Facilitating the Resumption of Hydroxyl Groups of Layered Triple Hydroxide Catalysts for Efficient Catalytic Ozone Decomposition

NiFe layered double hydroxide (LDH) catalysts exhibit promising potential for ozone decomposition due to their excellent activity and stability. Here, the layered triple hydroxide catalysts are synthesized by introducing low-cost metal ions to partially replace Ni²⁺ in NiFe-LDH to further enhance the catalytic activity and reduce the production cost of the catalysts. It has been shown that the Zn²⁺ substitution improves the activity of the Ni₃Fe₁-LDH catalysts for ozone decomposition, while the Mg²⁺ and Co²⁺ substitutions decrease it. Ni_1.5Zn_1.5Fe₁ layered triple hydroxide catalysts exhibit 90% ozone conversion within 168 h under weight hourly space velocity of 600 L·g^-1·h^-1 and 65% relative humidity. Experimental results show that the Zn²⁺ substitution not only increases the specific surface area but also decreases the interlayer water content, which helps the catalyst expose more hydroxyl group active sites. In addition, Zn²⁺ acting as a new functional site facilitates the resumption of hydroxyl groups, thus enhancing the catalytic activity for ozone decomposition. However, the Co²⁺ substitution destroys the structural properties of catalysts and suppresses the resumption of the active site, thus reducing the performance of the catalysts. This study demonstrates that the introduction of new functional sites is an effective strategy for the design and development of high-performance catalysts for ozone decomposition.