A N-rich porous organic polymer-anchored bimetallic Cu–Pd nanoalloy exhibited superior catalytic activity with improved stability for biomass-derived selective hydrodeoxygenation of vanillin.

Enormous efforts have been initiated in the production of biobased fuels and value-added chemicals via biorefinery owing to the scarcity of fossil resources and huge environmental synchronization. Herein, non-noble metal-based metal/mixed metal oxide supported on carbon employing a metal–organic framework as a sacrificial template is demonstrated for the first time in the selective hydrodeoxygenation (HDO) of biomass-derived furfural (FFR) to 2-methyl furan (MF). The aforementioned catalyst (referred to as Cu/CuFe2O4@C-A) exhibited extraordinary catalytic proficiency (100% selectivity toward MF) compared with the conventional Cu/CuFe2O4@C-B catalyst which was prepared by the wet impregnation method. High-resolution transmission electron microscopy and synchrotron X-ray diffraction studies evidenced the existence of both metal (Cu) and mixed metal oxide (CuFe2O4) phases, in which the metal could help in hydrogenation to alcohol and metal oxide could assist in the hydroxyl group removal step during HDO reaction. The stabilization of encapsulated metal/metal oxide nanoparticles in the carbon matrix, modulation of the electronic structure, and regulation of geometric effects in the Cu/CuFe2O4@C-A are thought to play an important role in its excellent catalytic performance, confirmed by X-ray photoelectron spectroscopy and X-ray absorption spectroscopy investigations. Furthermore, the structure and activity interconnection was confirmed by in situ attenuated total reflection–IR studies, which manifested the strong interfacial interaction between FFR and the Cu/CuFe2O4@C-A catalyst. This finding was further supported by NH3 temperature-programmed desorption analysis, which suggested that the presence of more Lewis/weak acidic sites in this catalyst was beneficial for the hydrogenolysis step in HDO reaction. Additionally, H2 temperature-programmed reduction studies revealed that the adsorption of H2 was stronger on the Cu/CuFe2O4@C-A than that over the conventional Cu/CuFe2O4@C-B catalyst; thus, the former catalyst promoted activation of H2. A detailed kinetic analysis which demonstrated the lower activation energy barrier along with dual active sites attributed for the activation of the two separate reactions in the HDO process on the Cu/CuFe2O4@C-A catalyst. This work has great implication in developing a highly stable catalyst for the selective upgradation of biomass without deactivation of metal sites in extended catalytic cycles and opens the door of opportunity for developing a sustainably viable catalyst in biomass refinery industries.

In recent times, selective hydrogenation of biomass-derived 5-hydroxymethylfurfural(5-HMF) to produce novel difuranic polyol scaffold 2,5-dihydroxymethylfuran (DHMF) has attracted the interests of the many researchers due to its peculiar symmetrical structure as well as its wide application as a monomer for the preparation of cross-linked polyesters and polyurethane. Copper-based catalysts have been explored accountable for the selective catalytic hydrogenation however the hurdles are still associated with the strongly reducing H2 atmosphere and oxidizing C-O bond that makes the Cu 0 and Cu x+ surface active species unstable, limiting the rational design of highly efficient integrated catalyst systems. To address this, herein, we built catalytic systems for 5-HMF hydrogenation with stable and balanced Cu 0 and Cu x+ active surface species inside the nanocage of catechol based Porous-Organic-Polymer (POP) endowed with large surface areas, impressive stabilities, and spatial restriction inhibiting NPs aggregation.Batch reactor screening indentified that superior catalytic performance (DHMF selectivity of 98%) has been achieved with our newly designed Cu@C-POP at 150ºC temperature and 20 bar H2 pressure, which was also higher than that of other reported copper catalysts. Comprehensive characterizations understanding with H2-TPR and XPS study revealed that substantially boosted activity is induced by the presence of bulk CuOx phase and atomically dispersed Cu species incorporating isolated Cu ions, which are further confirmed through the positive binding energy shift of Cu-2p3/2 XPS spectra (~0.4eV). The Cu environment in our catalytic systems comprises predominantly square planar (well probably Jahn-Teller distorted Oh) which we gleaned from the EXAFS analysis featuring two adjacent copper atoms with the valence state in between of 0 and +2 as validated by XANES absorption edge positions. EXAFS studies further revealed a

Hydrodeoxygenation (HDO) is a promising route for the upgrading of bio-oils to eco-friendly biofuel produced from lignocellulose. Herein, we report the sequential synthesis of a hybrid nanocatalyst Co x P@POP, where substoichiometric Co x P nanoparticles are distributed in a porous organic polymer (POP) via solid-state phosphidation of the Co 3 O 4 @POP nanohybrid system. We also explored the catalytic activity of the above two nanohybrids toward the HDO of vanillin, a typical compound of lignin-derived bio-oil to 2-methoxy-4-methylphenol, which is a promising future biofuel. The Co x P@POP exhibited superior catalytic activity and selectivity toward desired product with improved stability compared to the Co 3 O 4 @POP. Based on advanced sample characterization results, the extraordinary selectivity of Co x P@POP is attributed to the strong interaction of the cation of the Co x P nanoparticle with the POP matrix and the consequent modifications of the electronic states. Through attenuated total reflectance-infrared spectroscopy, we have also observed different interaction strengths between vanillin and the two catalysts. The decreased catalytic activity of Co 3 O 4 @POP compared to Co x P@POP catalyst could be attributed to the stronger adsorption of vanillin over the Co 3 O 4 @POP catalyst. Also from kinetic investigation, it is clearly demonstrated that the Co 3 O 4 @POP has higher activation energy barrier than the Co x P@POP, which also reflects to the reduction of the overall efficiency of the Co 3 O 4 @POP catalyst. To the best of our knowledge, this is the first approach in POP-encapsulated cobalt phosphide catalyst synthesis and comprehensive study in establishing the structure− activity relationship in significant step-forwarding in promoting biomass refining.

