Graphene as a thin-film catalyst booster: graphene-catalyst interface plays a critical role

Abstract

Due to its extreme thinness, graphene can transmit some surface properties of its underlying substrate, a phenomenon referred to as graphene transparency. Here we demonstrate the application of the transparency of graphene as a protector of thin-film catalysts and a booster of their catalytic efficiency. The photocatalytic degradation of dye molecules by ZnO thin films was chosen as a model system. A ZnO thin film coated with monolayer graphene showed greater catalytic efficiency and long-term stability than did bare ZnO. Interestingly, we found the catalytic efficiency of the graphene-coated ZnO thin film to depend critically on the nature of the bottom ZnO layer; graphene transferred to a relatively rough, sputter-coated ZnO thin film showed rather poor catalytic degradation of the dye molecules while a smooth sol-gel-synthesized ZnO covered with monolayer graphene showed enhanced catalytic degradation. Based on a systematic investigation of the interface between graphene and ZnO thin films, we concluded the transparency of graphene to be critically dependent on its interface with a supporting substrate. Graphene supported on an atomically flat substrate was found to efficiently transmit the properties of the substrate, but graphene suspended on a substrate with a rough nanoscale topography was completely opaque to the substrate properties. Our experimental observations revealed the morphology of the substrate to be a key factor affecting the transparency of graphene, and should be taken into account in order to optimally apply graphene as a protector of catalytic thin films and a booster of their catalysis.

Graphene-supported single-atom catalysts and applications in electrocatalysis

“…Graphene, the building block of the carbon allotrope family, featuring a single layer of sp 2 hybridized carbon atoms, has been intensively investigated during the last decade. The excellent electronic properties, including the highest electronic mobility and conductivity, promise its potential application in electrocatalysis [34,35]. However, the zero-overlap semimetal of intrinsic graphene leads to poor catalytic activity, owing to the limited population of catalytic sites.…”

Two-dimensional forms of robust CO2 reduction photocatalysts

“…Two-dimensional (2D) systems, characterized by a layered crystalline structure, offer a less well-studied and highly tunable avenue for future PECs 17,18 . The surprising effects of two-dimensional material interactions, such as ZnS/PbO and ZnSe/PbO heterostructures exhibiting enhanced solar absorption 19 , expands the space of possible 2D-material based reactors even further beyond monolayers to the massive combinatoric space of heterostructures and 2D material coatings 17,20,21 .…”

Nanoscale layer of a minimized defect area of graphene and hexagonal boron nitride on copper for excellent anti-corrosion activity

“…catalytic properties [6][7][8]. Graphene, a 2D ultra-thick, planar structure of carbon atoms configured in a honeycomb crystal lattice, has attracted significant interest owing to its excellent mechanical, electrical, and optical properties [9,10].…”