產氫反應在鎳與鈷磷化物上的反應機理

Abstract

氫氣是一種未來有望取代化石燃料的能源，並且使用電解水來產生氫氣的方式，方向上非常符合現在要朝著永續發展的綠色能源，本篇研究非貴金屬材料Fex-Ni1Co1-xP，先從多種鎳鈷比例中挑選最佳的比例，再摻入微量鐵形成的三元金屬催化劑在產氫反應上的效果。實驗上使用共沉澱法進行鍛燒生成金屬氧化物，再使用化學氣相沉積法製備金屬磷化物。本研究鑑定利用量散射光譜儀(EDX)、X光光電子光譜(XPS)分析催化劑之表面金屬含量及整體組成，利用X光粉末繞射儀(X-Ray Powder Diffraction analysis, XRD) 、掃描式電子顯微鏡(Scanning Electron Microscope, SEM) 進行晶體結構和表面結構分析。在測定產氫反應活性方面，則由電化學測量儀測量過電位和塔菲爾斜率，以及電化學活性表面積，在研究結果中發現酸性環境下Fe0.1-Ni1Co0.9P在 10 mA/cm2時過電位為108 mV，Tafel 斜率為 75.9 mV/dec，有最好的HER活性。根據鑑定結果，最好的催化劑Fe0.1-Ni1Co0.9P有最大的ECSA為14.21 mF/cm2，主要在樣品保持Ni大於50%時的Ni2P的晶型下摻入CoP形成的Ni2P/CoP 雙質結構可以更加有效的提升過電位，傾向於 Volmer-Heyrovsky 反應機構並有良好的 Tafel 斜率。Hydrogen gas is a promising future alternative to fossil fuels as an energy source, and the use of electrolysis to generate hydrogen from water aligns well with the current direction towards sustainable green energy. In this study, we focused on a non-noble metal material, Fex-Ni1Co1-xP, and aimed to determine their optimal compositions for the best hydrogen evolution reaction (HER) activity under acidic conditions.The materials were prepared using a co-precipitation method to generate metal oxides, followed by chemical vapor deposition to synthesize metal phosphides.The characterization of the catalysts involved analysis of surface and chemical compositions using techniques of Energy Dispersive X-ray Spectroscopy (EDX) and X-ray Photoelectron Spectroscopy (XPS). Crystal and surface structure analyses were conducted using X-Ray Powder Diffraction analysis (XRD) and Scanning Electron Microscopy (SEM). In terms of evaluating the hydrogen production activity, overpotential and Tafel slope were measured using an electrochemical measurement device, along with the determination of electrochemically active surface area (ECSA).Our research findings indicate that Ni1Co1P in the presence of a dual-phase Ni2P/CoP phases can effectively enhance the overpotential and favor the Volmer-Heyrovsky reaction mechanism with a good Tafel slope. Further, Fe0.1-Ni1Co0.9P exhibited the best performance with an overpotential of 108 mV at 10 mA/cm2 and a Tafel slope of 75.9 mV/dec, along with the largest ECSA of 14.21 mF/cm2.