The ERC ReSuNiCo project with core objectives including (1) single droplet reactors and precursor design for sulfides and (2) analysis of the burning droplets, mass transfer, reaction and particle formation was kicked off on January 2019. These objectives are investigated by one PhD student (Ms. Adithya Balakrishnan hired in May 2019) working on the precursor-solvent screening for droplet combustion and the other (Mr. Jan Derk Groeneveld, hired in September 2019) on optical diagnostics of the burning droplets. Mr. Jan Treumann, third PhD student was hired in October 2020 for the execution of the task “Process models and reactor design rules” in WP3. Despite the delays in the experimental set-up (due to pandemic), the work was focused on designing the single droplet reactor, alternative approach for precursor chemistry. While extensive chemical/ laboratory safety, risk protocol and experiments involving H2S were not possible, an alternative pathway to sulphur based precursor-solvent combinations was considered. The highly combustible and exothermic precursor-solvents (from Zn, Cu and Fe precursors) allowed multiple -explosions in the gas phase resulting to crystalline and ultrafine metal sulphide nanoparticles (2-5 nm). While the combustion experiments were performed with the precursor-solvent combinations with inherent S-source, the tasks are in very good alignment with the objectives. From August 2021, the laboratory is operational with H2S gas where all the necessary knowledge of precursor-solvent combustion in such gas atmosphere have been known. In addition, the prototype of the single droplet combustion generator was designed, developed, manufactured and tested in a separate laboratory in presence of O2 atmosphere. While designing the single droplet generator and its components took more time than expected, the prototype is now functional. The single droplet combustion results using sulphide-based precursor and/or solvents was a key for in-depth understanding the combustion behaviour in H2S gas atmosphere. For the alternative chemical reaction, two liquid precursors-one involving metal source and the other with sulfur source were mixed together to obtain precipitation/colloidal free solutions. These precursor-solvent were then screened for the metal sulfide formation. This is in line with the DoA where our work package is based on screening such precursor-solvent combination. Such alternative chemical reaction supports the overall knowledge that we plan to acquire with the reaction using H2S gas. The resources of ReSuNiCo project were largely dedicated to safety installation, laboratory set-up, prototype building, preliminary precursor-solvent combination screening and single droplet combustion to determine droplet reaction and schemes, -explosion kinetics and particle formation. While all the installations are now completed, and that the single droplet reactor is operational, the tasks specified in the work packages will be executed smoothly and rapidly. Although there were problems along the way, we did test the hypotheses and the corresponding objectives were achieved.