Robust nanoarchitectures based on surfactant‐free ultrafine Pd nanoparticles (NPs) (2.7–8.2±0.5 nm) have been developed by using the incipient wetness impregnation method with subsequent reduction of PdII species encaged in the 1,3,5‐triazine‐functionalized nitrogen‐rich porous organic polymer (POP) by employing NaBH4, HCHO, and H2 reduction routes. The Pd‐POP materials prepared by the three different synthetic methods consist of virtually identical chemical compositions but have different physical and texture properties. Strong metal–support interactions, the nanoconfinement effect of POP, and the homogeneous distribution of Pd NPs have been investigated by performing 13C cross‐polarization (CP) solid‐state magic angle spinning (MAS) NMR, FTIR, and X‐ray photoelectron spectroscopy (XPS), along with wide‐angle powder XRD, N2 physisorption, high‐resolution (HR)‐TEM, high angle annular dark field scanning transmission electron microscopy (HAADF‐STEM), and energy‐dispersive X‐ray (EDX) mapping spectroscopic studies. The resulting Pd‐POP based materials exhibit highly efficient catalytic performance with superior stability in promoting biomass refining (hydrodeoxygenation of vanillin, a typical compound of lignin‐derived bio‐oil). Outstanding catalytic performance (≈98 % conversion of vanillin with exclusive selectivity for hydrogenolysis product 2‐methoxy‐4‐methylphenol) has been achieved over the newly designed Pd‐POP catalyst under the optimized reaction conditions (140 °C, 10 bar H2 pressure), affording a turnover frequency (TOF) value of 8.51 h−1 and no significant drop in catalytic activity with desired product selectivity has been noticed for ten successive catalytic cycles, demonstrating the excellent stability and reproducibility of this catalyst system. A size‐ and location‐dependent catalytic performance for the Pd NPs with small size (1.31±0.36 and 2.71±0.25 nm) has been investigated in vanillin hydrodeoxygenation reaction with our newly designed Pd‐POP catalysts. The presence of well‐dispersed electron‐rich metallic Pd sites and highly rigid cross‐linked amine‐functionalized POP framework with high surface area is thought to be responsible for the high catalytic activity and improvement in catalyst stability.

A novel Pd-based catalyst hosted over a nitrogen enriched fibrous porous-organic-polymer with a high density of step sites and exhibits versatile catalytic performance over different types of vegetable oils to furnish long chain diesel-range alkanes.

Porous-Organic-Polymers (POPs) constructed through covalent bonds have raised tremendous research interest because of their suitability to develop robust catalysts and their successful production with improved efficiency. In this work, we have designed and explored the properties and catalytic activity of template-free construction hydroxy (-OH) group enriched porous-organic-polymer (Ph-POP) bearing functional Pd nanoparticles (Pd-NPs) by one-pot condensation of phloroglucinol (1,3,5-trihydroxybenzene) and terephthalaldehyde followed by solid phase reduction with H 2 . The encapsulated Pd-NPs rested within welldefined POP nanocages and remained undisturbed from aggregation and leaching. This polymer hybrid nanocage Pd@Ph-POP is found to enable efficient liquid-phase hydrodeoxygenation (HDO) of acetophenone (AP) with high selectivity (99%) of ethylbenzene (EB) and better activity than its Pd@Al 2 O 3 counter-part. Our investigation demonstrates a facile, scalable, catalyst-template free methodology for developing novel porous-organic-polymer catalysts and next generation efficient greener chemical processes from platform molecules to value-added chemicals. With the aid of comprehensive in situ ATR-IR spectroscopic experiments, it is suggested that EB can be more easily desorbed in solution, reflecting from the much weaker but resolved signals at 1494 cm -1

The rational design of effective and inexpensive electrocatalysts for solar-powered water splitting is under intense focus to overcome barriers during half-cell reactions. Towards addressing this issue, we designed and sequentially synthesized Fe 2 O 3 and FeP nanoparticles encapsulated on a carbonaceous matrix nanoarchitecture (Fe 2 O 3 @C and FeP@C) from an Fe-based 1,4benzenedicarboxylate framework (Fe-MIL-88B) through hightemperature pyrolysis followed by a solid-/gas-phase lowtemperature phosphidation process. These nanoparticles were employed as bifunctional electrocatalysts deposited onto a Si photoelectrode assembly. The changes in morphological and electronic properties of the as-prepared catalysts were investigated after controlled heat treatment. As-synthesized Fe 2 O 3 @C/Si and FeP@C/Si were found to be superior bifunctional photoelectrodes in a neutral aqueous medium under simulated solar irradiation of 100 mW cm À2 . Fe 2 O 3 @C/Si exhibited high activity for the oxygen evolution reaction (OER), providing a photoanodic current density of 2.5 mA cm À2 at 1.65 V (vs. RHE), which was driven by the type-II heterojunction model in the Fe 2 O 3 @C/Si system. In parallel, the FeP@C/Si materials exhibited noticeable hydrogen evolution reaction (HER) activity, generating 10 mA cm À2 cathodic current at À0.07 V (vs. RHE). The varied performance could be attributed to the bulk size dependency of the crystalline Fe 2 O 3 phase on the conductive sp 2 -hybridized carbon framework and an intrinsic synergetic effect in the FeP@C, which originates from electronic interactions between Fe and P with high porosity, and which permits easy diffusion of the electrolyte and efficient electron transfer during hydrogen generation.[a] S.