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Electrocatalytic reduction of CO2 is one of the most attractive approaches for converting CO2 into valuable chemical feedstocks and fuels. This work reports a catalyst comprising graphdiyne-decorated bismuth subcarbonate (denoted as BOC@GDY) for efficient electroreduction of CO2 to formate. The BOC@GDY shows a stable current density of 200 mA cm−2 at –1.1 V in a flow cell configuration, with a faradaic efficiency of 93.5% for formate. Experimental results show that the synergistic effect in BOC@GDY is beneficial for the CO2 adsorption affinity, the reaction kinetics and the selectivity for formate. In addition, in-situ X-ray absorption and Raman spectroscopy indicate that the electron-rich GDY could facilitate the reduction from Bi(III) to Bi(0), thus leading to more active sites. We also demonstrate that the promoting effect of GDY in CO2 electroreduction can be further extended to other metal catalysts. To the best of our knowledge, such general promoting functions of GDY for CO2 electroreduction have not been documented thus far.

Developing highly active catalysts for photo/electrocatalytic water splitting is an attractive strategy to produce H2 as a renewable energy source. In this study, a new nickel boron oxide/graphdiyne (NiBi/GDY) hybrid catalyst was prepared by a facile synthetic approach. Benefitting from the strong electron donating ability of graphdiyne, NiBi/GDY showed an optimized electronic structure containing lower valence nickel atoms and demonstrated improved catalytic performance. As expected, NiBi/GDY displayed a high photocatalytic H2 evolution rate of 4.54 mmol g−1 h−1, 2.9 and 4.5 times higher than those of NiBi/graphene and NiBi, respectively. NiBi/GDY also displayed outstanding electrocatalytic H2 evolution activity in 1.0 M KOH solution, with a current density of 400 mA/cm2 at an overpotential of 478.0 mV, which is lower than that of commercial Pt/C (505.3 mV@400 mA/cm2). This work demonstrates that GDY is an ideal support for the development of highly active catalysts for photo/electrocatalytic H2 evolution.

This study prepared iron-manganese oxide-modified biochar (FM-BC) by impregnating rice straw biochar (BC) with a mixed solution of ferric nitrate and potassium permanganate. The effects of pH, FM-BC dosage, interference of coexisting ions, adsorption time, incipient Pb(II) concentration, and temperature on the adsorption of Pb(II) by FM-BC were investigated. Moreover, the Pb(II) adsorption mechanism of FM-BC was analyzed using a series of characterization techniques. The results showed that the Fe-Mn oxide composite modification significantly promoted the physical and chemical functions of the biochar surface and the adsorption capacity of Pb(II). The specific surface area of FM-BC was 18.20 times larger than that of BC, and the maximum Pb(II) adsorption capacity reached 165.88 mg/g. Adsorption kinetic tests showed that the adsorption of Pb(II) by FM-BC was based on the pseudo-second-order kinetic model, which indicated that the adsorption process was mainly governed by chemical adsorption. The isothermal adsorption of Pb(II) by FM-BC conformed to the Langmuir model, indicating that the adsorption process was spontaneous and endothermic. Characterization analyses (Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy) showed that the adsorption mechanism of Pb(II) by FM-BC was mainly via electrostatic adsorption, chemical precipitation, complexation, ion exchange, and the transformation of Mn2O3 into MnO2. Therefore, FM-BC is a promising adsorbent for Pb(II) removal from wastewater.

Fe-Mn oxide-modified biochar (BC-FM) was used to remediate Cd-contaminated soil and mitigate Cd accumulation in rice. The roles of Fe and Mn in soil Cd immobilization and in controlling Cd uptake by rice were investigated via X-ray photoelectron spectroscopy (XPS) characterization and chemical analysis. Fe and Mn loaded on BC-FM increased the removal efficiencies of CaCl

The development of efficient heterogeneous catalysts for alkyne hydrogenation with high activity and selectivity is highly desirable and yet remains a great challenge. Herein, a Pd single-atom catalyst (Pds–GDY) is prepared using graphdiyne as support, and used in the semihydrogenation of alkynes. As a proof of concept, the Pds–GDY exhibits a high activity for the semihydrogenation of phenylacetylene under mild reaction conditions, with a TOF of 6290 h−1, and a selectivity of 99.3% at 100% conversion, both much higher than those of the counterparts comprising Pd nanoparticles (NPs), namely, PdNP1–GDY (with 2 nm Pd NPs) and PdNP2–GDY (with 12 nm Pd NPs). In addition, after the full conversion of phenylacetylene, Pds–GDY could still maintain a selectivity as high as 98.9% towards styrene, with almost no phenylethane produced even with a prolonged reaction time; in contrast, for PdNP1–GDY and PdNP2–GDY, within the same reaction time, the selectivity decreases dramatically to 66.6% and 8.5%, respectively. Infrared spectroscopy reveals that Pds–GDY features the weakest adsorption to styrene, which is responsible for its high performance. This work provides an effective strategy to rationally design Pd catalysts for semihydrogenation of alkynes to alkenes with desirable activity and selectivity.

