Current synthesis techniques for metal oxide (MO_x)-supported catalysts have certain limitations of undesired target loading, ineffective dispersion of active species over the surface, uncontrolled particle size of active species, and complicated synthesis steps. We developed a one-pot chemical vapor deposition (OP-CVD) methodology; by using which a solid metal precursor forms a vapor in a controlled condition and gets supported over the surrounding matrix. The theoretical stability followed by experimental validation using TGA is crucial for selecting the metal precursors. Three simple steps viz. premixing, dispersion, and rapid fixation by calcination are involved in the catalyst development via the OP-CVD approach. This study solely focused on the synthesis of 3d transition MO_x over ceria support. The physicochemical characterizations of the prepared catalysts were performed by XRD, ICP-OES, SEM-EDX, CO pulse chemisorption, XANES, and EXAFS analyses to understand the crystal structure of involved species, target metal loading, dispersion, and particle size and prove the feasibility and viability of OP-CVD. The prepared catalysts were further tested for reverse water gas shift (RWGS) reaction to link their structural information with activity. The RWGS reaction data showed that the CO activity and CO selectivity were metal - and metal precursor-dependent. Higher CO activity of > 0.1 mol/h g-cat was observed for Cu and Co-based catalysts, with CO selectivity of ∼100 %. This study provides an opportunity to produce efficient supported catalysts in a convenient way, providing effective catalytic activity.

中文翻译：

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通过一锅法化学气相沉积 （OP-CVD） 技术开发铈负载金属氧化物 （MOx/CeO2） 催化剂：结构和反向水气变换反应研究


目前金属氧化物 （MO_x） 负载催化剂的合成技术存在一定的局限性，例如不需要的靶负载、活性物质在表面的无效分散、活性物质的粒径不受控制以及合成步骤复杂。我们开发了一种一锅法化学气相沉积 （OP-CVD） 方法;通过使用它在受控条件下形成蒸汽并在周围的基体上得到支撑。使用 TGA 进行实验验证的理论稳定性对于选择金属前驱体至关重要。通过 OP-CVD 方法进行催化剂开发涉及三个简单的步骤，即预混合、分散和通过煅烧快速固定。本研究仅侧重于 3d 过渡 MO_x 在铈支撑上的合成。通过 XRD、ICP-OES、SEM-EDX、CO 脉冲化学吸附、XANES 和 EXAFS 分析对所制备的催化剂进行物理化学表征，以了解所涉物种的晶体结构、目标金属负载、分散和粒径，并证明 OP-CVD 的可行性和可行性。进一步测试了制备的催化剂进行反向水气转移 （RWGS） 反应，以将其结构信息与活性联系起来。RWGS 反应数据表明，CO 活性和 CO 选择性取决于金属和金属前驱体。观察到 Cu 和 Co 基催化剂的 > 0.1 mol/h g-cat 的 CO 活性较高，CO 选择性为 ∼ 100 %。本研究为以方便的方式生产高效的负载型催化剂提供了机会，从而提供有效的催化活性。