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Flash Joule heating (FJH) is an emerging and profitable technology for converting inexhaustible biomass into flash graphene (FG). However, it is challenging to produce biomass FG continuously due to the lack of an integrated device. Furthermore, the high-carbon footprint induced by both excessive energy allocation for massive pyrolytic volatiles release and carbon black utilization in alternating current-FJH (AC-FJH) reaction exacerbates this challenge. Here, we create an integrated automatic system with energy requirement-oriented allocation to achieve continuous biomass FG production with a much lower carbon footprint. The programmable logic controller flexibly coordinated the FJH modular components to realize the turnover of biomass FG production. Furthermore, we propose pyrolysis-FJH nexus to achieve biomass FG production. Initially, we utilize pyrolysis to release biomass pyrolytic volatiles, and subsequently carry out the FJH reaction to focus on optimizing the FG structure. Importantly, biochar with appropriate resistance is self-sufficient to initiate the FJH reaction. Accordingly, the medium-temperature biochar-based FG production without carbon black utilization exhibited low carbon emission (1.9 g CO 2 -eq g -1 graphene), equivalent to a reduction of up to ~86.1% compared to biomass-based FG production. Undoubtedly, this integrated automatic system assisted by pyrolysis-FJH nexus can facilitate biomass FG into a broad spectrum of applications., (© 2024. The Author(s).)

The aim of this study is to investigate the potential of using marine sponge Hymeniacidon perleve to remove total organic carbon (TOC) in integrated aquaculture ecosystems. In sterilized natural seawater (SNSW) with different concentrations of TOC, H. perleve removed approximately 44-61% TOC during 24 h, with retention rates of ca. 0.19-1.06 mg/h .g-fresh sponge, however no particulate selectivity was observed. The highest initial TOC concentration, in which about 2.7 g fresh sponges could remove TOC effectively in 0.5-L SNSW, is 214.3-256.9 mg/L. The highest capacity of TOC removal and clearance rate (CR) by H. perleve is ca. 25.50 mg-TOC/g-fresh sponge and 7.64 mL/h . g-fresh sponge within 24 h, respectively. Until reaching the highest TOC removal capacity, the TOC removal capacity and clearance rate of H. perleve increased with initial TOC concentration, and dropped dramatically thereafter. After reaching the highest removal capacity, H. perleve could only remove relatively lower TOC concentration in seawater in subsequent run. The TOC removal kinetics in SNSW by H. perleve fitted very well with a S-shaped curve and a Logistic model equation (R(2) = 0.999). In different volumes of SNSW with a fixed initial TOC concentration, the weight/volume ratio of sponge biomass and SFNSW was optimized at 1.46 g-fresh sponge/1-L SNSW to achieve the maximum TOC removal. When co-cultured with marine fish Fugu rubripes for 15 days, H. perleve removed TOC excreted by F. rubripes with similar retention rates of ca. 0.15 mg/h . g-fresh sponge, and the sponge biomass increased by 22.8%., ((c) 2007 Wiley Periodicals, Inc.)

Biomass‐derived pyrogenic carbon is attractive for advanced oxidation processes (AOPs); however, its amorphous structure limits its activation efficiency. Graphene with highly conjugated π structure possesses superior electron transport ability and thus high usefulness. However, bygone strategies are scarcely effective for reforming pyrogenic carbon to graphene. Herein, for the first time, a state‐of‐the‐art flash Joule heating (FJH) technique is showcased for reforming pyrogenic carbon to 2–5‐layer graphene. FJH current‐induced ultrahigh temperature and stress field realize instantaneous (≈10 s) regeneration of pyrogenic carbon via synchronization actions of carbonization, graphitization, and exfoliation. Meanwhile, volatilization of doped N atoms accelerates graphitization but has less of an effect on graphene configuration. Accordingly, tuned oxygen groups at the graphene edge boost peroxydisulfate (PDS) adsorption for finer initiating activation. Subsequently, 2D graphene with excellent electron utilization rate strengthens hydroxyl radical and direct electron transfer pathways in activating PDS for sulfamethoxazole (SMX) degradation. Impressively, the SMX degradation efficiency by fabricated graphene raises ≈8.9‐fold as compared with pristine pyrogenic carbon. Additionally, fabricated graphene is more efficient in PDS activation than commercial metal catalysts. Undoubtedly, this study realizes effective transformation of pyrogenic carbon to graphene for highly efficient metal‐free carbocatalyst. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts have drawn great attention, especially in electrocatalysis. However, most of previous works focus on the enhanced catalytic properties via improving metal loading. Engineering morphologies of catalysts to facilitate mass transport through catalyst layers, thus increasing the utilization of each active site, is regarded as an appealing way for enhanced performance. Herein, we design an overhang‐eave structure decorated with isolated single‐atom iron sites via a silica‐mediated MOF‐templated approach for oxygen reduction reaction (ORR) catalysis. This catalyst demonstrates superior ORR performance in both alkaline and acidic electrolytes, comparable to the state‐of‐the‐art Pt/C catalyst and superior to most precious‐metal‐free catalysts reported to date. This activity originates from its edge‐rich structure, having more three‐phase boundaries with enhanced mass transport of reactants to accessible single‐atom iron sites (increasing the utilization of active sites), which verifies the practicability of such a synthetic approach. [ABSTRACT FROM AUTHOR]

