How Graphene is Produced from Palm Kernel Shell Waste

The Palm Oil Industry and Its Waste Challenge

Malaysia is the world's second largest producer of palm oil, with over 5.7 million hectares of oil palm plantations as of 2023. The industry generates enormous economic value but also produces millions of tonnes of solid biomass waste annually — including empty fruit bunches (EFB), palm kernel shell (PKS), and palm fibre.

Palm kernel shell, the hard woody shell surrounding the palm kernel seed, is generated at a rate of approximately 4–5 million tonnes per year in Malaysia alone. Traditionally, PKS has been used as a low-grade boiler fuel or landfilled. Its calorific value makes it suitable for burning, but this practice releases CO₂ and particulates. Converting PKS into high-value graphene materials represents a far more sustainable and economically beneficial alternative.

Why PKS is an Excellent Graphene Precursor

PKS has several properties that make it ideal as a graphene precursor:

• High carbon content (~50 wt%) compared to other biomass materials
• Low ash content and inorganic impurities relative to agricultural residues
• Consistent chemical composition due to standardised palm oil processing
• Abundant, renewable, and very low cost — essentially a waste material
• Readily available throughout Peninsular Malaysia year-round

Ecographe's Proprietary Production Process

Our end-to-end process converts raw PKS into Raman-verified reduced graphene oxide through four main stages:

Stage 1 — Biomass Pre-treatment and Carbonisation

Collected PKS is first cleaned, dried, and pre-treated to remove surface impurities and excess moisture. The PKS is then subjected to controlled pyrolysis (carbonisation) in an inert atmosphere at elevated temperatures. This step converts the organic material into a graphitic carbon structure, producing what is known as PKS-derived biochar or pre-graphite.

Stage 2 — Graphitisation

The carbonised PKS material undergoes further high-temperature graphitisation to increase the degree of graphitic ordering. X-ray diffraction (XRD) analysis of our intermediate material shows a clear graphitic (002) peak at approximately 26.5° 2θ, confirming the development of a well-ordered graphitic structure suitable for graphene oxide synthesis.

Stage 3 — Oxidation to Graphene Oxide

The PKS-derived graphite is chemically oxidised to graphene oxide using a modified Hummers-type method. Our proprietary modification reduces the use of hazardous reagents compared to the classical Hummers method while maintaining equivalent oxidation levels, verified by FTIR spectroscopy showing characteristic peaks for epoxide (~1050 cm⁻¹), hydroxyl (~3400 cm⁻¹), and carboxyl (~1720 cm⁻¹) functional groups.

Stage 4 — Chemical Reduction and Quality Verification

GO is chemically reduced to rGO using a proprietary reductant system. The reduction process is carefully optimised to maximise the G/D ratio on Raman spectroscopy — our target is consistently >1.5. Final product quality is confirmed using:

• Raman spectroscopy — G/D band ratio and 2D band analysis
• X-ray diffraction (XRD) — confirming restoration of graphitic d-spacing
• Elemental analysis — confirming >99% carbon, <5% oxygen
• BET surface area analysis — confirming 400–700 m²/g
• SEM/TEM imaging — confirming flake morphology and layer count