Browsing by Author "Schipper, Desmond E"
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Item Thin Films of Metal Phosphides derived from Single-Source Organometallic Precursors for Advanced Materials Applications(2019-02-15) Schipper, Desmond E; Whitmire, Kenton HIn this thesis, organometallic complexes with main-group elements were used as single-source precursors (SSPs) to homometallic, heterobimetallic, and heterobimetallic/hetero-main group element transition metal pnictide (TMPn) thin films grown by metal-organic chemical vapor deposition (MOCVD) from synthesized SSPs and blends of SSPs. Films grown on conductive substrates were shown to be active electrocatalysts for water splitting catalysis while films grown on semiconducting substrates could be used to split water photoelectrocatalytically. Films of heterobimetallic transition metal phosphide FeMnP in its hexagonal phase were grown on a variety of substrates from SSP FeMn(CO)8(µ-PH2). It was also observed that films grown on quartz suffered from Mn oxidation due to non-innocent interaction with the substrate, which could be avoided by using alumina as a substrate owing to its relative inertness. Films of FeMnP grown on nickel foam and graphene-wrapped nickel foam were evaluated as water-splitting catalysts. The electrodes catalyzed both the hydrogen and oxygen evolution reactions at an ultra-low voltage of 1.51 V for 10 mA·cm-2 of current density and with stable performance. Films of FeMnP grown on an electrode consisting of a titanium dioxide nanorod array on fluorine-doped tin oxide achieved the theoretical photocurrent density for rutile TiO2 with high Faradaic efficiency for photoelectrochemical oxygen evolution and excellent stability. Additionally, electrodes were prepared by the SSP-MOCVD growth of FeP and Fe2P and compared to similarly prepared Fe3P. Evaluation of their catalytic activity towards the hydrogen evolution reaction showed activity to follow the trend Fe3P > Fe2P > FeP. Organometallic synthesis was directed at developing a precursor to (Fe1-xMnx)2(As,P) leading to the discovery of two suitable SSPs, {FeMn(CO)8}(µ4-As){Fe2(CO)7PtBuH2} and {FeMn(CO)8}(µ4-As){Fe2(CO)6(µ-CO)(µ-PtBuH)}, which were used to successfully grow (Fe1-xMnx)2(As,P) on quartz. 18 new organometallic clusters containing mixtures of Fe, Mn, As, and P were prepared and characterized en route to the ultimate SSPs.