Laser-Induced Hydrogen Generation from Methanol with Graphene Aerogel as the Target

Wieslaw Strek,Przemyslaw Wiewiórski,Taras Hanulia,Wlodzimierz Mista,Robert Tomala

doi:10.1021/acsomega.0c05238

Abstract

The present work demonstrates a new concept of the efficient generation of hydrogen from methanol by the continuous wave laser diode irradiation of an immersed graphene aerogel (GA) scaffold as the target. It was observed that the process occurred very intensively when it was assisted by bright white light emission in the spot of a laser-irradiated GA scaffold. The yield of hydrogen emission increased exponentially with the applied laser power. The light emission was assisted by the intense production of H2, CH4, and CO gases. It was found that with increasing excitation laser power, the H2 generation increased at the expense of CO. It is shown that the volume of CO decreases because of the formation of C2 molecules and CO2 gases. The mechanism of the laser-driven dissociation of methanol was discussed in terms of the violent ejection of hot electrons from the GA surface as a result of the laser-induced light emission of the graphene target.

Highlights

The seeking of new green energy sources is a subject of intense investigation
In the course of the experiment, it was observed that the sample of the graphene aerogel (GA) scaffold immersed in methanol emitted intense bright white light upon irradiation with the focused beam of infrared laser
The pyrolysis of methanol occurs in the temperature range of 1073−1223 K24 that is much higher than the temperature measured in the spot of irradiated graphene between 300 and 600 K;23 LI dissociation should be responsible for the observed bubble emission of gases

Summary

■ INTRODUCTION

The seeking of new green energy sources is a subject of intense investigation. In the face of climate change and increasing efficiency of renewable energy sources, the way to store it becomes a challenge. Studies of hydrogen generation from methanol were conducted through different reforming reactions, such as pyrolysis and catalytic techniques by using Pt, Pd, and Cu catalysts.[21] A noncatalytic reformation of methanol by using a microwave plasma reactor was described by Wang et al.[22] The purpose of these studies was the application of a focused beam of low-power CW infrared laser diodes (LD). The efficient production of hydrogen was assisted by LI white light emission from the surface of the graphene scaffold linked with the simultaneous ejection of photoelectrons responsible for methanol reformation This effect can be potentially applied for simultaneous generation of hydrogen from methanol by laser irradiation for injection into new types of methanol engines

■ RESULTS AND DISCUSSION

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES