In this communication, we report our finding on the transition of ionic liquid [bmim][PF6] from the liquid state to high-melting-point crystal when confined in multiwalled carbon nanotubes. This novel crystallization behavior is explained by the nanosized effect of carbon nanotubes on the structure of ionic liquid.

As am etal-free nitrogen reduction reaction (NRR) photocatalyst, g-C 3 N 4 is available from as calable synthesis at low cost. Importantly,i tc an be readily functionalizedt o enhance photocatalytic activities.H owever,t he use of g-C 3 N 4based photocatalysts for the NRR has been questioned because of the elusive mechanism and the involvement of Nd efects. This work reports the synthesis of ag -C 3 N 4 photocatalyst modified with cyano groups and intercalated K + (mCNN), possessing extended visible-light harvesting capacity and superior photocatalytic NRR activity (NH 3 yield: 3.42 mmol g À1 h À1 ). Experimental and theoretical studies suggest that the -C Ni nm CNN can be regenerated through ap athway analogous to Mars van Krevelen process with the aid of the intercalated K + .T he results confirm that the regeneration of the cyano group not only enhances photocatalytic activity and sustains the catalytic cycle,b ut also stabilizes the photocatalyst.

The layer-structured MoS is a typical hydrogen evolution reaction (HER) electrocatalyst but it possesses poor activity for the oxygen evolution reaction (OER). In this work, a cobalt covalent doping approach capable of inducing HER and OER bifunctionality into MoS for efficient overall water splitting is reported. The results demonstrate that covalently doping cobalt into MoS can lead to dramatically enhanced HER activity while simultaneously inducing remarkable OER activity. The catalyst with optimal cobalt doping density can readily achieve HER and OER onset potentials of -0.02 and 1.45 V (vs reversible hydrogen electrode (RHE)) in 1.0 m KOH. Importantly, it can deliver high current densities of 10, 100, and 200 mA cm at low HER and OER overpotentials of 48, 132, 165 mV and 260, 350, 390 mV, respectively. The reported catalyst activation approach can be adapted for bifunctionalization of other transition metal dichalcogenides.