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The electrochemical reductive cleavage of the C–O bond in the lignin α-O-4 model compound benzyl phenyl ether (BPE) at room temperature was investigated using earth-abundant nickel as a catalyst in methanol. Experiments using a divided cell setup using either NiCl2·6H2O salt or pre-deposited Ni on a carbon paper cathode (Ni/CP) under an inert atmosphere revealed the essential role of freshly and uniformly deposited Ni0 on the electrode surface for the reductive, catalytic cleavage to yield phenol and toluene. To better understand the reaction mechanism, the surface morphology and composition of the Ni/CP electrode were investigated by SEM, XRD, and XPS. Additionally, the role of methanol as a proton donor was established, and electrochemical hydrogenation/hydrogenolysis (ECH) experiments of BPE with sterically hindered substituents revealed that the reaction mechanism shares similarities with Pd/C hydrogenation/hydrogenolysis chemistry. DFT calculations further supported this mechanistic route and were consistent with the experimental observations. Based on both experimental and calculation results, a mechanism including (1) the interaction of the benzylic side of BPE with the catalyst surface, (2) adsorbed hydrogen interacting with the benzylic carbon to induce C–O bond scission, and (3) proton transfer to the phenoxy anion from the methanol was proposed. [ABSTRACT FROM AUTHOR]

The development of an active earth-abundant metal electrocatalyst for biomass-derived organic materials valorization can greatly benefit the growth of a sustainable biorefinery. Herein, we report a transition metal dichalcogenide catalyst, MoS2, as a great electrocatalytic hydrogenation catalyst in converting a highly versatile platform chemical furfural to furfuryl alcohol, with over 82.4% yield and 92.1% selectivity, and its catalytic performance surpassed those of 11 other base metal electrocatalysts. The durable layer of 1T-rich MoS2 was fabricated on a carbon cloth support via a novel seeded-solvothermal deposition, followed by a thermal treatment. Reaction mechanistic investigation via underpotential hydrogen desorption (HUPD) studies and substrate scope expansion showed that MoS2 delivered the mechanism in a stage-wise manner, where the reduction of the carbonyl occurred to yield a radical intermediate in the vicinity of the MoS2 catalyst, followed by an abstraction of a surface adsorbed hydrogen (Hads). The conversion of reactants benefited from the presence of electron-withdrawing substituents, and the product selectivity was inert to the influence of the substituents. The MoS2 can be prepared easily through electrocatalytic and solvothermal deposition. The resulting catalyst layer demonstrated great stability throughout the repeated application in bulk electrolysis. [ABSTRACT FROM AUTHOR]

Sustainable production of valuable biochemicals and biofuels from lignocellulosic biomass necessitates the development of durable and high-performance catalysts. To assist the next stage catalyst design for hydrothermal treatment of biosugars, this paper provides a critical review of (1) recent advances in biosugar hydrothermal valorization using heterogeneous catalysts, (2) the deactivation process of catalysts based on recycling tests of representative biosugar hydrothermal treatments, (3) state-of-the-art understandings of the deactivation mechanisms of heterogeneous catalysts, and (4) strategies of preparing durable catalysts and the regeneration of deactivated catalysts. Based on the review, challenges and perspectives are proposed. Some remarkable achievements in heterogeneous catalysis of biosugars are highlighted. The understanding of catalyst durability needs to be further increased based on full examination of the catalytic performance based on the conversion of substrates, the yield and selectivity of products. Further, a full examination of the physiochemical changes based on multiple characterization techniques is required to illuminate the relationships between treatment variables and catalyst durability. Collectively, a clear understanding of the relationships between chemical reaction pathways, treatment variables and the physiochemistry of catalysts is encouraged to be gained to advise the development of heterogeneous catalysts for long-term and efficient hydrothermal upgrading of biosugars., (© 2024 Wiley‐VCH GmbH.)

