The growing demand for clean energy and sustainable technologies has intensified the need for efficient energy storage systems (EES) that support renewable energy integration while minimizing environmental impact. Biomass, an abundant and renewable resource, presents a cost-effective and eco-friendly pathway for producing advanced carbon materials, particularly heteroatom-doped graphene derivatives. This transformation aligns with circular economy principles by converting waste streams into high-performance materials for EES applications. This review provides a comprehensive analysis of biomassderived heteroatom-doped graphene materials, focusing on their synthesis, properties, and applications in electrochemical energy storage systems. It addresses a critical gap in the literature by systematically examining the relationship between biomass sources, doping strategies, and their impact on graphene’s electrochemical performance. The study highlights the role of heteroatom doping such as nitrogen, sulfur, phosphorus, and boron in enhancing graphene’s structural and electronic properties. These modifications introduce active sites, improve conductivity, and facilitate ion storage and transport, resulting in superior energy density, cycling stability, and charge–discharge performance in devices such as sodium/lithium-ion batteries, lithium-sulfur batteries, supercapacitors, and fuel cells. Recent advancements in green synthesis methods, including pyrolysis, hydrothermal carbonization, and chemical activation, are highlighted, focusing on their scalability and resource efficiency. By addressing both environmental and technological benefits, this review bridges the gap between laboratory research and practical applications. It underscores the critical role of biomass-derived graphene in achieving sustainable energy solutions and advancing the circular economy, offering a roadmap for future innovations in this rapidly evolving field.

Environmental pollution has become an alarming issue for the modern world due to the extensive release of untreated chemical waste into freshwater bodies. Untreated chemical waste poses significant negative impacts on aquatic life and human health. The phenolic compounds are widely used in different industries for dyeing, as food preservatives, and for the production of pesticides. 2,4,6-Trichlorophenol (TCP) is among the most hazardous phenolic compounds that cause several serious health effects. Thus, it is important to monitor TCP in the environmental samples frequently. In the current work, it was aimed to develop a highly sensitive zinc oxide-doped (ZnO) reduce graphene oxide (rGO) composite-based electrochemical sensor for TCP monitoring in the real samples. In this regard, graphene oxide (GO) was simultaneously reduced and doped with ZnO using a facile microwave-assisted synthesis strategy. The resulting ZnO/rGO composite was successfully utilized to fabricate ZnO/rGO-modified glassy carbon electrode (ZnO/rGO/GCE) for the selective and trace level determination of TCP. The conductivity and electrocatalytic behaviors of ZnO/rGO/GCE were examined through different modes of electrochemical setup. Under the optimal operating conditions such as a scan rate of 80 mV.s−1, PBS electrolyte (pH 7.0), and the concentration range of 0.01–80 μM, the fabricated electrochemical sensor manifested outstanding responses for monitoring TCP. The limit of detection (LOD) and limit of quantification (LOQ) of the ZnO/rGO/GCE for TCP were found as 0.0067 μM and 0.019 μM, respectively. Moreover, the anti-interference profile and stable nature of ZnO/rGO/GCE made the suggested electrochemical sensor a superb tool for quantifying TCP in a real matrix.