In-situ synthesis of well-dispersed Cu/Cu2O nanoparticles supported on petaloid SiO2 for efficient degradation of high concentration tetracycline hydrochloride

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Low-valent transition metal catalysts have shown great application potential in boosting the Fenton-like catalytic performance. The dispersity and particle size are closely related to catalytic performance. However, it is still a challenge to develop a simple and effective strategy to synthesize well-dispersed low-valent transition metal catalysts with small particle size. Herein, Cu/Cu2O nanoparticles with the size of about 42 nm are successfully in-situ synthesized during the carbonization process of surfactants, and evenly dispersed on petaloid SiO2 (x-CS catalysts). The ratio of Cu/Cu2O can be easily adjusted by changing the adding amount of Cu(NO3)2. 6-CS catalyst exhibits the optimal catalytic performance for the degradation of high concentration tetracycline hydrochloride (TC, 100 mg/L). About 89.4 % of TC is degraded within 40 min of reaction. The excellent catalytic ability is mainly attributed to the plenty of exposed highly reactive metal sites, accelerating the activation of H2O2. The experimental results show that Cu species are the catalytic active centers, in which low-valent Cu(0)/Cu(Ⅰ) plays the critical role in boosting the catalytic performance. Interestingly, the leaching concentration of Cu ions in solution is reduced to some extent, which is attributed to the adsorption by functional groups on SiO2. ∙OH, 1O2 and ∙O2– are confirmed to contribute to the degradation of TC. In addition, a catalytic mechanism is proposed in the Cu/Cu2O/SiO2/H2O2 system.