Room Temperature Operation of UV Photocatalytic Functionalized AlGaN/GaN Heterostructure Hydrogen Sensor

An AlGaN/GaN heterostructure based hydrogen sensor was fabricated using a dual catalyst layer with ZnO-nanoparticles (NPs) atop of Pd catalyst film. The ZnO-NPs were synthesized to have an average diameter of ~10 nm and spin coated on the Pd catalyst layer. Unlike the conventional catalytic reaction, the fabricated sensors exhibited room temperature operation without heating owing to the photocatalytic reaction of the ZnO-NPs with ultraviolet illumination at 280 nm. A sensing response of 25% was achieved for a hydrogen concentration of 4% at room temperature with fast response and recovery times; a response time of 8 s and a recovery time of 11 s.

A Supramolecular Porous Organic Cage Platform Promotes Electrochemical Hydrogen Evolution from Water Catalyzed by Cobalt Porphyrins

We report a supramolecular porous organic cage platform composed of cobalt porphyrins for catalyzing the electrochemical hydrogen evolution reaction (HER) from water at neutral pH. Owing to its permanent porosity, the supramolecular structure yields a catalyst film with a 5-fold increase in the number of electrochemically active cobalt atoms and an improvement in Tafel slope from 170 mV/decade to 119 mV/decade compared to a planar cobalt porphyrin analog, reaching activities over 19,000 turnovers for HER over a 24-hour period with 100% Faradaic efficiency.

A Supramolecular Porous Organic Cage Platform Promotes Electrochemical Hydrogen Evolution from Water Catalyzed by Cobalt Porphyrins

We report a supramolecular porous organic cage platform composed of cobalt porphyrins for catalyzing the electrochemical hydrogen evolution reaction (HER) from water at neutral pH. Owing to its permanent porosity, the supramolecular structure yields a catalyst film with a 5-fold increase in the number of electrochemically active cobalt atoms and an improvement in Tafel slope from 170 mV/decade to 119 mV/decade compared to a planar cobalt porphyrin analog, reaching activities over 19,000 turnovers for HER over a 24-hour period with 100% Faradaic efficiency.

Forming an Optically Transparent Graphene Film via the Transformation of C60 Molecules

This study aims to optimize the production conditions for forming graphene directly on a quartz substrate, using a carbon 60 (C60) thin film as a solid carbon source. In this experiment, we focused on the relationships between the thickness of the C60 film and the nickel (Ni) catalyst film and the heat treatment conditions. As the thicknesses of the C60 and Ni catalyst films increased, high-crystallinity multi-layered graphene was formed, however the optical transparency of the graphene film decreased. Scanning Electron Microscopy (SEM) observations and Raman scattering spectroscopy showed that after changing the atmosphere of the heat-treatment from an argon (Ar) gas to an Ar+ hydrogen (H2) gas, the optical transparency of the graphene film was remarkably improved, due to the migration and vaporization of the Ni film, and due to etching of the multi-layered graphene.