Al-Ali Latifa Ibrahim, Elmutasim Omer, Al Ali Khalid, Singh Nirpendra, Polychronopoulou Kyriaki
Mechanical Engineering Department, Khalifa University, Abu Dhabi 127788, United Arab Emirates.
Center for Catalysis and Separations, Khalifa University, Abu Dhabi 127788, United Arab Emirates.
Nanomaterials (Basel). 2022 Apr 22;12(9):1435. doi: 10.3390/nano12091435.
Hydrodeoxygenation (HDO) reaction is a route with much to offer in the conversion and upgrading of bio-oils into fuels; the latter can potentially replace fossil fuels. The catalyst's design and the feedstock play a critical role in the process metrics (activity, selectivity). Among the different classes of catalysts for the HDO reaction, the transition metal phosphides (TMP), e.g., binary (Ni2P, CoP, WP, MoP) and ternary Fe-Co-P, Fe-Ru-P, are chosen to be discussed in the present review article due to their chameleon type of structural and electronic features giving them superiority compared to the pure metals, apart from their cost advantage. Their active catalytic sites for the HDO reaction are discussed, while particular aspects of their structural, morphological, electronic, and bonding features are presented along with the corresponding characterization technique/tool. The HDO reaction is critically discussed for representative compounds on the TMP surfaces; model compounds from the lignin-derivatives, cellulose derivatives, and fatty acids, such as phenols and furans, are presented, and their reaction mechanisms are explained in terms of TMPs structure, stoichiometry, and reaction conditions. The deactivation of the TMP's catalysts under HDO conditions is discussed. Insights of the HDO reaction from computational aspects over the TMPs are also presented. Future challenges and directions are proposed to understand the TMP-probe molecule interaction under HDO process conditions and advance the process to a mature level.
加氢脱氧（HDO）反应是生物油转化和升级为燃料的一条极具潜力的途径；后者有可能替代化石燃料。催化剂的设计和原料在工艺指标（活性、选择性）中起着关键作用。在用于HDO反应的不同类型催化剂中，过渡金属磷化物（TMP），例如二元（Ni2P、CoP、WP、MoP）和三元Fe-Co-P、Fe-Ru-P，由于其具有变色龙般的结构和电子特性，使其与纯金属相比具有优势，且成本较低，因此在本综述文章中被选为讨论对象。文中讨论了它们用于HDO反应的活性催化位点，同时介绍了其结构、形态、电子和键合特征的具体方面以及相应的表征技术/工具。文中对TMP表面上代表性化合物的HDO反应进行了深入讨论；列举了木质素衍生物、纤维素衍生物和脂肪酸中的模型化合物，如酚类和呋喃类，并根据TMP的结构、化学计量和反应条件解释了它们的反应机理。讨论了HDO条件下TMP催化剂的失活情况。还介绍了从计算角度对TMP上HDO反应的见解。提出了未来的挑战和方向，以了解HDO工艺条件下TMP与探针分子的相互作用，并将该工艺推进到成熟水平。
