To construct photocatalytically active MOFs, various strategies have recently been developed. We have synthesized and characterized a new metal-organic framework (MOF-253-Pt) material through immobilizing a platinum complex in 2,2 0 -bipyridine-based microporous MOF (MOF-253) using a post-synthesis modification strategy.The functionalized MOF-253-Pt serves both as a photosensitizer and a photocatalyst for hydrogen evolution under visible-light irradiation. The photocatalytic activity of MOF-253-Pt is approximately five times higher than that of the corresponding complex. The presence of the short Pt/Pt interactions in the framework was revealed with extended X-ray absorption fine structure (EXAFS) spectroscopy and low temperature luminescence. These interactions play an important role in improving the photocatalytic activity of the resulting MOF.

The single-site catalyst (SSC) characteristic of atomically dispersed active centers will not only maximize the catalytic activity,but also provideapromising platform for establishing the structure-activity relationship.H owever,a rbitrary arrangements of active sites in the existed SSCs make it difficult for mechanism understanding and performance optimization. Now, aw ell-defined ultrathin SSC is fabricated by assembly of metal-porphyrin molecules,w hiche nables the precise identification of the active sites for d-orbital energy engineering.The activity of as-assembled products for electrocatalytic CO 2 reduction is significantly promoted via lifting up the energy level of metal d z 2 orbitals,e xhibiting ar emarkable Faradaic efficiency of 96 %a tt he overpotential of 500 mV. Furthermore,aturnover frequency of 4.21 s À1 is achieved with negligible decayo ver4 8h.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.Figure 5. DFT calculation of electrocatalytic CO 2 reduction on STPyP-Co.A)Calculated free-energys tates of CO 2 reduction to CO on STPyP-Co and MTPyP-Co. B) Optimized geometry of intermediate [STPyP-Co-COOH].C ),D) Spatial representationo fHOMO orbital of [STPyP-Co-COOH] and [MTPyP-Co-COOH] intermediates, respectively.

Graphitic C3N4 (g-C3N4) has continuously attracted attentions since it was reported as a metal free semiconductor for water splitting. However, its ability for evolving hydrogen from water is significantly dependent on the use of noble metal co-catalyst, mainly Pt. In recent years, a good progress has been achieved in developing cocatalysts containing earth abundant elements only for constructing low cost and efficient g-C3N4 based photocatalytic systems. Besides, exfoliation of bulk g-C3N4 into two dimensional g-C3N4 nanosheets offers large surface area and exposed active sites, which are beneficial for activity enhancement. Furthermore, oxygen evolution and CO2 photoreduction over g-C3N4 have caught increasing interests due to the demand to achieve overall water splitting and conversion of CO2 into chemicals and fuels. In this mini-review, we will briefly summarize the latest research works on g-C3N4 based photocatalytic systems during the last three years with emphasis on the progress achieved in enhancing hydrogen evolution activity of g-C3N4 by loading noble metal free co-catalysts, exfoliating bulk g-C3N4 into nanosheets, and the application of g-C3N4 system in photocatalytic O2 evolution and CO2 reduction.

MiRNAs are an emerging type of biomarker for diagnostics and prognostics. A reliable sensing strategy that can monitor miRNA expression in living cancer cells would be critical in view of its extensive advantages for fundamental research related to miRNA-associated bioprocesses and biomedical applications. Conventional miRNA sensing methods include northern blot, microarrays and real-time quantitative PCR. However, none of them is able to monitor miRNA levels expressed in living cancer cells in a real-time fashion. Some fluorescennt biosensors developed recently from carbon nanomaterials, such as single-walled carbon nanotubes (SWNTs), graphene oxide (GO), and carbon nanoparticles, have been successfully used for assaying miRNA in vitro; however the preparation processes are often expensive, complicated and time-consuming, which have motivated the research on other substitute and novel materials. Herein we present a novel sensing strategy based on peptide nucleic acid (PNA) probes labeled with fluorophores and conjugated with an NMOF vehicle to monitor multiplexed miRNAs in living cancer cells. The NMOF works as a fluorescence quencher of the labelled PNA that is firmly bound with the metal center. In the presence of a target miRNA, PNA is hybridized and released from the NMOF leading to the recovery of fluorescence. This miRNA sensor not only enables the quantitative and highly specific detection of multiplexed miRNAs in living cancer cells, but it also allows the precise and in situ monitoring of the spatiotemporal changes of miRNA expression.