The present study aims to investigate the catalytic effect of a zinc sulfide-induced copper composite particles in ammonia decomposition and to analyze the energy and environmental metrics when combined with algae biodiesel blending. This study is the first attempt to employ composite particles as catalysts in order to expedite ammonia decomposition and reduce the energy required for activation in engine applications. Chlorella vulgaris algae were cultivated from treated effluent and converted into biodiesel, which was then blended with diesel at a 30 % volume and with aqueous ammonia at a 10 % volume. The test fuel's combustion performance and emission characteristics were assessed and revealed that Chlorella vulgaris biodiesel (CVB) blended diesel fuel reduces engine performance by 4.2–8.7 %. However, incorporating composite particles leads to improvements in performance parameters ranging from 6.5 % to 8.1 %. The utilisation of CVB blended fuel results in a 10.3 % rise in nitrogen oxides (NOx) emissions, accompanied by a decrease of 17.3 % in hydrocarbon (HC) emissions and a decrease of 11.2 % in carbon monoxide (CO) emissions. Introducing aqueous ammonia emulsion decreases NOx, HC, and CO emissions by 3.8 %, 16.9 %, and 14.1 %, respectively. When the composite material is combined with emulsion fuel, HC, CO, and NOx emissions are further reduced by 6.2 %, 14.5 %, and 13.1 %, respectively.