Promotional effects of In(PO3)3 on the high catalytic activity of CuO-In(PO3)3/C for the CO2 reduction reaction.

The construction of Cu-In bi-component catalysts is an effective strategy to enhance the electrocatalytic properties towards the CO2 reduction reaction (CO2RR). However, realizing the co-promotion of In and heteroatom P on the electrocatalytic performance is still a challenge due to the poor selectivity of metal phosphides. Herein, a novel bi-component catalyst (CuO-In(PO3)3/C) was successfully synthesized via a facile one-pot reaction to realize the integration of Cu, In, and P species for the enhancement of electrocatalysis. In particular, the as-obtained nanorod-like Cu-In(PO3)3/C exhibits superior electrocatalysis towards the CO2RR, with the highest Faraday efficiency of CO (FECO) of 88.5% at -0.586 V. Furthermore, Cu-In(PO3)3/C shows better activity, selectivity, and stability in the CO2RR; in particular, the total current density can reach 178.09 mA cm-2 at -0.886 V in 2.0 M KOH solution when a flow cell is employed. This work provides a reliable method for simplifying the synthesis of novel Cu-based catalysts and exploits the application of heteroatom P in the field of efficient CO2RR.

Adjustable luminescence copper nanoclusters nanoswitch based on competitive coordination of samarium ions for cascade detection of adenosine triphosphate and acid phosphatase activity.

Benefit from the strong coordination property, lanthanide metal ions have been used as competitive reagents to modulate the fluorescence changes of the system. However, lanthanide metal ions as inducers for aggregation-induced emission enhancement in nanosystems is rare. Herein, we report a "turn on-off-on" fluorescent switch for cascade detection of acid phosphatase (ACP) and adenosine triphosphate (ATP) based on the competitive coordination of samarium ions (Sm3+). Novel copper nanoclusters (CuNCs) with long wavelength emission (614 nm) stabilized by glutathione (GSH) and glycylglycine (Gly-Gly) have been confirmed to have AIE property. With the continuous aggregation of GSH/Gly-Gly CuNCs under the induction of Sm3+, the fluorescence of the system increased to achieve the "turn-on" process. The coordinated behaviour between Sm3+ and GSH/Gly-Gly CuNCs is discussed. Due to the strong metal coordination ability of ATP, the Sm3+ coordinated with the GSH/Gly-Gly CuNCs is competed out, resulting in the fluorescence "turn-off" process of the system. As the substrate of enzymatic hydrolysis of ACP, with the continuous hydrolysis of ATP by ACP, Sm3+ coordinates with GSH/Gly-Gly CuNCs again, which leads to the AIE effect and realize the fluorescence "turn-on" process of the system. This strategy results in ATP linear range of 0.508 ~ 120.0 µM with a detection limit of 0.508 µM (S/N = 3) and ACP linear range of 0.011 ~ 30.0 U·L-1 with a detection limit of 0.011 U·L-1 (S/N = 3). Application to biologic samples was successful.

Elaborate tree-like Cu-Ag clusters from green electrodeposition for efficiently electrocatalyzing CO2 conversion into syngas.

The electrocatalytic carbon dioxide reduction (CO2RR) is one of the emerging technologies that can effectively transform carbon dioxide (CO2) into valuable products. Electrocatalysts deriving from green synthesis methods will significantly help to establish a new green carbon cycle. Herein, a green electrodeposition method without additional reducing agents was used to synthesize Cu-Ag bimetallic catalysts, and it is shown that the combination of Cu and Ag obviously affects the morphology of the Cu-Ag catalysts, resulting in the formation of elaborate tree-like Cu-Ag clusters. An as-deposited Cu-Ag/carbon fiber (Cu-Ag/CF) catalyst exhibits high activity, selectivity and stability toward the CO2RR; in particular, the elaborate dendritic Cu-Ag/CF can efficiently reduce CO2 to syngas with high selectivity (Faradaic efficiency (FE) > 95%) at a low onset potential (-0.5 V). This work provides a rational strategy to overcome the significantly different reaction capacities during the reduction of Ag+ and Cu2+, leading to the formation of a controlled morphology of Cu-Ag, which is favourable for the design and development of highly efficient Cu or Ag catalysts via green methods for electrocatalyzing the CO2RR.

