The Z‐scheme process is a photoinduced electron‐transfer pathway in natural oxygenic photosynthesis involving electron transport from photosystem II (PSII) to photosystem I (PSI). Inspired by the interesting Z‐scheme process, herein a photocatalytic hydrogen evolution reaction (HER) employing chlorophyll (Chl) derivatives, Chl‐1 and Chl‐2, on the surface of Ti3C2Tx MXene with two‐dimensional accordion‐like morphology, forming Chl‐1@Chl‐2@Ti3C2Tx composite, is demonstrated. Due to the frontier molecular orbital energy alignments of Chl‐1 and Chl‐2, sublayer Chl‐1 is a simulation of PSI, whereas upper layer Chl‐2 is equivalent to PSII, and the resultant electron transport can take place from Chl‐2 to Chl‐1. Under the illumination of visible light (>420 nm), the HER performance of Chl‐1@Chl‐2@Ti3C2Tx photocatalyst was found to be as high as 143 μmol h−1 gcat−1, which was substantially higher than that of photocatalysts of either Chl‐1@Ti3C2Tx (20 μmol h−1 g−1) or Chl‐2@Ti3C2Tx (15 μmol h−1 g−1).

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The cerebrospinal fluid-contacting nucleus (CSF-CN) may influence actual composition of the CSF for non-synaptic signal transmission via releasing or absorbing bioactive substances, which distributes and localizes in the ventral periaqueductal central gray of the brainstem. Previous studies demonstrated that CSF-CN was involved in neuropathic pain and morphine dependence. Thus, to identify whether extracellular signal-regulated kinase 5 (ERK5) distributed in the CSF-CN and its function on the formation and development of morphine physical dependence, morphine withdrawal-like behavioral test and immunofluorescent technique were used in this research. Morphine was subcutaneously injected by an intermittent and escalating procedure to induce physical dependence, which was measured by withdrawal symptoms. In this study, we found that horseradish peroxidase-conjugated toxin subunit B/p-ERK5 double-labeled neurons expressed in the CSF-CN of normal rats. ERK5 signaling pathway was remarkably activated by naloxone-precipitated withdrawal in the CSF-CN. Moreover, selective attenuation of p-ERK5 expression in the CSF-CN by lateral ventricle injection of BIX02188 could significantly relieve morphine withdrawal symptom. These findings confirmed that the activation of p-ERK5 in the CSF-CN might contribute to morphine physical dependence.

Hydrogen energy is an abundant, clean, sustainable and environmentally friendly renewable energy source. Therefore, the production of hydrogen by photocatalytically splitting water on semiconductors has been considered in recent years as a promising and sustainable strategy for converting solar energy into chemical energy to replace conventional energy sources and to solve the growing problem of environmental pollution and the global energy crisis. However, highly efficient solar-driven photocatalytic hydrogen production remains a huge challenge due to the poor visible light response of available photocatalytic materials and the low efficiency of separation and transfer of photogenerated electron-hole pairs. In the present work, organic heterojunction structures based on bacteriochlorophyll (BChl) and chlorophyll (Chl) molecules were introduced and used for solar-driven photocatalytic hydrogen production from water under visible light. Also, noble metal-free photocatalyst was successfully constructed on Ti 3 C 2 T x nanosheets by simple successive deposition of Chl and BChl, which was used for the photocatalytic splitting water to hydrogen evolution reaction (HER). The results show that the optimal BChl@Chl@Ti 3 C 2 T x composite has a high HER performance with 114 μmol/h/g cat , which is much higher than the BChl@Ti 3 C 2 T x and Chl@Ti 3 C 2 T x composites.