## 3 Results and Discussions  
As explained in Section 2, ACRM was synthesized using a co-precipitation method. After synthesis, the calcined powder of ACRM was characterized using PXRD and SEM, and the characterization results were compared with pure CeO\({}_{2}\) material prepared using the co-precipitation method. Figure 4 compares the PXRD patterns of CeO\({}_{2}\) and ACRM. ACRM exhibits sharp crystalline peaks associated with a cubic fluorite crystal, similar to CeO\({}_{2}\), as seen in PXRD peaks. According to the PXRD patterns, there is no evidence of metallic Ag or Ag-oxide impurities, as no peaks are associated with them. Upon analyzing the zoomed section of the PXRD (20 = 28\({}^{\circ}\) to 30\({}^{\circ}\)), it has been observed that there is a noticeable shift in the peaks for the ACRM compared with the CeO\({}_{2}\) due to the structural strain [31]. It is a well-known fact that such peak shifts can generally be attributed to the replacement of the Ce\({}^{+4}\) cation by another metal cation. Therefore, based on the shift in the peaks recorded in Figure 4b, it can be inferred that the incorporation of Ag in the CeO\({}_{2}\) crystal structure has been successfully achieved, and the formation of ACRM has been accomplished via the co-precipitation method. The microstructural analysis of the ACRM synthesized through co-precipitation was examined using SEM. The SEM image in Figure 5a reveals that the particles exhibit a rough, spherical shape and appear agglomerated. The average particle size of the co-precipitation-synthesized ACRM was determined using ImageJ software (Version 1.54j). Figure 5b-e presents the particle size analysis across four distinct sections of the SEM image. Figure 4: (**a**) Wide angle PXRD patterns of the co-precipitation synthesized ACRM and CeO\({}_{2}\) and (**b**) shift in the peaks due to the incorporation of Ag in the CeO\({}_{2}\) crystal structure. The numbers on each image in Figure 5b-e indicate that the average particle size of the co-precipitation-synthesized ACRM falls within the 80 to 90 nm range. The accurate particle size range for co-precipitation synthesized ACRM was determined while avoiding particle agglomeration through TEM analysis. The TEM image in Figure 6 provided further insight and confirmed that the average particle size for co-precipitation synthesized ACRM falls within 25 to 30 nm. Discrepancies between the SEM and TEM analysis results arose from the sample preparation method employed for TEM analysis, which prevented particle agglomeration and allowed for observing individual particles rather than agglomerated ones. Figure 5: (**a**) SEM image of ACRM synthesized by using the co-precipitation method, (**b–e**) images obtained from the ImageJ software (particle size analysis). Figure 6: TEM image of ACRM synthesized by using the co-precipitation method. The ACRM powder, which was characterized, underwent a thermochemical CDS reaction test using a TGA setup. The Calisto software (Version 2.10), embedded in the TGA setup, was used to track the sample's mass variations during the TR and CDS stages. The procedure for conducting thermochemical redox reactions is explained in Section 2. Consecutively, several thermochemical redox cycles were carried out, employing thermal reduction at 1400 \({}^{\circ}\)C (60 min) and re-oxidation with CO\({}_{2}\) conversion into CO at 1000 \({}^{\circ}\)C (30 min). Blank TGA data were gathered under similar experimental conditions and utilized to subtract artifacts to eliminate the effect of buoyancy variation of gaseous components. One thermochemical cycle was performed to estimate the redox reactivity of co-precipitation synthesized ACRM in terms of mass loss or gain percentage during the TR and CDS steps. A TGA profile obtained for the cycle is presented in Figure 7. In this cycle, 101.95 mg of ACRM was loaded in the TGA. During the TR and CDS steps, 0.652 mg of mass loss and 0.201 mg of mass gain were recorded. The TGA plot confirms that the TR rate was slower than the CDS rate.