Graphene for a Sustainable Future: Clean Energy, Environmental Remediation, and Green Pathways a Review

Graphene is a two-dimensional carbon nanomaterial whose exceptional properties high mechanical strength (Young's modulus ∼1 TPa; tensile strength >130 GPa), high carrier mobility (>200,000 cm2/V· s at room temperature), high thermal conductivity (∼5,000 W/m· K), and large theoretical specific surface area (∼2,630 m2/g) make it an attractive platform for sustainability-oriented technologies. In this review, we will critically discuss green and sustainable synthesis routes such as those derived from biomass/waste materials, electrochemical exfoliation, and green chemical vapor deposition innovations, and their associated sustainability based on life cycle assessment concepts, functional units, and impact category indicators such as energy consumption and greenhouse gas emissions. Next, we will discuss the role of graphene in green energy conversion and storage devices such as solar cells, batteries/supercapacitors, and hydrogen fuel cells, and green environmental remediation techniques such as water purification/desalination, air filtration/gas separation, and environmental catalysis. Finally, we will discuss general issues that may impact the sustainable use of graphene, including scalability and cost, variability in material composition, potential environmental release and toxicity, and standardization issues. Graphene has significant potential to contribute to green energy and environmental applications when considering low impact synthesis routes, performance-adjusted life cycle assessments, and green product life cycles rather than assuming green by default.