Synthesis of a carbon-wrapped microsphere MoO2/Mo2C heterojunction as an efficient electrocatalyst for the oxygen reduction reaction and the hydrogen evolution reaction.

The development of non-noble metal catalysts for the optimization of conversion and storage devices is an important research topic. Hence, the microsphere MoO2/Mo2C/C heterojunction composites, which play an important role in the oxygen reduction reaction (ORR) and the hydrogen evolution reaction (HER), were synthesized using the solvothermal-sintering method. The results revealed that the as-prepared composite exhibited better ORR and HER catalytic performances than those of MoO2/Mo2C and Vulcan XC-72R (carbon black), and approaching that of commercial Pt/C. At the same time, it has a superior methanol tolerance and electrochemical stability than that of the commercial Pt/C. The excellent performance may be attributed to the synergistic effect of the MoO2/Mo2C heterostructure, highly conductive Vulcan XC-72R, and oxygen vacancies (Ov). This research offers new insights into the design and synthesis of cost-effective, environmentally friendly heterojunction composite catalysts used as a high-performance cathode material in fuel cells and water splitting.

Mo2C promoted electrocatalysis of the Pt/Mo2C (C) heterostructure for a superior hydrogen evolution reaction.

Constructing a unique electrochemical interface to enhance the catalytic capacity of Pt-based catalysts is indispensable for wider application of the hydrogen evolution reaction (HER). Herein, platinum-analogous molybdenum carbide (Mo2C) was combined with a lower content of Pt to construct the Pt/Mo2C (C) heterostructure via a solid-phase method, using ammonium molybdate as the precursor. Vulcan-C served as a support to promote the distribution of the Pt and Mo2C heterostructure, and cooperative effects between Pt and the Mo2C heterostructure contributed to the significantly improved catalytic capacity of Pt. The obtained Pt/Mo2C (C) exhibits superior HER activity and enhanced long-term durability in the acidic medium, with a low overpotential of 38 mV at 10 mA cm-2 and a low Tafel slope of 24 mV dec-1. In particular, a drastically enhanced amount of H2 production can be achieved (6837.28 mmol h-1 g-1). This facile approach not only provides a new pathway for constructing novel heterostructures but also gives an insight into the design of cost-effective Pt-based materials for an efficient HER.

A space-sacrificed pyrolysis strategy for boron-doped carbon spheres with high supercapacitor performance.

Targeting the potential application of morphological carbon in electrode materials, a space-sacrificed pyrolysis strategy was applied for the preparation of boron-doped carbon spheres (B-CSs), using commercial triphenyl borate (TPB) as carbon and boron co-source. The unique structure of TPB play an important role in the sacrificed space, and has notable effect on the surface area of B-CSs. The as prepared B-CSs possess a high surface area and boron content with uniform boron atoms distribution and high surface polarity, which contributes to the improvement of pseudo-capacitance. The sizes, specific surface areas, and boron contents of B-CSs can be easily regulated by varying the experimental parameters. The optimal sample has a boron content of 1.38 at%, surface area of 560 m2 g-1 and specific capacitance of 235F g-1. We can believe that this work would provide a flexible and extensible preparation technique of B-CSs for electrochemical applications.

Three 3D Co(ii) cluster-based MOFs constructed from polycarboxylate acids and bis(imidazole) ligands and their derivatives: magnetic properties and catalytic performance for the ORR.

