## 4 Conclusions  
We demonstrated that porous SiC and SiC/C\({}_{\text{f}}\) ceramic microspheres can be obtained by a simple and inexpensive method from PHMS cross-linked with DVB polysiloxane microspheres. The polysiloxane microspheres were converted to the ceramic material by pyrolysis under conditions where thermal reduction removes oxygen from the ceramics. The weight ratio of DVB to PHMS used in the synthesis of preceramic particles controls the final composition of the ceramic microspheres. Ceramization of the siloxane microspheres obtained at a DVB/PHMS weight about a ratio higher than 0.5 leads to SiC material containing free sp\({}^{2}\) carbon SiC/C\({}_{\text{f}}\). SiC microspheres without C\({}_{\text{f}}\) are obtained at the DVB/PHMS weight ratio of less than 0.5, but at the expense of ceramic yields. In this case, some oxygen remains after all C\({}_{\text{f}}\) has been used up in the carbothermal reduction process. This oxygen is mainly removed as gaseous SiO formed by the reaction of SiO\({}_{2}\) with SiC, which reduces the yield of ceramics. The thermal reduction process causes the formation of porosity in the ceramic microspheres, the nature of which depends on the content of the cross-linking agent in the preceramic particles. The SiC/C\({}_{\text{f}}\) micro/mesoporous material is produced from siloxane particles obtained at a higher DVB/PHMS weight ratio. On the other hand, hierarchical macro/mesoporosity is generated in SiC microspheres obtained from siloxane microspheres obtained with a lower DVB content. The ceramic SiC phase mostly has a \(\beta\)-SiC crystalline structure, while the free carbon phase is in the form of a disordered graphitic structure. **Supplementary Materials:** The following are available online at [[https://www.mdpicom/article/10.3390/ma15010081/s1](https://www.mdpicom/article/10.3390/ma15010081/s1)]([https://www.mdpicom/article/10.3390/ma15010081/s1](https://www.mdpicom/article/10.3390/ma15010081/s1)), Figure S1: Micrographs of preceramic siloxane microspheres obtained at different DVB/SiH weight ratio: (**a**) PA-1, (**b**) PA-3, (**c**) PB-1, (**d**) PA-6, Figure S2. Distribution of sizes of preceramic siloxane microspheres: (**a**)--PA-1, (**b**)--PA-3, (**c**)--PB-1, (**d**)--PA-6, Figure S3. Example of SEM/EDS spectrum of ceramic microspheres: sample A-6, Figure S4. Example of Raman spectrum of the SiC/C\({}_{\text{f}}\) ceramic microspheres--sample A-5 DVB/HMPS \(w/w\) = 0.80, the resolution of the overlapping bands was made using Gaussian-Lorentzial approach, Figure S5. Cumulative plots of the distribution of pore width: (**a**) by pore volume, (**b**) by pore surface, Figure S6. \({}^{29}\)Si MAS NMR spectrum of ceramic microspheres A-7 after heating in air at 800 \({}^{\circ}\)C for 3 h, Table S1: Spectroscopic characterization of the preceramic microspheres obtained by homogenization at 7500 rpm for 90 s, Table S2. Elemental composition of the ceramic microspheres determined by SEM/EDS. **Author Contributions:** Conceptualization, J.C., S.R. and U.M. ; methodology, J.C. and U.M. ; synthesis, U.M. and W.F. ; acquisition of data, J.Z., W.F., A.N.-M. and I.B.-S.; analysis, W.F., J.Z., A.N.-M. and I.B.-S.; interpretation of data, J.C., S.R. and U.M. ; writing--original draft preparation, J.C. and S.R. ; writing--review and editing, U.M. ; supervision, S.R. ; project administration, U.M. ; funding acquisition, U.M. ; All authors have read and agreed to the published version of the manuscript. **Funding:** The financial support from NCN grant 2019/03/X/ST5/00182 is highly appreciated. N\({}_{2}\) adsorption-desorption experiments were performed on the apparatus ASAP 2020 Plus (Micrometrics) purchased under the Regional Operational Program for the Lodz region, RPLD.01.01.00-10-0008/18. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement**: Not applicable.