Jason

Endowing materials with specific functions which are not readily available yet, is always of great importance but extremely challenging. Co4N with beneficial metallic characteristics has been proved highly active for water oxidation, while it is notoriously poor for hydrogen evolution reaction (HER) catalysis, due to its unfavourable d band energy level. Herein, we successfully endow Co4N with prominent HER catalytic capability, by tailoring the d band centers via transition metal doping. The V doped Co4N nanosheets display an overpotential of 37 mV at 10 mA cm-2, which is substantially better than Co4N and even close to the benchmark Pt/C catalyst. XANES, UPS and DFT calculation consistently reveal the enhanced performance is attributed to the downshift of d band centers, which facilitates the H desorption. The concept can offer valuable insights into the design of catalysts for HER and beyond.

The [4+2] and [3+2] annulations of α-chloroaldehydes with dithioesters are reported. In the presence of an N-heterocyclic carbene (NHC) catalyst, the [4+2] annulation went smoothly to afford highly substituted 1,4-oxathiin-2(3H)-ones, while the [3+2] annulation was observed to give 1,3-oxathioles in the absence of an NHC.