What is the most significant result of this study? In this work, atomic layer deposition (ALD) was applied to deposit ultrathin Al 2 O 3 coats on Pt nanoparticles that are confined in Al 2 O 3 nanotubes. This catalyst was elaborately designed to maximize the metal oxide interfaces and exhibited the maximized catalytic activity compared with the conventional confined catalysts and/or supported catalysts. We believe that applying ALD ultrathin coats on confined catalysts is ap romising way to achieve enhanced performance for other catalysts. What prompted you to investigate this topic/problem? Metal-support interfaces play ap rominent role in heterogeneous catalysis. However,t ailoring the metal-support interfaces to realize full utilization remains am ajor challenge. Our previous work has demonstrated that metal nanoparticles not only confined in the nanotubes but also embedded in the internal wall have increased interfacial sites compared with the same metal nanoparticles supported on the outside of the nanotubes. This result prompted us to further modify the confined catalysts for the increased interfaces. Therefore, we attempt to coat the confined catalysts with an ultrathin coating to maximize the metal-support interfaces. What was the biggest surprise? In the course of the study,w es urprisingly found that the ALD cycle number of ultrathin coats has ah uge effect on the hydroge-nation activity.T he catalyst with two cycles Al 2 O 3 coatings showed significantly higher activity (about five times) than that of the un-coated catalyst. However,a fter further depositing only three cycles of Al 2 O 3 coatings ,t he activity of the catalyst sharply decreased to 1:10 of the uncoated catalyst. This result indicates that the metal-support interfaces have as trong effect on the performance of the catalyst and that ap recise and optimal cycle numbers for ALD Al 2 O 3 is necessary for the maximized interfaces. What future opportunities do you see (in the light of the results presented in this paper)? The method of coating the confined catalysts can be extended to other catalytic systems in which the metal-support interfaces have astrong effect on the catalytic performance. Invited for the cover of this issue is the group of Yong Qin at the Chinese Academy of Sciences. The image depicts the main features of the designed catalyst, whicha re the Al 2 O 3 nanotubes, confined Pt nanoparticles, and ultrathin Al 2 O 3 coats. Read the full textoft he article at