Bao Shidong, Liu Tao, Fu Heyun, Xu Zhaoyi, Qu Xiaolei, Zheng Shourong, Zhu Dongqiang
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
ACS Appl Mater Interfaces. 2023 Oct 4;15(39):45949-45959. doi: 10.1021/acsami.3c12413. Epub 2023 Sep 25.
CO hydrogenation via the reverse water gas shift (RWGS) reaction is a promising strategy for CO utilization while constructing Ni-based catalysts with high catalytic activity and perfect CO selectivity remains a great challenging. Here, we demonstrate that the product selectivity for CO hydrogenation can be significantly tuned from CH to CO by phosphating of SiO-supported Ni catalysts due to the geometric effect. Interestingly, nickel phosphide catalysts with different crystalline phases (NiP and NiP) differ sharply in CO conversion, and NiP is remarkably more active. Furthermore, we developed a facile strategy to confine small NiP nanoparticles in mesoporous SiO channels (NiP@SBA-15). Enhanced activity is exhibited on NiP@SBA-15, ascribed to the highly effective confinement effect. The in situ diffuse reflectance infrared Fourier transform spectroscopy and density functional theory calculations unveil that catalytic CO hydrogenation follows a direct CO dissociation route with adsorbed CO as the key intermediate. Notably, strong multibonded CO (threefold and bridge-bonded CO) is feasibly formed on the Ni catalyst accounting for CH as the dominant product whereas only weak linearly bonded CO exists on nickel phosphide catalysts resulting in almost 100% CO selectivity. The present results indicate that NiP@SBA-15 combining the geometric effect and the confinement effect can achieve near-unity CO selectivity and enhanced activity for CO hydrogenation.
通过逆水煤气变换（RWGS）反应进行CO加氢是一种很有前景的CO利用策略，然而构建具有高催化活性和完美CO选择性的镍基催化剂仍然极具挑战性。在此，我们证明，由于几何效应，通过对SiO负载的Ni催化剂进行磷化处理，CO加氢的产物选择性可以从CH显著调至CO。有趣的是，具有不同晶相（NiP和NiP）的磷化镍催化剂在CO转化率上有很大差异，且NiP的活性明显更高。此外，我们开发了一种简便的策略，将小尺寸的NiP纳米颗粒限制在介孔SiO通道中（NiP@SBA-15）。NiP@SBA-15表现出增强的活性，这归因于高效的限域效应。原位漫反射红外傅里叶变换光谱和密度泛函理论计算表明，催化CO加氢遵循以吸附的CO为关键中间体的直接CO解离途径。值得注意的是，在Ni催化剂上可形成强多键合的CO（三重键合和桥式键合的CO），这导致CH成为主要产物，而在磷化镍催化剂上仅存在弱线性键合的CO，从而实现了几乎100%的CO选择性。目前的结果表明，结合几何效应和限域效应的NiP@SBA-15可以实现接近100% 的CO选择性以及增强的CO加氢活性。
