Cost effective hydrogen evolution reaction (HER) catalyst without using precious metallic elements is a crucial demand for environment-benign energy production. Molybdenum sulfide is one of the promising candidates for such purpose, particularly in acidic condition, but its catalytic performance is inherently limited by the sparse catalytic edge sites and poor electrical conductivity. We report synthesis and HER catalysis of hybrid catalysts composed of amorphous molybdenum sulfide (MoSx) layer directly bound at vertical N-doped carbon nanotube (NCNT) forest surface. Owing to the high wettability of N-doped graphitic surface and electrostatic attraction between thiomolybdate precursor anion and N-doped sites, ∼2 nm scale thick amorphous MoSx layers are specifically deposited at NCNT surface under low-temperature wet chemical process. The synergistic effect from the dense catalytic sites at amorphous MoSx surface and fluent charge transport along NCNT forest attains the excellent HER catalysis with onset overpotential as low as ∼75 mV and small potential of 110 mV for 10 mA/cm(2) current density, which is the highest HER activity of molybdenum sulfide-based catalyst ever reported thus far.

Outstanding pristine properties of carbon nanotubes and graphene have limited the scope for real-life applications without precise controllability of the material structures and properties. This invited article to celebrate the 25th anniversary of Advanced Materials reviews the current research status in the chemical modification/doping of carbon nanotubes and graphene and their relevant applications with optimized structures and properties. A broad aspect of specific correlations between chemical modification/doping schemes of the graphitic carbons with their novel tunable material properties is summarized. An overview of the practical benefits from chemical modification/doping, including the controllability of electronic energy level, charge carrier density, surface energy and surface reactivity for diverse advanced applications is presented, namely flexible electronics/optoelectronics, energy conversion/storage, nanocomposites, and environmental remediation, with a particular emphasis on their optimized interfacial structures and properties. Future research direction is also proposed to surpass existing technological bottlenecks and realize idealized graphitic carbon applications.

Porous zinc tin sulfide aerogel materials were constructed by metathesis reactions between Zn(acac) 2 3 H 2 O and tetrahedral thiostannate cluster salts containing discrete [SnS 4 ] 4-, [Sn 2 S 6 ] 4-, and [Sn 4 S 10 ] 4units. Self-assembly reactions of the Zn 2þ linker and anionic thiostannate clusters yielded polymeric random Zn/Sn/S networks with gelation properties. Supercritical drying of the gels and solvent/counterion removal resulted in a metal sulfur framework. Zn 2 Sn x S 2xþ2 (x = 1, 2, 4) aerogels showed high surface areas (363À520 m 2 /g) and pore volumes (1.1À1.5 cm 3 /g), and wide bandgap energies (2.8À3.2 eV). Scanning and transmission electron microscopy studies show the pores are micro-(d < 2 nm), meso-(2 nm < d < 50 nm), and macro-(d > 50 nm) regions. The zinc chalcogenide aerogels also possess high affinities toward soft heavy metals and reversible absorption of strong electron-accepting molecules.