Deposition of transition metal or metal oxides on nanostructured metallurgical grade silicon by atomic layer deposition (ALD) for highly efficient photoelectrochemical water splitting

The goal of this project is to fabricate and optimize a photoelectrochemical (PEC) cell based on recently discovered nanostructured metallurgical grade silicon, which can be prepared by the metal assisted chemical etching process. In order to reduce the overpotential of the photoelectrode and to protect it against photoelectrochemical corrosion, transition metal or metal-oxide coatings, such as NiOx and CoOx, will be deposited on top of the as-prepared Si nanostructures by atomic layer deposition (ALD). The H2/O2 evolution efficiency of such a cost-effective system will then be assessed by in-depth photoelectrochemical and microstructural characterizations

Furthermore, we also investigate the preparation and electrocatalytic activity of several co-catalysts, which could be used to enhance the water splitting efficiency of our Si nanostructures, as well as that of the other photocatalytic nanostructures prepared in our group. An example of such a co-catalyst, is the heterostructure containing NiFe nanosheets (LDH = layered double hydroxide) on top of NiCoP nanowires on a nickel foam (NF) substrate. This heterostructure showed superior activity and electrochemical stability for both the H2 and the O2 evolution reaction (HER and OER), and was recently accepted for publication in Advanced Functional Materials [1].

[1] H. Zhang, X. Li, A. Hähnel, V. Naumann, C. Lin, S. Azimi, S.L. Schweizer, A.W. Maijenburg and R.B. Wehrspohn, Adv. Funct. Mater. 2018, 1706847.


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