A study led by Rocco Cancelliere and colleagues, published in the Journal of Environmental Chemical Engineering, examines how pyrolysis conditionsThe conditions under which pyrolysis takes place, such as temperature, heating rate, and residence time, can significantly affect the properties of the biochar produced.   More affect the surface morphology and electrochemical properties of biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More. Using hazelnut shells (HZS) and spent coffee grounds (SCG) as feedstocks, the researchers evaluated biochar performance as a sensor material for screen-printed electrodes (SPEs).

The team produced biochar at 450°C and 550°C, with additional thermal post-treatments of 10 or 60 minutes. Key findings reveal that biochar from hazelnut shells processed at 550°C (HZS_550) showed superior electrochemical performance, achieving a 1.5-fold increase in electron transfer efficiency and a 2-fold increase in diffusivity compared to SCG-derived biochar. This enhanced performance is attributed to HZS_550’s homogeneous and porous microstructure, which facilitates better conductivity and sensor responsiveness.

Further analysis demonstrated that higher pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More temperatures promote the development of graphite-like structures, increasing biochar’s electron transport capacity. However, post-production thermal treatments had negligible impact on conductivity, reinforcing the primary importance of initial pyrolysis conditions.

The HZS_550-modified electrodes excelled in detecting redox-active probes, achieving detection limits in the micromolar range and halving those of unmodified electrodes. These results underscore biochar’s potential as a sustainable, high-performance material for electrochemical sensing applications.

This work highlights the importance of optimizing pyrolysis conditions to maximize biochar’s functional properties, offering insights for advancing biochar-based technologies in sensing and beyond.

SOURCE: Cancelliere, et al (2025) Mutual interaction of pyrolysis operating conditions and surface morphology for the electrochemical performance of biochar-modified screen-printed electrodes. Journal of Environmental Chemical Engineering. https://doi.org/10.1016/j.jece.2025.115477