Graphene–Noble Metal Nano-Composites and Applications for Hydrogen Sensors

Sukumar Basu,Surajit Hazra

doi:10.3390/c3040029

Abstract

Graphene based nano-composites are relatively new materials with excellent mechanical, electrical, electronic and chemical properties for applications in the fields of electrical and electronic devices, mechanical appliances and chemical gadgets. For all these applications, the structural features associated with chemical bonding that involve other components at the interface need in-depth investigation. Metals, polymers, inorganic fibers and other components improve the properties of graphene when they form a kind of composite structure in the nano-dimensions. Intensive investigations have been carried out globally in this area of research and development. In this article, some salient features of graphene–noble metal interactions and composite formation which improve hydrogen gas sensing properties—like higher and fast response, quick recovery, cross sensitivity, repeatability and long term stability of the sensor devices—are presented. Mostly noble metals are effective for enhancing the sensing performance of the graphene–metal hybrid sensors, due to their superior catalytic activities. The experimental evidence for atomic bonding between metal nano-structures and graphene has been reported in the literature and it is theoretically verified by density functional theory (DFT). Multilayer graphene influences gas sensing performance via intercalation of metal and non-metal atoms through atomic bonding.

Highlights

More research and development are being directed towards graphene based nano-composites
The chemical interaction between graphene and metal matrix at the interface of the composite is an interesting phenomenon, which is a valuable mechanism for interpreting the reinforcement of graphene–metal nano-composites
Novoselov and his co-workers [14] studied the distribution of metal nanoparticles in graphene–metal nano-composites by using High Resolution Transmission Electron Microscope (HRTEM)

Summary

Introduction

More research and development are being directed towards graphene based nano-composites. The chemical interaction between graphene and metal matrix at the interface of the composite is an interesting phenomenon, which is a valuable mechanism for interpreting the reinforcement of graphene–metal nano-composites. The bimetallic noble metals and graphene nano-composites have recently become a research interest [6, 7] because of their improved catalytic, optical and electronic properties [8]. The bimetallic noble metal nano-species, like Au–Pt, Pt–Pd, Pt–Ru, Au–Pd, Pt–Ag, Pd–Ag and Pd–Ru etc., are reported to have been deposited on the graphene surface [9]. These bimetallic nano-structures were prepared by one step in situ reduction of chloride salts and uniformly distributed on the graphene surface. Despite certain positive aspects of CVD methods, solution methods can be employed for large scale productions of graphene–metal nano-particle composites, using a cheap and simple procedure

Properties of Graphene–Noble Metal Nano-Composites

Bonding between Graphene and Noble Metals in the Nano-Composite Structure

Intercalation of Metals and Non-Metals in Graphene

Mechanism of Hydrogen Sensing by Graphene–Noble Metal Nanocomposites

Findings

Conclusions and Future Prospects