Hydrogen production via the aqueous-phase reforming of methanol catalyzed by Ru(ii) complexes of PNNP ligands

Abstract

Hydrogen (H2) production by aqueous-phase reforming of liquid organic hydrogen carriers such as methanol, ethanol, and formic acid has attracted much recent interest as it offers a safe and convenient...

Recent progress in molecular transition metal catalysts for hydrogen production from methanol and formaldehyde

“…The final step involves formic acid dehydrogenation, resulting in the production of the third molecule of H 2 . 40…”

“…Subsequently, the formic acid dehydrogenates to produce a third molecule of H 2 along with CO 2 . 11 Various homogeneous 11,21–53 and heterogeneous 12–20 catalysts have been explored for hydrogen production from methanol and formaldehyde, where most of the heterogeneous catalytic systems work well at harsh reaction temperatures, while homogeneous molecular catalysts work well at lower operational temperatures. 21 Moreover, molecular catalysts also aid in a better understanding of the reaction mechanism, which further helps in designing efficient catalysts.…”

Panoramic Mechanistic Insights into Hydrogen Production via Aqueous-Phase Reforming of Methanol Catalyzed by Ruthenium Complexes of Bis-N-Heterocyclic Carbene Pincer Ligands

“…To this end, efforts have been devoted to H 2 production by catalytically dehydrogenating certain liquid organic hydrogen carrier (LOHC) molecules that are otherwise perfectly stable under ambient conditions. − Being inexpensive and readily available, methanol is one of the most attractive LOHCs; three molecules of H 2 can be generated by aqueous-phase reforming of methanol (APRM, eq ). ,,− normalC normalH 3 O H + H 2 normalO → 3 H 2 + normalC normalO 2 …”

“…With the best-performing complex C7 , mechanistic studies were carried out. In addition to the commonly used spectroscopic techniques/methods, including nuclear magnetic resonance (NMR) analysis of the reaction mixture, kinetic isotope effect (KIE) experiments, gas chromatographic analyses of the product mixture, and density functional theory (DFT) calculations of reaction free–energy profiles, our mechanistic studies rely heavily on the use of high-resolution electrospray ionization-mass spectrometry (HRESI-MS), a sensitive technique capable of providing valuable information on the identity of the many intermediates that are often hard to detect by any other means; ,,− its power and usefulness in helping deriving catalytically active species and putting forth plausible reaction mechanisms have recently been demonstrated in the recent works by us and other researchers. ,,,− …”

Production of carbon monoxide and hydrogen from methanol using a ruthenium pincer complex: a DFT study

“…Finding new and efficient routes is highly desirable. In this regard, transition metal-based homogeneous catalysts including Ru, 10 Ir, 11 Mn 12 and Fe 13 have been developed. In 2013, Beller and co-workers 10 b reported the first catalytic system for low-temperature aqueous methanol dehydrogenation using a PNP pincer ruthenium complex to release H 2 and CO 2 .…”