. From SEM images, ICP-MASS and i-V polarization measurements, we determined the optimized processing condition. The reason is the surface area was decreased by the increased deposition time. According to the result of XRD and the thermal expansion coefficient of different materials on the substrate, the electro-catalytic activity was increased with the crystallinity but suffered from poor adhesion. Comparing both oxidative and metallic states of Ru and Ir films, we concluded that the metallic state revealed better catalytic ability.