| 摘要: | 白金基的奈米顆粒(nanoparticles, NPs)由於優異的效能而被應用於析氫反應(hydrogen evolution reaction, HER)，但是由於白金的高成本以及白金奈米顆粒的利用率較低，而在析氫應用上受到限制。因此降低白金奈米顆粒的尺寸以及提高其利用率為析氫應用的關鍵。為了解決上述問題，本研究以沉澱沉積法(deposition-precipitationmethod) 製備碳支撐的 Pt-奈米團簇(nanocluster, NCs)、Pt-單原(single atoms, SAs)，Pd-NCs、Pd-SAs，PtxPdy-NCs(x/y= 1/2, 1/1,及2/1)，以及PtPdM-NCs(M= Sn 或 Ni)。所製備觸媒之電化學性質、形貌、結構、表面組成、化學組成以及觸媒微結構分別使用旋轉盤電極 (rotating disk electrode, RDE)、高角度環形暗場相掃描電子顯微鏡(high angle annular dark-Field scanning transmission electron microscopy, HAADF STEM)/高 解 析穿透式電子顯微鏡(high resolution transmission electron microscopy, HR-TEM)、X光繞射儀(X-ray diffraction, XRD)、光電子能譜儀(X-ray photoelectron spectroscopy, XPS)、感應耦合電漿原子發射光譜分析儀(inductively coupled plasma-optical emission spectrometer, ICP-OES)以及X光吸收光譜(X-ray absorption spectroscopy, XAS)等儀器鑑定。本研究為三個部分，在第一部份製備 Pt-NCs、Pt-NCs、Pd-NCs、以及Pd-SAs 並與Pt-NPs及Pd-NPs 比較其HER效能，其中又以Pt-NCs以及Pt-SAs展示了最佳的HER效能，其質量活性在-0.05 V的電位下分別為1.3及10.6 A/mgPt，優於Pt-NPs (在-0.05 V的質量活性為0.3 A/mgPt )，此乃因奈米團簇及單原子具有較高白金利用率。但是Pt-NCs以及Pt-SAs在經過12小時計時電流試驗後，其質量活性的衰退分別為39以及65%。為了提升觸媒之HER穩定性，在第二部分的研究製備了雙金屬PtxPdy-NCs。其中又以PtPd-NCs展示了最佳的HER穩定度，其質量活性及其在12小時的計時電流試驗後的衰退分別為9.56 A/mgPt 以及19 %，此結果說明Pd的添加以及類核/殼結構可以顯著的增加Pt基觸媒的穩定度。為了近一步提升觸媒的穩定度，本研究製備了三元PtPdM-NCs觸媒，其中又以PtPdNi-NCs具有最佳的穩定度，其質量活性在經過12小計時電流試驗後衰退12 %。;Pt and Pt-based nanoparticles (NPs) are wildly used as the electrocatalysts for the hydrogen evolution reaction (HER). However, the application of the Pt-based catalysts has the limitation due to its high cost and low utilization of Pt. Therefore, downsizing the catalysts is the key factor for the promotion of the HER performance. In order to solve those problem, in this study, carbon-supported Pt-nanoclusters (NCs), Pd-NCs, Pt-single atoms (SAs), Pd-SAs, PtxPdy-NCs (x/y= 1/2, 1/1, and 2/1), and PtPdM-NCs (M= Sn or Ni) are prepared by deposition-precipitation method. The electrochemical properties, morphologies (dark/ bright-fields), structures, surface compositions, chemical compositions and the microstructure of the catalysts are analyzed by rotating disc electrode (RDE), high angle annular dark-field scanning transmission electron microscopy (HAADF-STEM)/high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Inductively coupled plasma‒optical emission spectroscopy (ICP-OES), and X-ray absorption spectroscopy (XAS), respectively.
This study is divided into three parts. In the first part, Pt-NCs, Pd-NCs, Pt-SAs, and Pd-SAs are synthesized and their HER performance are compared with those of Pt-NPs and Pd-NPs. Pt-NCs and Pt-SAs exhibit the excellent HER performance with the mass activity at -0.05 V (MA0.05) of 1.3 and 10.6 A/mgPt, better than Pt-NPs (with MA0.05 of 0.3 A/mgPt) due to the small size and high Pt utilization. However, after chronoamperometry (CA) test for 12 hours, Pt-NCs and Pt-SAs show poor HER stability with the MA0.05 decay of 39 and 65 %, respectively.
In order to improve the HER stability, in the second part the bimetallic PtxPdy-NCs are prepared, and the PtPd-NCs exhibit the excellent HER performance with the MA0.05 and MA0.05 decay of 9.57 A/mgPt and 19 %, respectively, showing that the Pd addition can improve the HER stability.
In the third part, the PtPdM-NCs are prepared to further improve the HER stability, and the PtPdNi-NCs show the best HER stability with the MA0.05 decay of 12 %. |