Many phenolic compounds (PhCs) in biomass burning and fossil fuel combustion emissions can partition into atmospheric aqueous phases ( e.g. , cloud/fog water and aqueous aerosols) and undergo reactions to form secondary organic aerosols (SOAs) and brown carbon (BrC). Redox-active transition metals, particularly Fe and Cu, are ubiquitous species in atmospheric aqueous phases known to participate in Fenton/Fenton-like chemistry as a source of aqueous ˙OH. However, even though the concentrations of water-soluble Cu are close to those of water-soluble Fe in atmospheric aqueous phases in some areas, unlike Fe, the effects that Cu have on SOA and BrC formation in atmospheric aqueous phases have scarcely been studied and remain poorly understood. We investigated the effects of Cu(II) on PhC reaction rates and BrC formation during the aqueous oxidation of four PhCs (guaiacol, catechol, syringol, and vanillin) by ˙OH generated from Fenton-like chemistry under different pH conditions. While the PhCs reacted when both H 2 O 2 and Cu(II) were present in the absence ( i.e. , dark oxidation) and presence ( i.e. , photooxidation) of light, the reaction rates were at least one order of magnitude higher during photooxidation. Higher PhC reaction rates were measured at higher pH during both dark oxidation and photooxidation as a result of higher ˙OH concentrations produced by Fenton-like chemistry. Only water-soluble BrC was formed during dark oxidation and photooxidation when Cu(II) was present. Mass absorption coefficients (10 3 to 10 4 cm 2 g -1 ) comparable to those of biomass burning BrC were measured during dark oxidation and photooxidation when Cu(II) was present. Light absorption was enhanced at higher pH during dark oxidation and photooxidation, which indicated that higher quantities and/or more absorbing BrC chromophores were formed at higher pH. The effects that Cu(II) had on the PhC reaction rates and the composition of SOAs and BrC formed depended on the PhC base structure ( i.e. , benzenediol vs. methoxyphenol). Overall, these results show how aqueous reactions involving Cu(II), H 2 O 2 , and PhCs can be an efficient source of daytime and nighttime water-soluble BrC and SOAs, which can have significant implications for how the atmospheric fates of PhCs are modeled for areas with substantial concentrations of water-soluble Cu in highly to moderately acidic cloud/fog water and aqueous aerosols.

Chemical mechanical polishing (CMP) offers a promising pathway to smooth third-generation semiconductors. However, it is still a challenge to reduce the use of additional oxidants or/and energy in current CMP processes. Here, a new and green atomically smoothing method: Piezocatalytic-CMP (Piezo-CMP) is reported. Investigation shows that the Piezo-CMP based on tetragonal BaTiO 3 (t-BT) can polish the rough surface of a reaction sintering SiC (RS-SiC) to the ultra-smooth surface with an average surface roughness (Ra) of 0.45 nm and the rough surface of a single-crystal 4H-SiC to the atomic planarization Si and C surfaces with Ra of 0.120 and 0.157 nm, respectively. In these processes, t-BT plays a dual role of piezocatalyst and abrasive. That is, it piezo-catalytically generates in-situ active oxygen species to selectively oxidize protruding sites of SiC surface, yielding soft SiO 2 , and subsequently, it acts as a usual abrasive to mechanically remove these SiO 2 . This mechanism is further confirmed by density functional theory (DFT) calculation and molecular simulation. In this process, piezocatalytic oxidation is driven only by the original pressure and friction force of a conventional polishing process, thus, the piezo-CMP process do not require any additional oxidant and energy, being a green and effective polishing method., (© 2023 Wiley‐VCH GmbH.)

Aim: To estimate the overall drug compliance for local Chinese glaucoma patients on long-term topical treatment., Methods: This was a retrospective cross-sectional study. Fifty-seven primary glaucoma patients from the subspecialty clinic of a publicly-funded tertiary care hospital in Hong Kong completed a questionnaire on compliance with topical glaucoma medication, attitude towards glaucoma and therapy and vision related quality of life. Noncompliance was defined as reporting missing more than or equal to 10% of the prescribed topical glaucoma medication during the 2wk immediately prior to the consultation. Relationships between noncompliance and demographics, attitude, disease and treatment status was studied. Cost was estimated with quality of life and direct medical cost involved with noncompliance. Multivariable logistic regression on noncompliance was performed on selected factors., Results: Compliance was calculated as 75% (95% CI: 64%-87%) among 57 subjects (mean age 69y, female 51%). No statistical significant relationship was established between noncompliance and any single factors or outcomes. Age ( P =0.048) and forgetfulness ( P =0.064) were found to be marginally significant predictive factors on noncompliance in multivariable logistic regression. Noncompliance might be related ( P =0.130) to poorer self-rated vision-associated quality of life. The societal cost of noncompliance was estimated to be over 2510 life-years and US$ 3.7 million territory-wide., Conclusion: The compliance of Chinese glaucoma patients in Hong Kong is comparable to other parts in the world, and carries detrimental impacts on individual and societal levels. Age and forgetfulness are two possible independent predictors for noncompliance.