Large-scale synthesis of aligned carbon nanotubes was achieved by using a method based on chemical vapor deposition catalyzed by iron nanoparticles embedded in mesoporous silica. Scanning electron microscope images show that the nanotubes are approximately perpendicular to the surface of the silica and form an aligned array of isolated tubes with spacings between the tubes of about 100 nanometers. The tubes are up to about 50 micrometers long and well graphitized. The growth direction of the nanotubes may be controlled by the pores from which the nanotubes grow.

Coordinatively unsaturated Ni–N active sites facilitate CO2electroreduction and inhibit the competitive hydrogen evolution reaction, demonstrating selective and high-rate CO2electroreduction.

Au 25 and Pd 1 Au 24 clusters on multiwalled carbon nanotubes were developed via adsorption of Au 25 (SC 12 H 25 ) 18 and Pd 1 Au 24 (SC 12 H 25 ) 18 , respectively, on the nanotubes, followed by calcination. Comparison of their catalysis for the aerobic oxidation of benzyl alcohol showed that single Pd atom doping significantly improved the catalytic performance of Au 25 for the first time.

In this work, we synthesized gold clusters, Au n (n = 10, 18, 25, 39), with atomically controlled sizes on hydroxyapatite (HAP) and studied the catalysis for aerobic oxidation of cyclohexane. These Au n /HAP catalysts could efficiently oxidize cyclohexane to cyclohexanol and cyclohexanone. The turnover frequency monotonically increased with an increase in the size, reaching values as high as 18 500 h−1 Au atom−1 at n = 39, and thereafter decreased with a further increase in n up to n ∼ 85. This finding provides a fundamental insight into size-specific catalysis of gold in the cluster regime (diameter < 2 nm) and a guiding principle for rational design of Au cluster-based catalysts.