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CuO nanoparticles with controllable facets are of great significance for photocatalysis. In this work, the surface termination and facet orientation of CuO nanoparticles are accurately tuned by adjusting the amount of hydroxylamine hydrochloride and surfactant. It is found that CuO nanoparticles with Cu-terminated (110) or (111) surfaces show high photocatalytic activity, while other exposed facets show poor reactivity. Density functional theory simulations confirm that sodium dodecyl sulfate surfactant can lower the surface free energy of Cu-terminated surfaces, increase the density of exposed Cu atoms at the surfaces and thus benefit the photocatalytic activity. It also shows that the poor reactivity of the Cu-terminated CuO (100) surface is due to the high energy barrier of holes at the surface region.

SUMMARYThe cooperative output regulation of a linear multi‐agent system can be viewed as a generalization of the leader‐following consensus problem and was studied recently for the case where the system uncertain parameters vary in a sufficiently small neighborhood of their nominal value. This case was handled by the internal model design which converts the problem into a simultaneous eigenvalue placement problem of an augmented multi‐agent system. In this paper, we further consider the cooperative robust output regulation problem for a class of minimum phase linear multi‐agent systems in the sense that the controller allows the system uncertain parameters to vary in an arbitrarily prescribed compact subset. For this purpose, we introduce a new type of internal model that allows the cooperative robust output regulation problem of the given plant to be converted into a robust stabilization problem of an augmented multi‐agent system. We then solve our problem by combining a simultaneous high‐gain state feedback control technique and a distributed high‐gain observer technique. A special case of our result leads to the solution of the leader‐following robust consensus problem for a class of uncertain multi‐agent systems. Copyright © 2013 John Wiley & Sons, Ltd.