Advances in nanocatalysts for biofuel production: Mechanisms, performance, and future perspectives

The global pursuit of sustainable and low-carbon energy solutions has intensified research into biofuels as viable alternatives to fossil fuels. Yet, conventional catalytic processes often suffer from limitations such as low conversion efficiency, poor selectivity, and limited catalyst recyclability. Recent advances in nanotechnology have introduced nanocatalysts as powerful tools to overcome these barriers, owing to their high surface-to-volume ratio, tunable physicochemical properties, and superior catalytic performance. This review critically examines the application of nanocatalysts in major biofuel production routes, including transesterification, pyrolysis, hydrothermal liquefaction, hydrodeoxygenation, hydrolysis, fermentation, and steam reforming. The roles of metal and metal oxide nanoparticles, carbon-based nanomaterials, magnetic nanocomposites, zeolites, and bimetallic or multimetallic systems are comprehensively discussed in terms of catalytic mechanisms, yield enhancement, and reusability. The comparative advantages of nanocatalysts over traditional systems, particularly in reaction kinetics, thermal stability, and adaptability to diverse feedstocks, are emphasized. Furthermore, the review explores emerging strategies such as green synthesis methods, hybrid nanostructures, and integration into circular biorefinery platforms. Key challenges, including nanoparticle agglomeration, scalability, and long-term stability, are also outlined. By consolidating current advancements and identifying future research directions, this article highlights the transformative potential of nanocatalysts in improving biofuel productivity, process economics, and environmental sustainability, ultimately supporting the global transition toward renewable energy systems.