Confined Ni-In intermetallic alloy nanocatalyst with excellent coking resistance for methane dry reforming
Confined Ni-In intermetallic alloy nanocatalyst with excellent coking resistance for methane dry reforming
复制标题
DOI：
10.1016/j.jechem.2021.05.017
复制
发表时间：
2021-06-07
影响因子：
13.1
通讯作者：
Peng, Honggen
中科院分区：
文献类型：
--
作者：
Liu, Wenming;Li, Le;Peng, Honggen
二氧化碳和甲烷是导致严重全球变暖的两种主要温室气体。幸运的是，甲烷干法重整(DRM)是几十年前发展起来的一种非常重要的反应，可以将这两种主要温室气体转化为增值的合成气或氢气。阻碍其工业化的主要问题是镍基催化剂结焦严重。本论文制备了一系列受限铟镍(In-Ni)金属间化合物纳米催化剂(InxNi@SiO_2)，并对DRM反应表现出了良好的抗结焦性能。当In负载量为0.5wt.%(In 0.5Ni@SiO_2)时，即使经过430h的长期稳定性测试，其抗积碳能力和DRM活性仍达到最佳平衡。提高的碳阻可以归因于In-Ni金属间化合物合金中核壳结构的限制和In-Ni金属间化合物中较小的电负性使电子从In向Ni的转移。金属Ni表面SiO_2壳层和电子云密度的增加都会削弱Ni活化C-H键的能力，减少甲烷的深度裂解过程。原位漫反射红外傅里叶变换光谱(原位漂移)表明，在受限InNi金属间化合物纳米晶上的反应符合朗缪尔-辛舍伍德(L-H)机理。该工作对设计高效利用这两种主要温室气体的甲烷干法重整催化剂具有一定的指导意义。(C)2021科学出版社和中国科学院大连化学物理研究所。由Elsevier B.V.和科学出版社出版。版权所有。
Carbon dioxide and methane are two main greenhouse gases which are contributed to serious global warming. Fortunately, dry reforming of methane (DRM), a very important reaction developed decades ago, can convert these two major greenhouse gases into value-added syngas or hydrogen. The main prob-lem retarding its industrialization is the seriously coking formation upon the nickel-based catalysts. Herein, a series of confined indium-nickel (In-Ni) intermetallic alloy nanocatalysts (InxNi@SiO2) have been prepared and displayed superior coking resistance for DRM reaction. The sample containing 0.5 wt.% of In loading (In0.5Ni@SiO2) shows the best balance of carbon deposition resistance and DRM reac-tivity even after 430 h long term stability test. The boosted carbon resistance can be ascribed to the con-finement of core-shell structure and to the transfer of electrons from Indium to Nickel in In-Ni intermetallic alloys due to the smaller electronegativity of In. Both the silica shell and the increase of electron cloud density on metallic Ni can weaken the ability of Ni to activate C-H bond and decrease the deep cracking process of methane. The reaction over the confined InNi intermetallic alloy nanocata-lyst was conformed to the Langmuir-Hinshelwood (L-H) mechanism revealed by in situ diffuse reflec-tance infrared Fourier transform spectroscopy (in-situ DRIFTS). This work provides a guidance to design high performance coking resistance catalysts for methane dry reforming to efficiently utilize these two main greenhouse gases. (c) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.