Co3O4/CoMoO4 nanocages with an ultrafine crystallite size and high surface area derived from hollow H3PMo12O40@ZIF-67 hybrids exhibit high-performance for electrocatalytic oxygen evolution.

The exploration of highly efficient non-noble metal electrocatalysts for hydrogen evolution reaction (HER) under alkaline conditions is highly imperative but still remains a great challenge. In this work, the nanohybrid of carbon quantum dots and molybdenum phosphide nanoparticle (CQDs/MoP) has been firstly demonstrated as an efficient alkaline HER electrocatalyst. The CQDs/MoP nanohybrid is readily prepared through a charge-directed self-assembly of CQDs with phosphomolybdic acid (HPMoO) at the molecular level, followed by facile phosphatizing at 700 °C. The introduction of CQDs greatly helps to alleviate the agglomeration and surface oxidation of MoP nanoparticles and ensures each MoP nanoparticle to be electronically addressed, thus significantly enhancing the intrinsic catalytic activity of MoP. The optimized CQDs/MoP exhibits high-efficiency synergistic catalysis toward HER in 1 M KOH electrolyte with a low onset potential of -0.08 V and a small Tafel slope of 56 mV dec as well as high durability with negligible current loss for at least 24 h.

Conversion of carbon dioxide (CO2) into useful chemicals is one of promising approaches to reduce global warming and the energy crisis. It is pivotal to develop heterogeneous catalytic systems containing task-specific active sites for chemical transformation of CO2. Herein, we report a urea-functionalized imidazolium-based ionic polymer (UIIP) for metal-, solvent- and additive-free conversion of CO2 into cyclic carbonates. UIIP was readily obtained through simple urea-forming condensation reaction. The high density of urea groups in the host backbone function as hydrogen bond donors to activate epoxides and CO2, while charge-balanced bromide anions serve as nucleophiles to encounter the epoxides from less sterically hindered carbon atom: they cooperatively facilitate ring opening of the epoxides. UIIP exhibits outstanding catalytic activity, superior recyclability and high stability in the cycloaddition reaction of CO2 under mild conditions. A detailed mechanistic insight into the effects of urea groups on the activation of both CO2 and epoxide has been elucidated by DFT calculations.

The fabrication of nanopore with matched pore size, and the existence of multi interferents make the reproducible detection of small-sized molecules by means of solid-state nanopore still challenging. A useful...