Nickel-rich NiCeLaFeCo medium-entropy alloy nanoparticles on oxygen and nitrogen co-doped carbon supports for hydrogen production from toluene cracking

•Medium-entropy alloy (MEA) nanoparticles on carbon substrates were obtained.•The nickel-rich MEA nanoparticles were exhibited small particle sizes.•The NiCeLaFeCo catalysts had an excellent performance for toluene cracking.•The MEA catalysts had higher toluene conversion and hydrogen generation.•Steam reforming prevented coke deposition and improved the H2 yield and stability. [Display omitted] Multi-metallic nanoparticles (MMNPs) attract people’s attention due to their great potential in the application of energy storage, medicine, and catalysis. In this study, a simple in situ reduction method was developed to synthesize the NiCeLaFeCo and NiCeLaFeCu medium-entropy alloy (MEA) nanoparticles on nitrogen and oxygen co-doped carbon supports, with guanine and transition metal nitrates as the precursors. The prepared face-centered cubic (FCC) NiCeLaFeCo MEA nanoparticles have small particle sizes (average 21.1 nm) and medium mixing entropy (1.31 R). To extend the application of MEA nanoparticles, we have conducted a toluene cracking test regarding toluene conversion and hydrogen generation. The catalyst loaded with nickel-rich (~55.26%) MEA nanoparticles presented a high catalytic performance (over 80% conversion and 7293 ppm hydrogen generation) at 500 °C upon 2 h time-on-stream, and better catalytic performance (99% conversion and 78960 ppm hydrogen generation) at 400 °C with steam reforming. This study has provided a simple and convenient way to synthesize the functionalized carbon-based multi-metallic nanoparticles, and showed their excellent catalytic performance in the toluene cracking and hydrogen generation.