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We developed a series of heteropolyacid-modified lignin-MOF derived bimetallic catalyst for the efficient in situ hydrogenation/hydrodeoxygenation of biomass-derived 5-hydroxymethylfurfural using isopropanol as hydrogen-donating solvent. [Display omitted] Catalytic conversion of biomass-derived value-added chemicals was of great significance for the utilization of renewable biomass resources to instead of fossil chemicals. Biomass-derived lignin was regarded as an important support and 5-hydroxymethylfurfural (HMF) was a vital platform chemical derived from cellulose. Herein, a series of lignin-MOF hybrid catalysts were prepared and modified with different heteropolyacids (HPAs), which were then successfully introduced into the selective conversion of HMF to 5-hydroxymethylfurfuryl alcohol (MFA). The effect of different HPA, calcination temperature, etc. were all studied, and all catalysts were well characterized. It was confirmed that silicotungstic acid modified catalyst (Ni 3 Co-MOF-LS@HSiW) exhibited the best catalytic performance, while the highest conversion of HMF was up to 100%, with the best MFA yield of 86.5%. The finding in this study could provide novel insights for the utilization of lignin and preparation of value-added biomass-derived chemicals. [ABSTRACT FROM AUTHOR]

Lignin is an attractive renewable source of aromatics with a low effective hydrogen to carbon ratio (H/Ceff). The catalytic hydrodeoxygenation (HDO) of lignin-derived model compounds is a key strategy for lignin upgrading. In this work, the HDO of guaiacol, a typical lignin-derived compound, was carried out over metal–organic framework (MOF)-derived Ni-based catalysts. A monometallic Ni-MOF catalyst and different ratios of bimetallic NiMo-MOF catalysts were synthesized by a hydrothermal process, followed by a carbonization process. Among these catalysts, Ni3Mo1@C exhibited an excellent catalytic performance, affording a guaiacol conversion of 98.8% and a cyclohexanol selectivity of 66.8% at 240 °C and 2 MPa H2 for 4 h. The addition of Mo decreased the particle size of the spherical structure and improved the dispersion of metal particles. The synergistic effect between Ni and Mo was confirmed by various means, including ICP, XRD, SEM, TEM, and NH3-TPD analyses. In addition, the effect of the reaction temperature, time, and H2 pressure during the HDO process is discussed in detail. [ABSTRACT FROM AUTHOR]

Designing efficient and robust oxygen evolution reaction (OER) electrocatalysts is of great importance for various electrochemical energy storage and conversion applications. Herein, we developed IrP2 nanocrystals uniformly anchored in P,N-codoped carbon nanosheets (IrP2@PNC-NS) as highly active OER electrocatalysts. The ultrathin PNC-NS reconstructs an agaric-like porous structure, which can inhibit the agglomeration of the IrP2 nanocrystals effectively. Moreover, the in-situ phosphatization leads to the formation of a strong electron interaction between PNC-NS and IrP2 nanocrystals, endowing the heterostructure materials with satisfying synergistic effects. Benefiting from the collaborative advantages of ideal configuration structure and favorable synergistic effects, IrP2@PNC-NS exhibits excellent OER performance with a low overpotential of 221 mV at 10 mA cm−2, and a small Tafel slope of 37.5 mV dec−1. DFT calculations reveal that the synergistic effects derived from the IrP2/PNC interfaces, which can effectively tune the activation barriers towards facilitating the oxygen evolution process. This work provides new insight into the design of heterostructure materials for advanced OER electrocatalysts. [ABSTRACT FROM AUTHOR]

The industrial production of monophenols was mainly dependent on fossil resources, due to growing energy demand and escalating environmental issues, more efficient and sustainable strategy, such as utilization of biomass as raw materials to economically produce monophenols, was desired, which could liberate us from the reliance on fossil resource and was of great industrial and social significance. Herein, a novel strategy was reported to produce biomass-derived monophenols from lignin by directly deconstructing C-O bond under mild conditions. A series of NiM-MOFs (M=Co, Mo, and Cu) derived bimetallic catalysts were synthesized via a simple hydrothermal method, which were characterized by XRD, SEM, TEM, XPS and NH 3 -TPD. The synergistic effect between the Ni and Mo greatly improved the catalytic activity and inhibited the transformation to by-products. In addition, we explored a new binary solvents system of MeOH-THF to effectively enhance the selectivity of monophenols. Under optimal catalytic conditions, Ni4Mo1/C-BN catalyst could break the C-O bonds in lignin dimer under 160 ℃ to afford phenol and benzoic acid, and the possible reaction pathway was proposed. The high yield of lignin oil from the oxidation of various realistic lignin also confirmed the superiority of this catalytic system. The lignin depolymerization products were characterized by element analysis, GPC and GC-MS, confirming the presence of mainly guaiacyl-type (G) products, while the highest yield was assigned to vanillin. • Ni4Mo1/C-BN showed best activity for lignin dimer and lignin oxidation. • The introduction of Mo can greatly increase the lignin oil from 62 wt% to 93 wt%. • A new binary solvent was exploited for the oxidative depolymerization of lignin. [ABSTRACT FROM AUTHOR]

