Synthesis of bifunctional Ru–Pd catalysts following a double reduction method: hydrogenation/dehydrogenation of liquid organic hydrogen carriers. Issue 15 (29th June 2022)

• Record Type: Journal Article
• Authors: Zhu, Ting; Wang, Ran; Chen, Ziteng; Ji, Feng; Dong, Yuan; Yang, Ming
• Is Part Of: Catalysis science & technology. Volume 12:Issue 15(2022)
• Page Start: 4763
• Page End: 4775
• Publication Date: 2022-06-29
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/d2cy00425a
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : Treatment of Ru2.5 Pd2.5 /H2 catalyst with Ar–H2 mixture exposed strong acid sites, prompting further reduction of Ru n + and Pd 2+, leading to enhanced interaction of Ru and Pd with carrier, possessing excellent hydrogenation–dehydrogenation activity. Abstract : The problem of safe and efficient storage and transportation of hydrogen energy limits the large-scale development of the "hydrogen economy". The liquid organic hydrogen storage technology is based on reversible catalytic hydrogenation and dehydrogenation reactions of unsaturated compounds to achieve safe and efficient storage and release of hydrogen. Heterogeneous catalysts with excellent catalytic capacity and stability should be developed to drive the reactions. However, it is a challenge to develop these catalysts. We fabricated a series of RuPd-based and supported catalysts following two different methods, and the catalytic hydrogenation and dehydrogenation activities of these catalysts were systematically investigated. The experiment results implied that the Pd2.5 Ru2.5 /H2 (double reduction method) catalyst exhibited catalytic hydrogenation rates that were similar to those of Pd2.5 Ru2.5 /L (when reduced by NaBH4 ). The former exhibited much better catalytic dehydrogenation rates than the latter. The Pd2.5 Ru2.5 /H2 catalyst also exhibited much better catalytic recyclability than the Pd2.5 Ru2.5 /L catalyst, and the conclusion was arrived at by conducting 10 cycles of hydrogenation–dehydrogenation tests. The relationship between the catalytic performances and the catalyst's properties was further investigated using a combination of H2 -TPR, NH3 -TPD, XPS, and TEM techniques. The characterization results revealed that the double reduction process could be used to enhance the extent of electronic interaction of the RuPd active sites with the support, and more numbers of strong acidic sites and active sites could be generated. Furthermore, DFT calculations also revealed that 8H-NPCZ and 4H-NPCZ formed stable adsorption structures on the Ru3 Pd3 /Al2 O3 (100) surface, facilitating catalytic reactions. Notably, the reaction energies of Ru3 Pd3 /Al2 O3 (100) were 1.16 eV, 1.42 eV, and 1.63 eV, indicating that the dehydrogenation process (8H-NPCZ → 4H-NPCZ and 4H-NPCZ → NPCZ) occurred easily. All the above-mentioned characteristics make the Pd2.5 Ru2.5 /H2 catalyst an excellent catalyst for hydrogenation and dehydrogenation and endow it with outstanding catalytic capacity and recyclability.