Metal-halide perovskite nanocrystals have emerged as one of the promising photocatalysts in the photocatalysis field owing to their low-cost and excellent optoelectronic properties. However, this type of nanocrystals generally displays low activity in photocatalytic CO2 reduction owing to the lack of intrinsic catalytic sites and insufficient charge separation. Herein, we functionalized CsPbBr3 nanocrystals with graphitic carbon nitride, containing titanium-oxide species (TiO-CN) to develop an efficient composite catalyst system for photocatalytic CO2 reduction using water as the electron source. Compared to its congener with pristine CsPbBr3, the introduction of TiO-CN could not only increase the number of active sites, but also led to a swift interfacial charge separation between CsPbBr3 and TiO-CN due to their favorable energy-offsets and strong chemical bonding behaviors, which endowed this composite system with an obviously enhanced photocatalytic activity in the reduction of CO2 to CO with water as the sacrificial reductant. Over 3-fold and 6-fold higher activities than those of pristine CsPbBr3 nanocrystals and TiO-CN nanosheets, respectively, were observed under visible light irradiation. Our study provides an effective strategy for improving the photocatalytic activity of metal-halide perovskite nanocrystals, thus promoting their photocatalytic application in the field of artificial photosynthesis.

Metal oxide-modified biochar showed excellent adsorption performance in wastewater treatment. Iron nitrate and potassium permanganate were oxidative modifiers through which oxygen-containing groups and iron-manganese oxides could be introduced into biochar. In this study, iron-manganese (Fe-Mn) oxide-modified biochar (BC-FM) was synthesized using rice straw biochar, and the adsorption process, removal effect, and the mechanism of cadmium (Cd) adsorption on BC-FM in wastewater treatment were explored through batch adsorption experiments and characterization (SEM, BET, FTIR, XRD, and XPS). Adsorption kinetics showed that the maximum adsorption capacity of BC-FM for Cd(II) was 120.77 mg/g at 298 K, which was approximately 1.5-10 times the amount of adsorption capacity for Cd(II) by potassium-modified or manganese-modified biochar as mentioned in the literature. The Cd(II) adsorption of BC-FM was well fit by the pseudo-second-order adsorption and Langmuir models, and it was a spontaneous and endothermic process. Adsorption was mainly controlled via a chemical adsorption mechanism. Moreover, BC-FM could maintain a Cd removal rate of approximately 50% even when reused three times. Cd(II) capture by BC-FM was facilitated by coprecipitation, surface complexation, electrostatic attraction, and cation-π interaction. Additionally, the loaded Fe-Mn oxides also played an important role in the removal of Cd(II) by redox reaction and ion exchange in BC-FM. The results suggested that BC-FM could be used as an efficient adsorbent for treating Cd-contaminated wastewater.

A visible-light-response, efficient and robust photo-catalyst for CO2 reduction is highly desirable. Herein, we demonstrate that single titanium-oxide species implanted in two-dimensional (2D) graphitic carbon nitride (g-C3N4) matrix (2D TiO-CN) can efficiently photo-catalyze the reduction of CO2 to CO under the irradiation of visible light. The synergistic interaction between single titanium oxide species and g-C3N4 in 2D TiO-CN not only enhances the separation of photo-excited charges, but also results in visible light response of single titanium-oxide species, realizing high activity of CO2 photo-reduction with extremely high CO generation rate of 283.9 μmol·h−1·g−1, 5.7, 6.8 and 292.2 times larger than those of TiO2/CN hybrid material, CN and commercial TiO2, respectively. Time-resolved fluorescence and electron spin resonance spectroscopy revealed the catalytic mechanism of the fabricated 2D TiO-CN photocatalysts for CO2 reduction.

