Electrochemical reduction of biomass-derived 5-hydroxymethylfurfural (HMF) represents an elegant route toward sustainable value-added chemicals production that circumvents the use of fossil fuel and hydrogen. However, the reaction efficiency is hampered by the high voltage and low activity of electrodes (Cu, Bi, Pb). Herein, we report a Ru 1 Cu single-atom alloy (SAA) catalyst with isolated Ru atoms on Cu nanowires that exhibits an electrochemical reduction of HMF to 2,5dihydroxymethylfuran (DHMF) with promoted productivity (0.47 vs. 0.08 mmol cm À 2 h À 1 ) and faradic efficiency (FE) (85.6 vs. 71.3 %) at À 0.3 V (vs. RHE) compared with Cu counterpart. More importantly, the FE (87.5 %) is largely retained at high HMF concentration (100 mM). Kinetic studies by using combined electrochemical techniques suggest disparate mechanisms over Ru 1 Cu and Cu, revealing that single-atom Ru promotes the dissociation of water to produce H* species that effectively react with HMF via an electrocatalytic hydrogenation (ECH) mechanism.

Oxidative cleavage of C(OH)ÀCb onds to afford carboxylates is of significant importance for the petrochemical industry and biomass valorization. Here we report an efficient electrochemical strategy for the selective upgrading of lignin derivatives to carboxylates by am anganese-doped cobalt oxyhydroxide (MnCoOOH) catalyst. Awide range of ligninderived substrates with C(OH)-C or C(O)-C units undergo efficient cleavage to corresponding carboxylates in excellent yields (80-99 %) and operational stability (200 h). Detailed investigations reveal atandem oxidation mechanism that base from the electrolyte converts secondary alcohols and their derived ketones to reactive nucleophiles,which are oxidized by electrophilic oxygen species on MnCoOOH from water.A s proof of concept, this approachwas applied to upgrade lignin derivatives with C(OH)-C or C(O)-C motifs,a chieving convergent transformation of lignin-derived mixtures to benzoate and KA oil to adipate with 91.5 %a nd 64.2 %y ields, respectively.

Hydrogen production via electrochemical water splitting is one of the most green and promising ways to produce clean energy and address resource crisis, but still suffers from low efficiency and high cost mainly due to the sluggish oxygen evolution reaction (OER) process. Alternatively, electrochemical hydrogen-evolution coupled with alternative oxidation (EHCO) has been proposed as a considerable strategy to improve hydrogen production efficiency combined with the production of high value-added chemicals. Although with these merits, high-efficient electrocatalysts are always needed in practical operation. Typically, layered double hydroxides (LDHs) have been developed as a large class of advanced electrocatalysts toward both OER and EHCO with high efficiency and stability. In this review, we have summarized the latest progress of hydrogen production from the perspectives of designing efficient LDHs-based electrocatalysts for OER and EHCO. Particularly, the influence of structure design and component regulation on the efficiency of their electrocatalytic process have been discussed in detail. Finally, we look forward to the challenges in the field of hydrogen production via electrochemical water splitting coupled with organic oxidation, such as the mechanism, selected oxidation as well as system design, hoping to provide certain inspiration for the development of low-cost hydrogen production technology.

Adipic acid is an important building block of polymers, and is commercially produced by thermo-catalytic oxidation of ketone-alcohol oil (a mixture of cyclohexanol and cyclohexanone). However, this process heavily relies on the use of corrosive nitric acid while releases nitrous oxide as a potent greenhouse gas. Herein, we report an electrocatalytic strategy for the oxidation of cyclohexanone to adipic acid coupled with H2 production over a nickel hydroxide (Ni(OH)2) catalyst modified with sodium dodecyl sulfonate (SDS). The intercalated SDS facilitates the enrichment of immiscible cyclohexanone in aqueous medium, thus achieving 3.6-fold greater productivity of adipic acid and higher faradaic efficiency (FE) compared with pure Ni(OH)2 (93% versus 56%). This strategy is demonstrated effective for a variety of immiscible aldehydes and ketones in aqueous solution. Furthermore, we design a realistic two-electrode flow electrolyzer for electrooxidation of cyclohexanone coupling with H2 production, attaining adipic acid productivity of 4.7 mmol coupled with H2 productivity of 8.0 L at 0.8 A (corresponding to 30 mA cm−2) in 24 h.

