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Limited charge separation/transport efficiency remains the primary obstacle of achieving satisfying photoelectrochemical (PEC) water splitting performance. Therefore, it is essential to develop diverse interfacial engineering strategies to mitigate charge recombination. Despite obvious progress having been made, most works only considered a single‐side modulation in either the electrons of conduction band or the holes of valence band in a semiconductor photoanode, leading to a limited PEC performance enhancement. Beyond this conventional thinking, we developed a novel coupling modification strategy to achieve a composite electrode with bidirectional carrier transport for a better charge separation, in which Ti2C3Tx MXene quantum dots (MQDs) and α‐Fe2O3 nanodots (FO) are anchored on the surface of ZnIn2S4 (ZIS) nanoplates, resulting in markedly improved PEC water splitting of pure ZIS photoanode. Systematic studies indicated that the bidirectional charge transfer pathways were stimulated due to MQDs as "electron extractor" and S−O bonds as carriers transport channels, which synergistically favors significantly enhanced charge separation. The enhanced kinetic behavior at the FO/MQDs/ZIS interfaces was systematically and quantitatively evaluated by a series of methods, especially scanning photoelectrochemical microscopy. This work may deepen our understanding of interfacial charge separation, and provide valuable guidance for the rational design and fabrication of high‐performance composite electrodes. [ABSTRACT FROM AUTHOR]

Depositing a transition‐metal hydroxide (TMH) layer on a photoanode has been demonstrated to enhance photoelectrochemical (PEC) water oxidation. However, the controversial understanding for the improvement origin remains a key challenge to unlock the PEC performance. Herein, by taking BiVO4/iron‐nickel hydroxide (BVO/FxN4−x‐H) as a prototype, we decoupled the PEC process into two processes including charge transfer and surface catalytic reaction. The kinetic information at the BVO/FxN4−x‐H and FxN4−x‐H/electrolyte interfaces was systematically evaluated by employing scanning photoelectrochemical microscopy (SPECM), intensity modulated photocurrent spectroscopy (IMPS) and oxygen evolution reaction (OER) model. It was found that FxN4−x‐H acts as a charge transporter rather than a sole electrocatalyst. PEC performance improvement is mainly ascribed to the efficient suppression of charge recombination by fast hole transfer kinetics at BVO/FxN4−x‐H interface. [ABSTRACT FROM AUTHOR]

Depositing a transition‐metal hydroxide (TMH) layer on a photoanode has been demonstrated to enhance photoelectrochemical (PEC) water oxidation. However, the controversial understanding for the improvement origin remains a key challenge to unlock the PEC performance. Herein, by taking BiVO4/iron‐nickel hydroxide (BVO/FxN4−x‐H) as a prototype, we decoupled the PEC process into two processes including charge transfer and surface catalytic reaction. The kinetic information at the BVO/FxN4−x‐H and FxN4−x‐H/electrolyte interfaces was systematically evaluated by employing scanning photoelectrochemical microscopy (SPECM), intensity modulated photocurrent spectroscopy (IMPS) and oxygen evolution reaction (OER) model. It was found that FxN4−x‐H acts as a charge transporter rather than a sole electrocatalyst. PEC performance improvement is mainly ascribed to the efficient suppression of charge recombination by fast hole transfer kinetics at BVO/FxN4−x‐H interface. [ABSTRACT FROM AUTHOR]

Gold clusters loaded on various supports have been widely used in the fields of energy and biology. However, the poor photostability of Au clusters on support interfaces under prolonged illumination usually results in loss of catalytic performance. Covalent organic frameworks (COFs) with periodic and ultrasmall pore structures are ideal supports for dispersing and stabilizing Au clusters, although it is difficult to encapsulate Au clusters in the ultrasmall pores. In this study, a two‐dimensional (2D) COF modified with thiol chains in its pores was prepared. With −SH groups as nucleation sites, Au nanoclusters (NCs) could grow in situ within the COF. The ultrasmall pores of the COF and the strong S−Au binding energy combine to improve the dispersibility of Au NCs under prolonged light illumination. Interestingly, Au–S–COF bridging as observed in this artificial Z‐scheme photocatalytic system is deemed to be an ideal means to increase charge‐separation efficiency. [ABSTRACT FROM AUTHOR]

By a facile peripheral decoration of 5‐(4‐aminophenyl)‐10,15,20‐triphenylporphyrin (ATPP) with inherent aggregation‐induced emission (AIE) active tetraphenylethene (TPE), a versatile AIEgenic porphyrin derivative (ATPP‐TPE) was obtained, which greatly abolishes the detrimental π–π stacking and thus surmounts the notorious aggregation‐caused quenching (ACQ) effect of ATPP in aqueous phase. The photoluminescence of ATPP‐TPE is 4.5‐fold stronger than ATPP at aggregation state. Moreover, an unequivocal aggregation induced electrochemiluminescence (AIECL) of ATPP‐TPE was found to be seriously dependent on its aggregation property in aqueous solution with efficiency of 34 %, which is 6 times higher than pure ATPP. The versatility of this molecular structure modulation strategy along with the ACQ‐to‐AIE transformation in this work provides direction to guide for applying liposoluble porphyrins in aqueous phase by designs of synthetic porphyrin AIEgens. [ABSTRACT FROM AUTHOR]

Surface recombination at the photoanode/electrolyte junction seriously impedes photoelectrochemical (PEC) performance. Through coating of photoanodes with oxygen evolution catalysts, the photocurrent can be enhanced; however, current systems for water splitting still suffer from high recombination. We describe herein a novel charge transfer system designed with BiVO4 as a prototype. In this system, porphyrins act as an interfacial‐charge‐transfer mediator, like a volleyball setter, to efficiently suppress surface recombination through higher hole‐transfer kinetics rather than as a traditional photosensitizer. Furthermore, we found that the introduction of a "setter" can ensure a long lifetime of charge carriers at the photoanode/electrolyte interface. This simple interface charge‐modulation system exhibits increased photocurrent density from 0.68 to 4.75 mA cm−2 and provides a promising design strategy for efficient photogenerated charge separation to improve PEC performance. [ABSTRACT FROM AUTHOR]

Highly efficient detection in the aqueous phase for water‐insoluble organic molecule probes is challenging. The bright aggregated‐state electrochemiluminescence (ECL) of 1,1‐disubstituted 2,3,4,5‐tetraphenylsiloles by a co‐reactant approach was discovered, and a heterogeneous aggregation‐induced emission ECL (HAIE‐ECL) was constructed at the electrode surface, showing very high ECL efficiency (37.8 %) and selective recognition for industrially important DNBP plasticizer with a low detection limit of 0.15 nm in the water phase. A mechanistic study indicates that ECL is mainly generated due to the high electron affinity of siloles and restriction of the intramolecular motions caused by their propeller‐like noncoplanar structures. This system realizes the sensing of organic‐based ECL in the water phase by solving the crucial problems of water insolubility and aggregation‐caused quenching (ACQ), and demonstrates potential for further application because of its design and high efficiency. A heterogeneous aggregation‐induced emission electrochemiluminescence (HAIE‐ECL) system with high ECL efficiency has been developed according to the AIE strategy. This system can detect a widely used plasticizer, DNBP, in the aqueous phase, and solve water insolubility and aggregation‐caused quenching (ACQ) in small organic molecule probe systems. [ABSTRACT FROM AUTHOR]