The fundamental understanding and rational manipulation of catalytic site preference at extended solid surfaces is crucial in the search for advanced catalysts.Herein we find that the Ru top sites at metallic ruthenium surface have efficient Ptlike activity for the hydrogen evolution reaction (HER), but they are subordinate to their adjacent, less active Ru 3 -hollow sites due to the stronger hydrogen-binding ability of the latter. We also present an interstitial incorporation strategy for the promotion of the Ru top sites from subordinate to dominant character,w hile maintaining Pt-like catalytic activity.O ur combined theoretical and experimental studies further identify intermetallic RuSi as ah ighly active,n on-Pt material for catalyzing the HER, because of its suitable electronic structure governed by ag ood balance of ligand and strain effects.

The martensitic transition, magnetocaloric effect (MCE) and shape memory effect (MSE) of ferromagnetic Heusler alloys Ni50Mn50−xSbx (x = 12, 13 and 14) have been investigated. A large positive magnetic entropy change ΔSM was observed in the vicinity of the martensitic transition. The maximum value of ΔSM is 9.1 J kg−1 K−1 in Ni50Mn37Sb13 at 287 K for a magnetic field change of 5 T. This change originates from the first-order transition from a low-temperature weak-magnetic martensitic phase to a high-temperature ferromagnetic parent phase. A magnetic-field-induced shape recovery strain of about 15 ppm at room temperature and at a relatively low magnetic field (1.2 T) was observed to accompany the reverse martensitic transformation. The large field-induced MCE and MSE in the NiMnSb system make it a promising material for room-temperature application.