• Different organic ligands had great effects on the catalyst properties. • Phosphotungstic acid had positive impact on catalysts acidity. • Phosphotungstic acid modified Co-based catalyst showed best catalytic activity. Catalytic transfer hydrogenation (CTH) was recognized as a promising technique for converting various lignin derivatives to fuels and high-value compounds in heterogeneous systems. Herein, Co@C catalysts with diverse organic ligands, Keggin-type heteropolyacids, acid addition quantities, and metal/organic ligand molar ratios were synthesized via one-pot hydrothermal processes and carbonization methods. The optimized catalyst demonstrated highly efficient active hydrogen generation from isopropanol and the best conversion (100 %) for vanillin (VAN) hydrodeoxygenation (HDO) with 90 % 2-methoxy-4-methylphenol (MMP) yield at 180 °C for one hour under mild conditions of 0 MPa N 2 (hydrogen-free circumstance), which were strongly connected to the higher specific surface area (154.45 m2/g), acidic site density (4.67 mmol/g), and stronger metal-P interactions of the Co(H 4)@C-HPW 0.25 catalyst. The findings in this work provided an advanced thinking for designing high-performance non-noble-metal catalysts that could be applied in the catalytic HDO transformation of various biomass derivatives into green fuel and chemicals under mild circumstances. [ABSTRACT FROM AUTHOR]

5-Hydroxymethylfurfural (HMF) is a very important chemical intermediate, while it can be hydrogenated into various value-added chemicals. However, the hydrogenation of HMF over non-precious metal catalysts still remains as a challenging problem. In this study, lignosulfonate (LS) was used as carbon resource, and successfully introduced into MOFs structure. Then, a series of lignin-MOF derived catalysts (Ni n Co-MOF-LS) were prepared by the hydrothermal method with different ratios of Ni and Co metals. The selective conversion of hydroxymethylfurfural (HMF) to 5-methylfurfuryl alcohol (MFA) was achieved over Ni n Co-MOF-LS catalyst in a N 2 atmosphere with isopropanol as solvent. The Ni/Co metal ratios and calcination temperature played a key role in the catalytic performance of the catalyst. The catalysts showed good catalytic performance in the selective hydrogenation of HMF to MFA through an in-depth study of various reaction parameters such as temperature, pressure, reaction time and catalyst dosage. The coordination of lignosulfonate and MOFs provide a novel alternative for the utilization of lignin resource and the upgrading of biomass-derived chemicals. • Lignin was successfully introduced into MOF to for spherical NiCo-bimetallic catalyst. • Ni3Co-MOF-LS-0.5 showed good activity for the conversion of 5-hydroxymethylfurfural to 5-hydroxymethylfurfurfuryl alcohol. • The yield of 5-hydroxymethylfurfurfuryl alcohol was about 73% over Ni3Co-MOF-LS-0.5. [ABSTRACT FROM AUTHOR]

Guaiacol, a typical lignin-derived phenolic compound, can be converted to high value-added cyclohexanol through hydrodeoxygenation (HDO). In this work, a series of core-shell Co x @C@Ni catalysts were prepared via two-step hydrothermal and calcination treatments, and applied to catalyze guaiacol to cyclohexanol. Compared with Co@C catalyst, core-shell Co x @C@Ni catalysts exhibited much better catalytic performance. Almost 100% guaiacol conversion and 90% cyclohexanol selectivity were achieved over Co 1.2 @C@Ni catalyst at 220 °C, 0 MPa N 2 for 2 h using isopropanol as H-donor solvent, which was carried out under much milder conditions compared with previous research. The structure feature of core-shell Co x @C@Ni catalysts were analyzed by BET, XRD, SEM, TEM, HRTEM, etc. The catalyst compositions and acidities played a significant role on hydrodeoxygenation of guaiacol via ICP and NH 3 -TPD analysis. The influences of reaction temperature, reaction time and initial nitrogen pressure were also investigated to explore the optimal reaction condition. Moreover, the possible reaction pathways and reaction mechanism was deduced based on the product distributions and physicochemical properties. Core-shell Cox@C@Ni catalysts were synthesized for catalytic hydrodeoxygenation of guaiacol to generate cyclohexanol under mild condition. [Display omitted] • Guaiacol can be effectively converted into cyclohexanol over core-shell Cox@C@Ni catalysts. • The highest 90% cyclohexanol yield was obtained over Co1.2@C@Ni at 220 ℃, 0 MPa N2 for 2 h. • The synergetic effect of Co and Ni and the acidity of catalysts play an important role in the HDO of guaiacol. • A possible reaction mechanism of hydrogenation process was studied. [ABSTRACT FROM AUTHOR]

Electroreduction of nitrate (NO 3 -) to value-added ammonia (NH 3) provides an alternative to NH 3 production industry and remediation of NO 3 --containing wastewater. This study reports a series of Cu-Ni catalysts with component-controllable Cu x Ni y nanoparticles encapsulated in N-doped carbon film (Cu x Ni y /NC), and disclosure of the associated mechanism for NO 3 - reduction reaction (NO 3 -RR). Cu 0.43 Ni 0.57 /NC achieves a better NO 3 --N removal proportion of 89% in comparison with the reference catalysts, including Cu/NC (73%) and Cu x Ni y /NC with other compositions (Cu 0.79 Ni 0.21 /NC, 83%; Cu 0.26 Ni 0.74 /NC, 62%; Ni/NC, 20%). The experimental results and density functional theory calculations demonstrate that the lowered energy barriers of *NO 2 -to-*NO derived from appropriate Ni atom alloying plays a key role in the enhanced catalytic activity. Auxiliary porous substrate further contributes to the exposure of active sites and the durability of catalyst structure. These findings offer a mechanistic understanding of catalyst structure on the NO 3 -RR activity and valuable insights toward rational design of other catalysts for enhanced NO 3 -RR. [Display omitted] • A series of Cu x Ni y /NC catalysts were prepared for electroreduction of nitrate. • The optimized Cu 0.43 Ni 0.57 /NC shows efficient catalytic activity and durability. • The introduction of Ni alleviates NO 2 - accumulation compared with pure Cu. • Ni atom alloying lowers the energy barriers from *NO 2 to *NO proved by DFT. [ABSTRACT FROM AUTHOR]