Comparative study of different functionalized graphene-nanoplatelet aqueous nanofluids for solar energy applications

TL;DR

This study compares the optical properties of two types of functionalized graphene nanoplatelet nanofluids in water, highlighting their potential for solar energy applications due to high light extinction and non-linear optical behavior.

Contribution

It provides a comparative analysis of chemically modified graphene nanofluids' optical properties, focusing on their stability and non-linear behavior under high solar intensities.

Findings

Nanofluids showed high light extinction coefficients.

They exhibited non-linear optical behavior under high light intensities.

Moderate stability was achieved in the nanofluids.

Abstract

The optical properties of nanofluids are peculiar and interesting for a variety of applications. Among them, the high light extinction coefficient of nanofluids can be useful in linear parabolic concentrating solar systems, while their properties under high light irradiation intensities can be exploited for direct solar steam generation. The optical characterization of colloids, including the study of non-linear optical properties, is thus a needed step to design the use of such novel materials for solar energy exploitation. In this work, we analysed two different types of nanofluids, consisting of polycarboxylate chemically modified graphene nanoplatelets (P-GnP) and sulfonic acid-functionalized graphene nanoplatelets (S-GnP) dispersed in water, at three concentrations from 0.005 wt% to 0.05 wt%. Moderately stable nanofluids were achieved with favourable light extinction properties, as well as a non-linear optical behaviour under high input solar intensities.