Graduate School of Science, Chiba University, Inage, Chiba 263-8522, Japan.
Phys Chem Chem Phys. 2022 Dec 7;24(47):28794-28803. doi: 10.1039/d2cp03713k.
Catalysts of methane decomposition to hydrogen and aromatization are inevitable for the development of natural gas applications. Metal catalysts have been developed to achieve highly efficient methane decomposition and aromatization under 1000 K using various substrates, such as zeolites and silica. Here, we performed a consecutive study on methane decomposition using Co-, Ni-, Cu-, Mo-, and Ru-based nanocatalysts in the bulk, on a SiO substrate, and in mesoporous SiO. The crystallite sizes of the bulk nanocatalysts, and nanocatalysts on nonporous and mesoporous SiO were controlled to 80-85, 30-70, and 3-11 nm, respectively. The nanocatalysts on mesoporous SiO exhibited high activity on hydrogen and benzene productions methane decomposition, owing to the nanosize effect of the nanocatalysts and adsorption potentials in the SiO mesopores. In particular, the Ni nanocatalysts on mesoporous SiO exhibited hydrogen production activity from 650 K, which was the lowest temperature, compared with those in previous reports on hydrogen production. In addition, the catalytic activity was maintained for over 15 h at 650 and 800 K with recyclability. The overoxidation of Ni species in the SiO mesopores might have promoted the transformation reaction of CH to CH and prevented coking by the largeness of the SiO mesopores in comparison with microporous media.
甲烷分解为氢气和芳构化的催化剂对于天然气应用的发展是必不可少的。已经开发了金属催化剂，以在 1000 K 以下使用各种基质（如沸石和二氧化硅）实现高效的甲烷分解和芳构化。在这里，我们在块状、SiO 基底和介孔 SiO 上使用 Co、Ni、Cu、Mo 和 Ru 基纳米催化剂连续研究了甲烷分解。块状纳米催化剂和非多孔及介孔 SiO 上的纳米催化剂的晶粒尺寸分别控制在 80-85、30-70 和 3-11 nm。由于纳米催化剂的纳米尺寸效应和 SiO 介孔中的吸附势，介孔 SiO 上的纳米催化剂在甲烷分解中表现出高的氢气和苯生产活性。特别是，与之前关于氢气生产的报道相比，Ni 纳米催化剂在介孔 SiO 上的氢气生产活性从 650 K 开始，这是最低的温度。此外，在 650 和 800 K 下，在可回收性方面，催化活性可以保持超过 15 小时。与微孔介质相比，SiO 介孔中 Ni 物种的过度氧化可能通过 SiO 介孔的大尺寸促进了 CH 向 CH 的转化反应，并防止结焦。
