Lawley Craig, Nachtegaal Maarten, Stahn Jochen, Roddatis Vladimir, Döbeli Max, Schmidt Thomas J, Pergolesi Daniele, Lippert Thomas
Paul Scherrer Institute, Forschungsstrasse 111, 5232, Villigen PSI, Switzerland.
Department of Chemistry and Applied Biosciences, ETH Zürich, 8093, Zürich, Switzerland.
Nat Commun. 2020 Apr 7;11(1):1728. doi: 10.1038/s41467-020-15519-y.
LaTiON oxynitride thin films are employed to study the surface modifications at the solid-liquid interface that occur during photoelectrocatalytic water splitting. Neutron reflectometry and grazing incidence x-ray absorption spectroscopy were utilised to distinguish between the surface and bulk signals, with a surface sensitivity of 3 nm. Here we show, contrary to what is typically assumed, that the A cations are active sites that undergo oxidation at the surface as a consequence of the water splitting process. Whereas, the B cations undergo local disordering with the valence state remaining unchanged. This surface modification reduces the overall water splitting efficiency, but is suppressed when the oxynitride thin films are decorated with a co-catalyst. With this example we present the possibilities of surface sensitive studies using techniques capable of operando measurements in water, opening up new opportunities for applications to other materials and for surface sensitive, operando studies of the water splitting process.
采用氮氧化镧钛薄膜研究光电催化水分解过程中固液界面发生的表面改性。利用中子反射仪和掠入射X射线吸收光谱来区分表面和体相信号，表面灵敏度为3纳米。我们在此表明，与通常的假设相反，A阳离子是由于水分解过程而在表面发生氧化的活性位点。而B阳离子发生局部无序化，价态保持不变。这种表面改性降低了整体水分解效率，但当氮氧化物薄膜用助催化剂修饰时，这种改性会受到抑制。通过这个例子，我们展示了使用能够在水中进行原位测量的技术进行表面敏感研究的可能性，为应用于其他材料以及对水分解过程进行表面敏感的原位研究开辟了新的机会。
