Study of Ag/MO ₂ (M═Ce, Zr, Sn, and Ti) Nanomaterials Synthesized via Surfactant‐Free One‐Pot Hydrothermal Method for CO Oxidation

Abstract In this study, Ag/MO 2 (M═Ce, Zr, Sn, and Ti) nanomaterials were synthesized via a surfactant‐free one‐step hydrothermal process followed by calcination at 500 °C for 5 h and investigated the impact of different metal oxides on Ag‐based nanomaterials as catalysts for CO oxidation. Comprehensive characterization analysis using various techniques including XRD, BET, FE‐SEM with EDS and elemental mapping, TEM, HR‐TEM with SAED and XPS, provided insights into the physicochemical properties of the Ag/MO 2 nanomaterials. Depending on the variation in the redox (Ag/CeO 2 and Ag/TiO 2 ) and nonredox (Ag/ZrO 2 and Ag/SnO 2 ) nature of metal oxides, Ag metallic state, crystallite sizes, surface area, morphology, and adsorbed surface oxygen are affected. The catalytic activity towards the CO oxidation was in the order: Ag/CeO 2 > Ag/ZrO 2 > Ag/TiO 2 >> Ag/SnO 2 . This enhanced performance can be attributed to the presence of metallic Ag, abundant surface oxygen (46.46%), improved interaction between metallic Ag and CeO 2 due to rice‐ball structure. Ag/CeO 2 exhibited better catalytic activity even after 3 consecutive cycles toward CO oxidation (T 50% = 150 °C). This resilience can be linked to the stable spherical morphology and intact rice‐ball structure. The findings demonstrate the impact of metal oxides on Ag‐based nanomaterials physicochemical properties and thus CO oxidation activity.