Lignin is a major component of lignocellulosic biomass. Although it is highly recalcitrant to break down, it is a very abundant natural source of valuable aromatic carbons. Thus, the effective ...valorisation of lignin is crucial for realising a sustainable biorefinery chain. Here, we report a compartmented photo-electro-biochemical system for unassisted, selective, and stable lignin valorisation, in which a TiO
photocatalyst, an atomically dispersed Co-based electrocatalyst, and a biocatalyst (lignin peroxidase isozyme H8, horseradish peroxidase) are integrated, such that each system is separated using Nafion and cellulose membranes. This cell design enables lignin valorisation upon irradiation with sunlight without the need for any additional bias or sacrificial agent and allows the protection of the biocatalyst from enzyme-damaging elements, such as reactive radicals, gas bubbles, and light. The photo-electro-biochemical system is able to catalyse lignin depolymerisation with a 98.7% selectivity and polymerisation with a 73.3% yield using coniferyl alcohol, a lignin monomer.
•Surface shielding of inorganic photocatalyst by hydrophobic organic photocatalyst.•Restrict the self-oxidation of photogenerated H2O2, and maximize the H2O2 production.•A potential strategy for ...sustainable H2O2 production from natural resources (sun, water, and air).•The atomistic simulation studies substantiate the hydrophobicity induced H2O2 production.•A facile yet effective approach for solar H2O2 production over inorganic/organic heterojunction.
Photocatalytic H2O2 production is one of the most promising methods because it is a safe and sustainable technique. However, the inactiveness of inorganic photocatalysts (TiO2) under visible light irradiation and severe photodecomposition of H2O2 on their surfaces result in low performance for solar H2O2 production. Here, we report for the first time, a hydrophobic organic/inorganic (polymer/TiO2) heterojunction photocatalyst, which not only can utilize visible light, but also suppress H2O2 decomposition. In the absence of a hole scavenger, the photogenerated H2O2 concentration of the poly(9,9-dioctylfluorene-alt-benzothiadiazole) (PFBT)/TiO2 heterojunction photocatalyst (67 µM) was >70 times higher than that of pristine PFBT polymer. Further, improvement of polymer hydrophobicity by fluorine substitution results in enhanced photogenerated H2O2 concentration (110.4 µM) on (Poly(9,9-dioctyl fluorine-alt-difluorobenzothiadiazole) (PF2FBT)/TiO2). The atomistic simulation studies substantiate that the low adsorption energy of H2O2 on the heterojunction and the surface shielding of TiO2 induced by the hydrophobicity of the fluorinated polymers significantly improve H2O2 production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The importance of hydrogen peroxide (H2O2) continues to grow globally. Deriving the oxygen reduction reaction (ORR) toward the 2e– pathway to form H2O2 is crucial for high H2O2 productivity. However, ...most selective electrocatalysts following the 2e– pathway comprise carbon‐containing organic materials with intrinsically low stability, thereby limiting their commercial applicability. Herein, layered double hydroxides (LDHs) are used as inorganic matrices for the first time. The LDH catalyst developed herein exhibits near‐100% 2e– ORR selectivity and stably produces H2O2 with a concentration of ≈108.2 mm cm–2photoanode in 24 h in a two‐compartment system (with a photoanode) with a solar‐to‐chemical conversion efficiency of ≈3.24%, the highest among all reported systems. Density functional theory calculations show that 2e– ORR selectivity is promoted by atomically dispersed cobalt atoms in (012) planes of the LDH catalyst, while a free energy gap between the *O and OOH– states is an important factor.
A highly 2e– oxygen reduction pathway‐selective layered double hydroxide (LDH) catalyst is proposed to increase the yield of H2O2 production. A two‐compartment photoelectrochemical system with the catalyst can catalyze H2O2 generation with concentrations of ≈108.2 mm cm–2 in 24 h without any external bias. A solar‐to‐chemical conversion efficiency of ≈3.24% is recorded, which is the highest efficiency among those of all reported systems.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Solar Hydrogen Peroxide Production
In article number 2110412, Hu Young Jeong, Changduk Yang, Jun Hee Lee, Ji‐Wook Jang, Seungho Cho, and co‐workers report a highly two‐electron oxygen‐reduction ...pathway‐selective layered double hydroxide catalyst for hydrogen peroxide production. A bias‐free two‐compartment photoelectrochemi cal system with the catalyst can generate hydrogen peroxide with a solar‐to‐hydrogen peroxide conversion efficiency of 3.24%.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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