Exploring High-Activity Copper Doping Zirconia Bi-Metal Oxides Catalysts for Methane Conversion at Room Temperature

Abstract

Recently, a large quantity of research has been done on the conversion of CH4.(1) Compared to photo-catalysis and thermo-catalysis with precious metal catalysts and high reaction temperatures, the electro-catalysis path, which are always performed at room temperature, demonstrates more potential. In this regard, the electrochemical oxidation and conversion of CH4 to commodity chemicals, such as wide-application liquid alcohols, shows obvious economic benefit and high energy/ conversion-efficient. Zirconia (ZrO2) has rich Lewis acid active sites and huge electron acceptability, showing a remarkable adsorption capacity of CO32-.(2) Based on the above characters, zirconia-based hybrid has attracted a lot of attention and made some breakthroughs. In particular, transition metal oxide (TMO, such as NiO and Co3O4) doping ZrO2 forming TMO/ZrO2 compound demonstrates the potential of methane oxidation with CO32- at room temperature. Compared to NiO and Co3O4, copper-based (Cu) catalysts have a high activity and a long-term durability on forming liquid and gas organics of C1 catalysis reaction system (CO2 reduction reaction) at room temperature.(3-5) Hence, we present a facile strategy of using Cu ions doping ZrO2 to activate the hybrid activity by manipulating its crystal and electronic structure. As expected, the unique cylindrical ZrO2:CuOx catalyst shows remarkable CH4 oxidation performance with large current density differences (13.35 mA cm-2) and long-term electrochemical stability (negligible attenuation (10 %) after 48 hours). According to theoretical and experimental observations of the CH4 oxidation on ZrO2: CuOx hybrid, the high activity and durability of the hybrid should be attributed to 1) strong synergistic-coupling effect; 2) the unique doping structure forming favorable electronic and crystal structure; 3) fast oxidation reaction mechanism by shortening the reaction path. The mechanism could be described as that ZrO2 facilitating CO32- adsorption, then CO32- as the oxidizing agent source rapidly oxidizes CH4 adsorbed on the surface of Cu in zirconia. Keywords: ZrO2:CuOx, Methane conversion, high activity, Unique doping structure Uncategorized References 1. B. Wang, S. Albarracín-Suazo, Y. Pagán-Torres and E. Nikolla, Catal. Today, 285, 147 (2017). 2. M. Ma, B. J. Jin, P. Li, M. S. Jung, J. I. Kim, Y. Cho, S. Kim, J. H. Moon and J. H. Park, Advanced science, 4, 1700379 (2017). 3. H. Oguchi, H. Kanai, K. Utani, Y. Matsumura and S. Imamura, Applied Catalysis A: General, 293, 64 (2005). 4. Z. Riguang, L. Hongyan, L. Lixia, L. Zhong and W. Baojun, Applied Surface Science, 257, 4232 (2011). 5. S. Tada, K. Larmier, R. Büchel and C. Copéret, Catalysis Science & Technology, 8, 2056 (2018).