Rodriguez-Gomez Alberto, Pereñiguez Rosa, Caballero Alfonso
Instituto de Ciencia de Materiales de Sevilla (CSIC-University of Seville) and Departamento de Quimica Inorganica, University of Seville , Avda. Américo Vespucio, 49, 41092, Seville, Spain.
J Phys Chem B. 2018 Jan 18;122(2):500-510. doi: 10.1021/acs.jpcb.7b03835. Epub 2017 Aug 11.
A series of four Ni catalysts supported on SBA-15 and on a high SiO surface area have been prepared by modified impregnation (ImU) and deposition-precipitation (DP) methods. The catalysts have been extensively characterized, including in situ XAS (bulk sensitive) and XPS (surface sensitive) techniques, and their catalytic activities evaluated in the dry reforming reaction of methane (DRM). The combined use of XPS and XAS has allowed us to determine the location of nickel particles on each catalyst after reduction at high temperature (750 °C). Both Ni/SiO-DP and Ni/SBA-15-DP catalysts yield well-dispersed and homogeneous metallic phases mainly located in the mesoporosity of both supports. On the contrary, the Ni/SiO-ImU and Ni/SBA-15-ImU catalysts present a bimodal distribution of the reduced nickel phase, with nickel metallic particles located out and into the mesoporous structure of SiO or the SBA-15 channels. The Ni/SBA-15-DP catalyst was found the most stable and performing system, with a very low level of carbon deposition, about an order of magnitude lower than the equivalent ImU catalyst. This outstanding performance comes from the confinement of small and homogeneous nickel particles in the mesoporous channels of SBA-15, which, in strong interaction with the support, are resistant to sintering and coke deposition during the demanding reaction conditions of DRM.
通过改进的浸渍法（ImU）和沉积沉淀法（DP）制备了一系列负载在SBA - 15和高SiO表面积载体上的四种镍催化剂。对这些催化剂进行了广泛的表征，包括原位X射线吸收光谱（体相灵敏）和X射线光电子能谱（表面灵敏）技术，并在甲烷干重整反应（DRM）中评估了它们的催化活性。XPS和XAS的联合使用使我们能够确定高温（750℃）还原后每种催化剂上镍颗粒的位置。Ni/SiO - DP和Ni/SBA - 15 - DP催化剂都产生了主要位于两种载体介孔中的分散良好且均匀的金属相。相反，Ni/SiO - ImU和Ni/SBA - 15 - ImU催化剂呈现出还原镍相的双峰分布，镍金属颗粒位于SiO或SBA - 15通道的介孔结构内外。发现Ni/SBA - 15 - DP催化剂是最稳定且性能最佳的体系，碳沉积水平非常低，比等效的ImU催化剂低约一个数量级。这种出色的性能源于SBA - 15介孔通道中均匀的小镍颗粒的限制，这些颗粒与载体有强烈的相互作用，在DRM苛刻的反应条件下能抵抗烧结和积碳。
