Bifunctional earth-abundant phosphate/phosphide catalysts prepared via atomic layer deposition for electrocatalytic water splitting

The development of active and stable earth-abundant catalysts for hydrogen and oxygen evolution is one of the requirements for successful production of solar fuels. Atomic Layer Deposition (ALD) is a proven technique for conformal coating of structured (photo)electrode surfaces with such electrocatalyst materials. Here, we show that ALD can be used for the deposition of iron and cobalt phosphate electrocatalysts. A PE-ALD process was developed to obtain cobalt phosphate films without the need for a phosphidation step. The cobalt phosphate material acts as a bifunctional catalyst, able to also perform hydrogen evolution after either a thermal or electrochemical reduction step

Atomic layer deposition of nanoalloys of noble and non-noble metals

We present a novel ALD-based approach for the synthesis of bimetallic materials consisting of a noble metal along with a nonnoble metal such as Pt-M (M = In, Ga, Sn, etc.), with a precise control on the composition and size. First, a bilayer consisting of a metal oxide and a Pt film of the desired thickness is deposited on to the substrate. The film is then subjected to a temperature programmed reduction (TPR) under H2 atmosphere. In situ X-ray diffraction (XRD) measurements during TPR revealed the formation of Pt±M bimetallic alloys with a phase determined by the Pt/(Pt + M) atomic ratio of the as-deposited bilayer. Scanning electron microscopic (SEM) analysis revealed the formation nanoparticles after annealing, with the particle size controlled by the initial total thickness of the bilayer

Mobile setup for synchrotron based in situ characterization during thermal and plasma-enhanced atomic layer deposition

We report the design of a mobile setup for synchrotron based in situ studies during atomic layer processing. The system was designed to facilitate in situ grazing incidence small angle x-ray scattering (GISAXS), x-ray fluorescence (XRF), and x-ray absorption spectroscopy measurements at synchrotron facilities. The setup consists of a compact high vacuum pump-type reactor for atomic layer deposition (ALD). The presence of a remote radio frequency plasma source enables in situ experiments during both thermal as well as plasma-enhanced ALD. The system has been successfully installed at different beam line end stations at the European Synchrotron Radiation Facility and SOLEIL synchrotrons. Examples are discussed of in situ GISAXS and XRF measurements during thermal and plasma-enhanced ALD growth of ruthenium from RuO4 (ToRuS™, Air Liquide) and H2 or H2 plasma, providing insights in the nucleation behavior of these processes