Solar‐driven interfacial evaporation is an important approach for solving the issue of freshwater scarcity. However, the practical application of solar steam generation is hindered by high fabrication cost and environmental concerns regarding the petroleum‐based materials. Herein, lignocellulose (cellulose‐lignin composite) hydrogel (LCG) and lignin‐derived carbon (LC) are used as the substrate and photothermal material, respectively, to construct a fully lignocellulose‐based double‐layered hydrogel (LC@LCG) evaporator. Results indicate that LC has an ultrahigh specific surface area and full‐spectrum solar absorption of 98%. The presence of lignin can improve the hydrophilicity and maintain the capillary channels of the hydrogel, which tunes water into an intermediate state and reduces the vaporization enthalpy of water. Moreover, it ensures a high water transport rate in the hydrogel. Based on these advantages, the evaporation rate and photothermal conversion efficiency of hydrogel evaporator reach 1.84 kg m−2 h−1 under one sun and 86.5%, respectively. The lignocellulosic hydrogel evaporator could remove >99.95% of primary metal ions from seawater to generate fresh water, and shows outstanding salt resistance, durability, and long‐term stability for desalination. This study demonstrates an eco‐friendly and economic solution for continuous freshwater production from seawater using a fully lignocellulosic biomass‐based hydrogel evaporator.

Fully Lignocellulosic Biomass‐Based Double‐Layered Porous Hydrogel for Efficient Solar Steam Generation

Solvent-induced molecular structure engineering of lignin for hierarchically porous carbon: Mechanisms and supercapacitive properties

NiO nanocrystal anchored on pitaya peel-derived carbon laminated mesoporous composites for the electrocatalytic oxidation of ethanol

5-hydroxymethylfurfural (HMF), as one of the top ten important platform chemicals, can be used to produce 2,5-furandicarboxylic acid (FDCA), 2,5-dimethyl furan (DMF), levulinic acid, and other chemicals. An environmentally friendly system for the synthesis of sulfonated carbon materials from discarded masks has been proposed. A series of mask-based solid acid catalysts (bMC-SO3H) were prepared by a simple two-step process. Mechanochemical pretreatment (ball milling) of waste mask and sulfonated group precursor, followed by thermal carbonization under nitrogen gas, were used to synthesize sulfonated porous carbon. The total acid amount of the prepared bMC-SO3H was measured by the Boehm method, which exhibited 1.2–5.3 mmol/g. The addition of the sulfonated group precursor in the mechanochemical treatment (ball milling) process caused intense structure fragmentation of the discarded masks. These sulfonated porous carbons (bMC(600)-SO3H) as solid acid catalysts achieved fructose conversion of 100% and HMF yield of 82.1% after 120 min at 95 °C in 1-butyl-3-methylimidazolium chloride. The bMC-SO3H could be reused five times, during which both the HMF yield and fructose conversion were stable. This work provides a strategy for the synthesis of sulfonated carbon from discarded masks and efficient catalyzed fructose upgrading to HMF.

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Synthesis of Sulfonated Carbon from Discarded Masks for Effective Production of 5-Hydroxymethylfurfural

Rational design of efficient, stable, and inexpensive bifunctional electrocatalysts for oxygen evolution reactions (OER) and hydrogen evolution reactions (HER) is a key challenge to realize green hydrogen production via electrolytic water splitting. Herein, Ru nanoparticles andFeNi alloy heterojunction catalyst (Ru-FeNi@NLC)encapsulated via lignin-derived carbon was prepared by self-assembly precipitation and in situ pyrolysis. The designed catalyst displays excellent performance at 10 mA cm-2with low overpotentials of 36 mV for HER and 198 mV for OER, and only needs 1.48 V for overall water splitting. Results and DFT calculations show the unique N-doped lignin-derived carbon layer and Ru-FeNi heterojunction contribute to optimized electronic structure for enhancing electron transfer, balanced free energy of reactants and intermediates in the sorption/desorption process, and significantly reduced reaction energy barrier for the HER and OER rate-determining steps,thus improved reaction kinetics. This work provides a new in situ pyrolysis doping strategy based on renewable biomass for the construction of highly active, stable and cost-effectivecatalysts.

Ru-FeNi Alloy Heterojunctions on Liginin-derived Carbon as Bifunctional Electrocatalysts for Efficient Overall Water Splitting.

The conversion of renewable bioethanol into high-energy-density higher alcohols has become essential for meeting the increasing global demand to achieve carbon neutrality. In this study, Zn- and nitrogen-codoped Ni-based lignin-derived carbon catalysts (NiZn@NC) were prepared by solvent volatile self-assembly and in situ reductive carbonization using pulp and paper waste stream alkali lignin as the carbon source. Lignin amphipathic derivatives with −COOH and −NH2 groups would coordinate with metal ions to form a stable lignin–metal framework; thus, the lignin-derived carbon layer disperses the NiZn bimetallic catalyst and prevents from corroding. At an amination reagent/lignin mass ratio of 1:2, an ethanol conversion of 75.2% and a high alcohol yield of 41.7% were achieved over the Ni20Zn1@NC catalyst. Experimental results and density functional theory calculations showed that Zn doping improved the electronic environment and defect structures of metallic Ni and carbon carrier, which effectively inhibited C–C cleavage and suppressed the byproduct formation, such as methane. Thereby, the synergetic effect between Ni and Zn facilitated the efficient conversion of aqueous ethanol into higher alcohols by the Guerbet reaction. This work provides a strategy of in situ pyrolytic doping and stabilizing of renewable biomass macromolecules as the frameworks for the construction of highly active and cost-efficient catalysts for ethanol upgrading. 

Efficient Catalytic Upgrading of Ethanol to Higher Alcohols via Inhibiting C–C Cleavage and Promoting C–C Coupling over Biomass-Derived NiZn@NC Catalysts

Quanzhou Xu

Papers

Efficient Catalytic Upgrading of Ethanol to Higher Alcohols via Inhibiting C–C Cleavage and Promoting C–C Coupling over Biomass-Derived NiZn@NC Catalysts