Selective formation of 2,5-dimethylfuran (DMF) by hydrogenolysis of lignocellulosic biomass-derived 5-hydroxymethylfurfural (HMF) is highly desirable for renewable liquid biofuel production. Here we have synthesized Cu–Pd bimetallic nanoparticles embedded in carbon matrix (Cu–Pd@C) by simple pyrolysis of Pd-impregnated Cu-based metal–organic frameworks (MOFs) followed by conventional hydrogenation route. It was found that Cu–Pd@C-B (solid–gas-phase hydrogenation route) with Cu–Pd bimetallic alloying exhibited brilliant catalytic performance at 120 °C under 15 bar H2 pressure to produce liquid DMF biofuel with 96.5% yield from HMF as compared with the Cu–Pd@C-A catalyst (liquid phase hydrogenation route), which gave 46.4% yield under the same conditions. X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge structure (XANES) studies reveal that Pd in Cu–Pd@C-B catalyst is electronically promoted by Cu with the unique intrinsic synergy of increased Pd–Pd bond distance and decreased Cu–Cu bond length, which eventually modulate the local atomic structural environment and result in enhanced catalytic activity. Moreover, the entrapped bimetallic nanoparticles with carbon shells in Cu–Pd@C-B catalyst further protect the active catalytic site from migration, aggregation, and leaching during hydrogenolysis reaction and improve the stability of the catalyst.

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.

Decisions are increasingly taken by both humans and machine learning models. However, machine learning models are currently trained for full automation—they are not aware that some of the decisions may still be taken by humans. In this paper, we take a first step towards the development of machine learning models that are optimized to operate under different automation levels. More specifically, we first introduce the problem of ridge regression under human assistance and show that it is NP-hard. Then, we derive an alternative representation of the corresponding objective function as a difference of nondecreasing submodular functions. Building on this representation, we further show that the objective is nondecreasing and satisfies α-submodularity, a recently introduced notion of approximate submodularity. These properties allow a simple and efficient greedy algorithm to enjoy approximation guarantees at solving the problem. Experiments on synthetic and real-world data from two important applications—medical diagnosis and content moderation—demonstrate that the greedy algorithm beats several competitive baselines.

Tetrahydrofurfuryl alcohol (THFAL) is a green solvent as well as significant platform chemical which can be obtained from biomass derived furfural. In this study new palladium exchanged vanadium incorporated supported...

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Metalated nanoporous organic polymers (M-POPs) combine covalent bonds and open metal sites to enable structural stability and single-site catalysis. In this work, we constructed two single-site Pd-metalated knitting aromatic polymers (Pd@KAP-1 and Pd@KAP-2) and explored their catalytic activity in lignocellulosic biomass-derived furfural (FFR) upgrading to tetrahydrofurfuryl alcohol (THFAL), a green industrial solvent. Pd@KAP-1 exhibits superior catalytic performance compared to Pd@KAP-2 toward FFR conversion, resulting in 80% conversion with a 95% selectivity toward THFAL. Using in situ DRIFTS analysis, we find that FFR strongly adsorbs on Pd@KAP-1, which is a key determining factor in its higher catalytic efficiency. Our X-ray photoelectron spectroscopic (XPS) measurements show a lower (∼0.3 eV) binding energy displacement of Pd-3d5/2 in Pd@KAP-1 compared to Pd@KAP-2. We attribute this to the presence of a biphenyl ring that enables partial charge transfer between the P and the Pd atoms inside the nanocavity of Pd@KAP-1 to facilitate catalytic hydrogenation. We also carried out a kinetic analysis showing that Pd@KAP-1 has a lower activation barrier than Pd@KAP-2 for the FFR hydrogenation process. Our study demonstrates a novel concept for designing efficient, robust, and sustainable metalated porous organic polymer-based heterogeneous nanocatalysts in biomass refinery industries.