Atomic Ag centers embedded in the surface of TiO2/SiO2 composite matrix as continuable photocatalysts for high decomposition of DMMP

Chemical warfare agents (CWAs) are a ubiquitous threat in the modern geopolitical landscape and pose enormous harm to human body and environment, which makes a great concern on the research of its degradation. Catalytic reaction is the simplest and most effective method of detoxification, which relies heavily on the catalyst. Compared with conventional nanoscale catalysts, single-atom catalysts exhibit better catalytic performance with higher catalytic activity and metal atom utilization efficiency. Herein, we report the enhanced photocatalytic decomposition of single-atom Ag-supported on the substrate composed of TiO 2 /SiO 2 , possessing both good photocatalytic properties and chemical stability. The results confirmed that Ag SA -TiO 2 /SiO 2 was developed by two steps of hydrolytic coprecipitation and reductive calcination. High-resolution microscopic morphology and spectroscopic tests indicated that Ag active sites are dispersed on the surface of the composite oxides in the form of atomic states. For the degradation performance, Ag SA -TiO 2 /SiO 2 demonstrated a promoted reduction of dimethyl methyl phosphate (DMMP) against the unloaded base materials, showing sustainable reusability and more than 5-fold lifetime extension. Moreover, theoretical calculations indicated that sufficient negative charge appeared on the surface of the SiO 2 platform, primarily localized on the Si and O atoms of the Ti—O—Si or Ag—O—Si configurations. The preferential adsorption on Si atoms avoided the affinity of adsorption molecules to degradation sites and reduced the contamination of these sites, meanwhile, Ag and Ti atoms showed the function to capture photons and transfer electrons. This study offers an approach to design well-defined and configurable Ag active sites on the surface of stable composite oxidative matrices for the remediation of DMMP-contaminated environments. • Ag was employed as the catalytically active sites highly dispersed on TiO 2 /SiO 2 composite. • SiO 2 acted as the supporting to intensify mechanical and photocatalytic properties of TiO 2 . • Ag SA -TiO 2 /SiO 2 demonstrated a promoted reduction of DMMP and sustainable reusability. • Si provided reaction platform, Ag/Ti tending to capture photons and transfer electrons.