PhotoElectroChemical applicCation of Uranium oxides for enhanced LIght AbsoRption (PECULIAR)

带隙能在2.0 ~ 2.6 eV范围内的铀氧化物具有良好的电学和催化性能，主要是由铀阳离子的易价动力学驱动的，是很有前途的光电化学水分解反应电极材料。虽然被认为是一种稀缺元素，但大量的贫铀源（例如，仅在美国就有70万吨UF6）最初是作为核燃料浓缩过程中的废物流产生的，目前由于意外释放挥发性、腐蚀性和有毒化合物而被储存起来，没有任何进一步应用的前景，对环境构成永久性危害。鉴于其有趣的电子和结构特性（贫）铀氧化物是能源应用的潜在有用材料，但由于可及性有限，迄今尚未探讨替代概念。首次实现了铀氧化物涂层气相沉积（热和等离子体辅助化学气相沉积）的铀金属有机前驱体，并研究了由此产生的薄膜作为水分解装置中潜在的光电极。申请人的初步研究表明，UOx在（照片）化学能转换循环中具有巨大且大部分未开发的潜力。铀氧化物是一种适用于PEC应用的半导体材料，因为它们的带隙能量意味着在太阳光谱可见部分的高光子吸收，更重要的是它们的能带边缘位置与氢和氧势跨越。提出的-奇特-将探讨不同的铀氧化物相和多晶在光电化学实验中的适用性。与众所周知的半导体金属氧化物（如TiO2， Fe2O3和ZnO）相比，铀氧化物的化学和材料方面的探索很少，因此这项工作将伴随着从头算DFT计算，以了解有关水分解反应的潜在过程。此外，U:O比对UOx与其他潜在光阳极材料的带隙能和热力学稳定性的影响将通过理论研究和实验验证进行研究。此外，杂质（掺杂剂）的影响以及与异质结构中已经存在的有效吸收剂的结合将被详细阐述，以详细了解光电催化性能并评估氧化铀从水中产生氢的有益使用。

Uranium oxides with band-gap energies in the range of 2.0 - 2.6 eV coupled with their good electrical and catalytic properties mostly driven by facile valence dynamics of the uranium cations are promising electrode materials in photoelectrochemical water splitting reactions. Although being considered a scarce element, huge amounts of depleted uranium sources (e.g.,alone 700,000 Tons UF6 in the USA) originally produced as waste streams in the enrichment process of nuclear fuels, is currently stored without any prospect for further applications that poses a perpetual environmental hazard, due to accidental release of volatile, corrosive and toxic compounds. In view of their interesting electronic and structural properties (depleted) uranium oxides are potentially useful materials for energy applications, however alternative concepts have been not probed so far due to the limited accessibility. For the first time uranium metal-organic precursors for the gas phase deposition (thermal and plasma-assisted chemical vapor deposition) of uranium oxide coatings have been achieved and the resulting thin-films have been investigated as potential photoelectrodes in water-splitting setups. Preliminary studies by the applicants illustrate the enormous and mostly unexplored potential of UOx in (photo)chemical energy conversion cycles. Uranium oxides are suitable semiconductor materials for PEC applications due to their band gap energies that imply high photon absorption in the visible part of the solar spectrum, and more importantly the fact that their band edge positions straddle with the hydrogen and oxygen potentials. The proposed - PECULIAR - will explore the suitability of different uranium oxide phases and polymorphs in photoelectrochemical experiments. Compared to well-known semiconductor metal oxides such as TiO2, Fe2O3 and ZnO, the chemistry and materials aspects of uranium oxides is scantily explored and therefore this effort will be accompanied by ab-initio DFT calculationsto understand the underlying processes with respect to water-splitting reactions . In addition, influence of U:O ratio on the band gap energies as well thermodynamical stability of UOx with other potential photoanode materials will be investigated by theoretical studies followed by their experimental validation. Further, the effect of impurities (dopants) and combination with already existing potent absorbers in heterostructures will be elaborated for a detailed understanding of the photoelectrocatalytical performance and the assessment of the beneficial use of uranium oxide to produce hydrogen from water.