A Simple “Nano-Templating” Method Using Zeolite Y Toward the Formation of Carbon Schwarzites

Schwarzites have a three-dimensional sp2 carbon structure with negative Gaussian curvatures. They can be synthesized through the deposition of carbon by chemical vapor deposition on a zeolite template and may be formed by increasing the amount of carbon. In this research, the amount of carbon deposition was increased by shortening the length of the diffusion pathways of the template through the use of nano-sized zeolite Y (nano-FAU). It was found that significantly larger quantities of carbon could be deposited inside the pores of nano-FAU (40 nm), compared to the micro-sized zeolite Y (300 nm). It is thus confirmed that by shortening the diffusion pathways enables more carbon to infiltrate into the center of the template before the pore channels are blocked, which leads to larger carbon depositions. A low acetylene gas concentration (15% vol in N2) and a prolonged period for chemical vapor deposition (6 h) is preferable for effectively loading carbon into the template. The obtained carbon replica exhibits the ordered structure derived from zeolite Y with an unprecedented 72 carbon atoms per supercage, of which a model with a structure similar to schwarzite was proposed.This work was supported by Grant-in-Aid for Scientific Research (A), 17H01042 (HN); the Nano-Macro Materials, Devices and System Research Alliance; and the Network Joint Research Center for Materials and Devices. The support from Sirindhorn International Institute of Technology under the Excellent Thai Student Program (PB) and from the Research Grant for New Scholar (Grant No. MRG6080153) co-funded by the Thailand Research Fund (TRF); the commission on Higher Education, Thailand; and Thammasat University, are also acknowledged

Orientation Control of <i>Trametes</i> Laccases on a Carbon Electrode Surface to Understand the Orientation Effect on the Electrocatalytic Activity

By using a carbon-coated anodic aluminum oxide (CAAO) film as a monolithic porous electrode for the immobilization of <i>Trametes</i> laccases (LACs), an attempt is made to control the orientation of LAC molecules toward the electrode surface simply by applying an electric potential to the CAAO film. Because the resulting film is characterized by a myriad of open, simple, and straight nanochannels with diameters as large as 40 nm, the O₂ diffusion problem in pores is minimized, thereby making it possible to highlight the effect of such orientation on the electrocatalytic activity as a biocathode. It has been evidenced that LAC molecules are favorably oriented for a smooth electron transfer from the electrode when the LACs are immobilized with applying a positive voltage to the electrode, and such favorable orientation exhibits 3.7-times higher electrocatalytic activity than unfavorable orientation. Furthermore, the orientation mechanism has been rationally explained in terms of local surface chemistry on a LAC molecule