Engineering p–n heterojunctions among metal oxide semiconductors to provide a built‐in electric field is an efficient strategy to facilitate the separation of photogenerated electrons and holes and improve their photocatalytic activities. However, the inherent poor conductivity of p–n heterojunctions still limits the charge‐transfer step and thus hampers their practical application in photocatalysis. In this work, a nitrogen‐doped carbon‐coated NiO/TiO2 p–n (NCNT) heterojunction with hierarchical mesoporous sphere morphology was synthesized by in situ pyrolytic decomposition of nickel–titanium complexes. The NiO/TiO2 p–n heterojunction in NCNT was fully characterized by several techniques, supported by theoretical calculations and Mott–Schottky plots. On coating with a thin nitrogen‐doped carbon layer, the electron transfer of the obtained p–n heterojunction could be significantly enhanced. On account of the favorable structural features of the p–n heterojunction with nitrogen‐doped carbon coating and hierarchical mesoporous structure, NCNT exhibited excellent photocatalytic activity toward various reaction systems, including the hydrogen evolution reaction and the visible‐light‐induced hydroxylation of phenylboronic acids. [ABSTRACT FROM AUTHOR]

Multicomponent NiTiO3/A‐TiO2/R‐TiO2 photocatalysts coated with nitrogen‐doped carbon (N‐C/NiTiO3/A‐TiO2/R‐TiO2) for efficient H2 production were fabricated by directly pyrolyzing NH2‐MIL‐125(Ni/Ti) metal–organic framework microrods. Owing to the synergistic effect of the N‐doped carbon coating layer and multicomponent heterojunctions, the H2 production rate of N‐C/NiTiO3/A‐TiO2/R‐TiO2 was even higher than that of its Pt‐containing counterpart (Pt/NiTiO3/A‐TiO2/R‐TiO2). N‐C/NiTiO3/A‐TiO2 and N‐C/NiTiO3/R‐TiO2 as control photocatalysts were also prepared by simply adjusting the calcination temperature of NH2‐MIL‐125(Ni/Ti) in air atmosphere. The H2 production rate followed the order of N‐C/NiTiO3/A‐TiO2/R‐TiO2>N‐C/NiTiO3/A‐TiO2>N‐C/NiTiO3>R‐TiO2, which indicates that the multicomponent heterojunction plays a key role in photocatalytic H2 generation. The mechanism for the influence of the multicomponent heterojunction on photocatalytic activity was investigated in combination with molecular simulations, which showed that N‐C/NiTiO3/A‐TiO2/R‐TiO2 has a so‐called double type II heterojunction providing a perfect step‐by‐step migration pathway for effective separation of photogenerated electrons and holes. This work presents a simple and effective method for synthesizing efficient multicomponent photocatalysts. [ABSTRACT FROM AUTHOR]

• TiO 2 -based photocatalysts loaded with two interfacial co-catalysts are prepared. • Interface sequence of N-doped carbon layer and Au nanoparticles are engineered. • Direct Au/TiO 2 interface enhances the separation efficiency of electrons/holes. • N-Doped C layer on Au/TiO 2 interface achieves a synergistic effect in H 2 production. Multicomponent photocatalysts loaded with two interfacial co-catalysts may exhibit greater improvement in hydrogen evolution than those without any co-catalyst or with only one co-catalyst. Two major issues should be solved in developing such photocatalysts. One is how to obtain photocatalysts with two interfacial co-catalysts by a controllable approach. The other is what are key factors affecting photocatalytic activity. In this study, TiO 2 -based photocatalysts loaded with two interfacial co-catalysts, i.e., N-doped carbon layer coating on Au nanoparticle-embedded TiO 2 and Au nanoparticles attaching on N-doped carbon layer coated TiO 2 , were prepared by thermal degradation of a Ti-based metal-organic framework, where the composition and interface sequence of N-doped carbon layer and Au nanoparticles were carefully engineered. Experimental results conclude that the Au/TiO 2 interface, formed by a direct contact between Au and TiO 2 , is key factor to enhance the separation efficiency of photogenerated electrons/holes, and coating N-doped carbon layer on this Au/TiO 2 interface achieves a synergistic effect in enhancing photocatalytic H 2 production. [ABSTRACT FROM AUTHOR]

Titelbild: Single-Atom Iron Catalysts on Overhang-Eave Carbon Cages for High-Performance Oxygen Reduction Reaction (Angew. Keywords: electrochemistry; metal-organic frameworks; oxygen reduction reaction; single-atom catalysis; transition metals EN electrochemistry metal-organic frameworks oxygen reduction reaction single-atom catalysis transition metals 7341 7341 1 04/24/20 20200504 NES 200504 B Ein traufenförmiger Kohlenstoffkäfig b , der mit einem Einzelatom-Eisenkatalysator für die Sauerstoffreduktion (ORR) dekoriert ist, wurde mithilfe eines Silica-vermittelten MOF-templatierten (SMMT) Ansatzes hergestellt, den Q. Xu und Mitarbeiter in ihrer Zuschrift auf S. 7454 beschreiben. Electrochemistry, metal-organic frameworks, oxygen reduction reaction, single-atom catalysis, transition metals. [Extracted from the article]