Two Pt single-atom catalysts (SACs) of Pt-GDY1 and Pt-GDY2 were prepared on graphdiyne (GDY)supports. The isolated Pt atoms are dispersed on GDY through the coordination interactions between Pt atoms and alkynyl C atoms in GDY, with the formation of five-coordinated C1 -Pt-Cl4 species in Pt-GDY1 and four-coordinated C2 -Pt-Cl2 species in Pt-GDY2. Pt-GDY2 shows exceptionally high catalytic activity for the hydrogen evolution reaction (HER), with a mass activity up to 3.3 and 26.9 times more active than Pt-GDY1 and the state-of-the-art commercial Pt/C catalysts, respectively. Pt-GDY2 possesses higher total unoccupied density of states of Pt 5d orbital and close to zero value of Gibbs free energy of the hydrogen adsorption (|ΔGPtH* |) at the Pt active sites, which are responsible for its excellent catalytic performance. This work can help better understand the structure-catalytic activity relationship in Pt SACs.

Since its discovery, the direct imaging and determination of the crystal structure of few-layer graphdiyne has proven difficult because it is too delicate under irradiation by an electron beam. In this work, the crystal structure of a six-layered graphdiyne nanosheet was directly observed by low-voltage transmission electron microscopy (TEM) using low current density. The combined use of high-resolution TEM (HRTEM) simulation, electron energy-loss spectroscopy, and electron diffraction revealed that the as-synthesized nanosheet was crystalline graphdiyne with a thickness of 2.19 nm (corresponding to a thickness of six layers) and showed ABC stacking. Thus, this work provides direct evidence for the existence and crystal structure of few-layer graphdiyne, which is a new type of two-dimensional carbon material complementary to graphene.

Metal-halide perovskite nanocrystals have emerged as one of the promising photocatalysts in the photocatalysis field owing to their low-cost and excellent optoelectronic properties. However, this type of nanocrystals generally displays low activity in photocatalytic CO

Two platinum(II) complexes, [PtCl(Q)(DMSO)] (1) and [PtCl(IQ)(DMSO)] (2), bearing 8-hydroxyquinoline (H-Q) and 5,7-diiodo-8-hydroxyquinoline (H-IQ) as the bioactive ligand, respectively, were synthesized and structurally characterized. By MTT assay, complex 2 bearing the IQ ligand showed significantly higher growth inhibition than complex 1 against all the five typical tumor cell lines in the test, but showed no more cytotoxicity against the normal liver cell line HL-7702, suggesting the much better cytotoxic selectivity of 2 than that of 1. In addition, the HepG2 cell line was found to be the most sensitive towards both complexes. Aiming at the HepG2 cell line, both complexes arrested the cell cycle of HepG2 cells in the S phase, as examined by flow cytometry, in which complex 2 showed higher S-phase arrest than 1. This was supported by the down-regulation of cdc25 A, cyclin B, cyclin A, and CDK2 and the up-regulation of p53, p27 and p21 based on western blot assay. Complex 2 also acted as a more effective telomerase inhibitor than 1 by interacting with telomeric/c-myc G-quadruplexes and triggering cell senescence and cell apoptosis. Furthermore, both complexes caused mitochondrial dysfunction, suggesting a potential mitochondrion-mediated apoptotic pathway induced by each complex. From the platinum uptake assay, complex 2 exhibited obvious priority on the cell uptake effect than 1, which should be undoubtedly correlated with the key roles of the 5- and 7-iodo-substituted groups in the IQ ligand of 2. This may well explain the better cytotoxicity and the more significant antitumor mechanism of 2 throughout the study. This work further demonstrated that rational halogen substitution on selected ligands would be greatly beneficial to achieve more promising metal-based antitumor agents.