Fischer−Tropsch synthesis (FTS) is a significant catalytic process for the production of liquid fuel and fine chemicals from natural gas-, coal-, and biomass-derived syngas. However, exploring high-performance catalysts and understanding the catalytic mechanism remain challenging. Herein, we design a Ru 1 Co n single-atom alloy (SAA) catalyst with isolated Ru atoms anchored onto a Co nanoparticle surface through a twodimensional confinement strategy to achieve greatly improved FTS activity (2.6 mol CO mol M −1 h −1 ) and long-chain hydrocarbon selectivity (C 5 + : 86.0%) at a low reaction temperature of 150 °C. A series of in situ experiments, catalytic tests, and density functional theory (DFT) calculations reveal that the Ru single-atom sites in Ru 1 Co n SAA are more active for the FTS reaction than pure Ru and Co surfaces. This is because single-atom Ru with a much higher electronic density near the Fermi level could effectively and simultaneously decrease the rate-limiting barriers of both C−O splitting and chain growth processes. This work demonstrates the possibility of designing Ru single-atom sites to improve FTS performance and provides a deeper understanding of the strategy for developing other high-performance industrial catalysts.

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The multiproduct upgrade of ethanol and acetaldehyde to butadiene as a high-value chemical and butanol as a biofuel was investigated over the Y–SiO2 heterogeneous catalysts. The sum selectivity of butanol and butadiene is over 90% for the Y–SiO2 catalysts with Y/Si ratios from 0.05 to 0.35, while the distribution changes with the Y/Si ratio. The highest butadiene selectivity of 81.2% with a butanol selectivity of 10.3% was obtained over the Y–SiO2 catalyst with a Y/Si ratio of 0.05. To study the effect of the catalyst structure and acid–base property on catalytic performance, the Y–SiO2 catalysts with different Y/Si ratios were further comprehensively characterized by techniques including nitrogen adsorption–desorption, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), 29Si cross–polarization/magic-angle spinning nuclear magnetic resonance (29Si CP MAS NMR), Fourier transform infrared resonance (FTIR), UV–Vis diffuse reflectance spectra (UV–Vis DRS), temperature-programmed desorption of NH3 and CO2 and NH3 (NH3-TPD and CO2-TPD), and FTIR spectroscopy of adsorbed pyridine (Pyridine-IR). Results from XPS, 29Si CP MAS NMR, FTIR, and UV–Vis DRS reveal the electron transfer and the formation of chemical linkages between Y2O3 and SiO2 rather than the simple deposition of Y2O3 on the surface of the fumed silica. What is more, the amounts and coordination of Y–O–Si linkages on the surface of the fumed silica vary with the Y/Si ratio varying, thus resulting in variation of the acid–base property. Combining with the catalytic activity, NH3-TPD, CO2-TPD, and Pyridine-IR results indicate that the strength of acid and base sites has a significant role on the catalytic performance. The base sites with stronger strength contribute to the formation of butanol. To obtain a high butadiene selectivity, a balance of the acid–base property is necessary. A combination of Y3+ Lewis acid sites with a higher density ratio of stronger acid sites to the total acid sites and base sites with an intermediate strength is inclined toward a high butadiene selectivity. It means that a proper distribution between butadiene and butanol could be achieved by tuning the acid–base property of theY–SiO2 catalysts on the premise of a high C4 selectivity of over 90%.

Aimed at efficient production of 5-hydroxymethylfurfural (HMF) in a green and sustainable way, dehydrogenation of fructose was enhanced by liquid–liquid extraction in a membrane dispersion microreactor. On account of the high mass-transfer rate resulted from dripping flow, the obtained HMF was readily extracted from the aqueous phase to the organic phase, effectively preventing the sequence side reaction and leading to high HMF selectivity. Enhanced by efficient extraction, the reaction duration decreased from 60 min in a traditional stirred reactor to 4 min in the microreactor, leading to an increase in the space-time yield by 3 orders of magnitude. The effects of total volume flow rate, droplet size, and phase ratio relating to extraction efficiency and HMF yield were systematically investigated. The highest extraction efficiency of nearly 100% coupled with the HMF yield of 93.0% was achieved at the phase ratio of 2 with volume flow rate of 600 mL/h. Overall, this work not only delineates an efficient strategy for synthesizing HMF but also opens a new avenue for reaction systems with subsequent side reaction, which suffer from low selectivity of the intermediates due to the in-line separation bottleneck under conditions of limited mass transfer.