Nanoparticle additives for improving pyrolysis oil–diesel fuel blends

Pyrolysis oil (PO), which is derived from the thermochemical conversion of waste, is a promising low-carbon fuel with the potential to at least partially substitute petroleum-based diesel. However, the direct utilization of PO in engines presents several challenges, including compositional heterogeneity, suboptimal engine efficiency, and economic constraints. The addition of nanoparticles (NPs) has emerged as a strategy for enhancing fuel properties, improving combustion performance, and mitigating exhaust emissions. Recent studies have investigated integrated NPs into PO–diesel blends to enhance engine compatibility and environmental performance. This review summarizes the current advances in NP synthesis and evaluates physicochemical characteristics and engine performance of PO-based nanofuels. Adding NPs to PO–diesel blends can increase brake thermal efficiency (BTE) and decrease brake-specific fuel consumption (BSFC), which extents depending on the type of NPs. CuO and graphene oxide NPs are found to be advantageous to improving overall fuel performance. Moreover, the key priorities for future research include reducing production costs, improving the compositional uniformity of PO, and evaluating the environmental and health effects associated with NP use.