A new zinc(II) complex (1) of 5-bromo-8-hydroxyquinoline (HBrQ) was prepared and structurally characterized using IR, ESI-MS, elemental analysis, 1H and 13C NMR, as well as single crystal X-ray diffraction analysis. The DNA binding study on complex 1, which was performed using UV-vis, fluorescence and circular dichroism (CD) spectral analyses, suggested that complex 1 interacts with ct-DNA mainly via an intercalative binding mode. The in vitro cytotoxicity of complex 1, compared with Zn(OAc)2·H2O, HBrQ and cisplatin, was screened against a series of tumor cell lines as well as the normal liver cell line HL-7702 using the MTT assay. Complex 1 showed much higher cytotoxicity than Zn(OAc)2·H2O and HBrQ against most of the tumor cell lines, in which BEL-7404 was the most sensitive tumor cell line towards 1, with an IC50 value of 8.69 ± 0.04 μM. Complex 1 was found to greatly induce cell cycle arrest in the BEL-7404 cells at the G2 phase, and consequently to induce cell apoptosis in a dose-dependent mode, which is suggested by the cell apoptosis analysis via the Hoechst 33258 and AO/EB staining assays. Targeting the mitochondria pathway due to the redox activity of Zn, the apoptotic mechanism in the BEL-7404 cells treated by 1 was investigated using reactive oxygen species (ROS) detection, intracellular calcium concentration measurement and caspase-9/3 activity assay, which showed that the cell apoptosis induced by 1 was closely related to the loss of mitochondrial membrane potential, ROS production and enhancement of intracellular [Ca2+], which trigger caspase-9/3 activation via the mitochondrial dysfunction pathway.

Industrial application of overall water splitting requires developing readily available, highly efficient, and stable oxygen evolution electrocatalysts that can efficiently drive large current density. This study reports a facile and practical method to fabricate a non‐noble metal catalyst by directly growing a Co‐Fe Prussian blue analogue on a 3D porous conductive substrate, which is further phosphorized into a bifunctional Fe‐doped CoP (Fe‐CoP) electrocatalyst. The Fe‐CoP/NF (nickel foam) catalyst shows efficient electrocatalytic activity for oxygen evolution reaction, requiring low overpotentials of 190, 295, and 428 mV to achieve 10, 500, and 1000 mA cm−2 current densities in 1.0 m KOH solution. In addition, the Fe‐CoP/NF can also function as a highly active electrocatalyst for hydrogen evolution reaction with a low overpotential of 78 mV at 10 mA cm−2 current density in alkaline solution. Thus, the Fe‐CoP/NF electrode with meso/macropores can act as both an anode and a cathode to fabricate an electrolyzer for overall water splitting, only requiring a cell voltage of 1.49 V to afford a 10 mA cm−2 current density with remarkable stability. This performance appears to be among the best reported values and is much better than that of the IrO2‐Pt/C‐based electrolyzer.

A new anthracycline derivative, anthracene-9-imidazoline hydrazone (9-AIH), was synthesized and selected as an antitumor ligand to afford a copper(II) complex of 9-AIH, cis-[Cu(II)Cl2(9-AIH)] (1). Complex 1 was structurally characterized by IR, elemental analysis, ESI-MS and single crystal X-ray diffraction analysis. By MTT assay, it was revealed that 1 showed overall a higher in vitro cytotoxicity than 9-AIH towards a panel of human tumour cell lines, with IC50 values from 0.94–3.68 μM, in which the BEL-7404 cell line was the most sensitive to 1. By spectral analyses and gel electrophoresis, the DNA binding affinity of 9-AIH and 1 was determined. 9-AIH was suggested to bind with DNA in an intercalative mode, with a quenching constant of 1.04 × 10(4) M(−1) on the EB–DNA complex. While for 1, both intercalative and covalent binding modes were suggested. By flow cytometry, 1 was found to block the cell cycle of BEL-7404 cells in a dose-dependent mode, in which it induced the G2/M phase arrest at 0.5 μM and induced the S phase arrest at higher concentrations of 1.0 or 2.0 μM. From the cellular morphological observations under different fluorescence probe staining, a dose-dependent manner of 1 to induce cell apoptosis in the late stage was suggested. Comparatively, equivalent apoptotic cells, respectively, in the early and late stages were found when incubated with 2.0 μM of 9-AIH. The mitochondrial membrane potential measured by JC-1 staining and the ROS generation in cells detected using a DCFH-DA probe suggested that the cell apoptosis induced by 1 might undergo the ROS-related mitochondrial pathway. Accordingly, the mutant p53 expression was found to be suppressed and the caspase cascade (caspase-9/3) was consequently activated by 1. This action mechanism for 1 in the BEL-7404 cells was unique and was not found in the presence of 9-AIH under the same conditions, indicating their different antitumor mechanism. Furthermore, the in vivo acute toxicity of 1 tested on mice indicated that 1 should be a high cytotoxic antitumor agent, with the LD50 value in the range of 32–45 mg kg(−1), which is much higher than that of 9-AIH. From the above results, the central Cu(II) of 1 in the coordinated mode with 9-AIH was believed to play a key role in exerting both the high cytotoxicity and the effective antitumor mechanism.