Three 3D polymeric complexes containing polynuclear Co(ii) units, [Co3(bpda)3(bib)2]·H2O (1), [Co5(OH)2(H2O)2(bpda)4(bib)2]·2H2O (2), and [Co2(OH)(bib)(bpt)]·H2O (3) (H2bpda = biphenyl-2,4'-dicarboxylic acid, H3bpt = biphenyl-3,4',5-tricarboxylic acid, bib = 1,4-bis(1-imidazolyl)benzene), have been prepared by urothermal synthesis. Complex 1 exhibits an unusual (4,6)-connected 3D network based on binuclear Co(ii) clusters and Co2+ centers bridged by bpda2- and bib ligands. Complex 2, containing a novel pentanuclear Co(ii) cluster, features a porous 3D MOF with a regular nanosized tunnel. Complex 3 contains an interesting tetranuclear Co(ii) cluster and displays an amazing 3D porous MOF built from double-layered 2D [Co2(µ3-OH)(bpt)3]n networks pillared by two rows of bib spacers. In the title complexes, polycarboxylate acids serve to construct and stabilize the polynuclear Co(ii) clusters, while bis(imidazole)s help to expand the dimensionality of MOFs. Complexes 2 and 3 show antiferromagnetic properties. Compound 3 with high surface area, high yield, high purity, and high chemical stability was used as a precursor to fabricate Co,N-codoped porous carbon materials by simple carbonization under an Ar atmosphere. The catalytic properties of the Co,N-codoped porous carbon material derived from complex 3 (denoted as CoNC-3) as an ORR electrocatalyst were studied. CoNC-3 displays superior electrocatalytic performances for the ORR.

Highly sensitive aptamer based on electrochemiluminescence biosensor for label-free detection of bisphenol A.

Bisphenol A (BPA), a typical endocrine disruptor, is widely used as a key monomer in the packaging industry. Residual monomer can transfer from the package material to the food and thereby pose a risk to the health of the consumer, so determination of BPA migration is highly important for food safety control. In this study, a simple but sensitive electrochemiluminescence (ECL) biosensor, which combines the characteristics of high selectivity of an aptamer and high sensitivity of ECL, has been developed to detect BPA from package materials. The aptamer was immobilized on a gold electrode surface through Au-S interaction. The aptamer was then hybridized with complementary DNA (CDNA) to form double-stranded DNA (dsDNA). Ru(phen)32+ can intercalate into the grooves of dsDNA and acts as an ECL indicator; high ECL intensity can therefore be detected from the electrode surface. In the presence of BPA, which can competitively bind with the aptamer owing to their high affinity, Ru(phen)32+ is released from the electrode surface and the ECL of the system is decreased. The decreasing ECL signal has a linear relationship with BPA in the range of 0.1-100 pM with a detection limit of 0.076 pM. The developed biosensor has been applied to detect migration of BPA from different categories of canned drink with satisfactory results.

In situ electro-deposition of Pt micro-nano clusters on the surface of {[PMo12O40]3-/PAMAM}n multilayer composite films and their electrocatalytic activities regarding methanol oxidation.

The {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films are prepared by LBL electrostatic assembly technique, and their uniform and homogeneous traits have been verified by cyclic voltammetry. The {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films with PAMAM as the outmost layer, having an open structure and exhibiting good penetrability for the solvent molecules at low pH, are used as matrices for electro-deposition of Pt micro-nano clusters in situ. X-ray photoelectron spectroscopy (XPS) analysis and field emission scanning electron microscope (FE-SEM) characterization show that the unique Pt micro-nano clusters with flower-like structure have been immobilized on the surface of {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films. The morphologies of Pt micro-nano clusters are influenced by electro-deposition conditions such as deposition potential, deposition time, and the number of layers of {[PMo(12)O(40)](3-)/PAMAM}(n) multilayer films. Pt(-clusters)-{PMo(12)/PAMAM}(3) composite films demonstrate good electrocatalytic activities regarding methanol oxidation and improved tolerance of CO.