MoS 2 -based transition-metal chalcogenides are considered as cost-effective, highly active, and stable materials with great potential in the application of electrocatalytic hydrogen production. However, their limited quantity of active sites and poor conductivity have hampered the efficiency of hydrogen production. Combining calculations and experiments, we demonstrate that P dopants could be the new active sites in the basal plane of MoS 2 and help improve the intrinsic electronic conductivity, leading to a significantly improved activity for hydrogen evolution. Furthermore, the P-doped MoS 2 nanosheets show enlarged interlayer spacing, facilitating hydrogen adsorption and release progress. Experimental results indicate that the P-doped MoS 2 nanosheets with enlarged interlayer spacing exhibit remarkable electrocatalytic activity and good long-term operational stability (with Tafel slope of 34 mV/dec and an extremely low overpotential of ∼43 mV at 10 mA/cm 2 ) . Our method demonstrated a facile technology for improving the electrocatalytic efficiency of MoS 2 for hydrogen evolution reaction through nonmetal doping, which could be explored to enhance and understand the catalytic properties of other transition-metal chalcogenides.

Herein, the authors explicitly reveal the dual‐functions of N dopants in molybdenum disulfide (MoS2) catalyst through a combined experimental and first‐principles approach. The authors achieve an economical, ecofriendly, and most efficient MoS2‐based hydrogen evolution reaction (HER) catalyst of N‐doped MoS2 nanosheets, exhibiting an onset overpotential of 35 mV, an overpotential of 121 mV at 100 mA cm−2 and a Tafel slope of 41 mV dec−1. The dual‐functions of N dopants are (1) activating the HER catalytic activity of MoS2 S‐edge and (2) enhancing the conductivity of MoS2 basal plane to promote rapid charge transfer. Comprehensive electrochemical measurements prove that both the amount of active HER sites and the conductivity of N‐doped MoS2 increase as a result of doping N. Systematic first‐principles calculations identify the active HER sites in N‐doped MoS2 edges and also illustrate the conducting charges spreading over N‐doped basal plane induced by strong Mo 3d–S 2p–N 2p hybridizations at Fermi level. The experimental and theoretical research on the efficient HER catalysis of N‐doped MoS2 nanosheets possesses great potential for future sustainable hydrogen production via water electrolysis and will stimulate further development on nonmetal‐doped MoS2 systems to bring about novel high‐performance HER catalysts.

Within the framework of the full potential projector-augmented wave methodology, we present a promising low-scaling GW implementation. It allows for quasiparticle calculations with a scaling that is cubic in the system size and linear in the number of k points used to sample the Brillouin zone. This is achieved by calculating the polarizability and self-energy in real space and imaginary time. The transformation from the imaginary time to the frequency domain is done by an efficient discrete Fourier transformation with only a few nonuniform grid points. Fast Fourier transformations are used to go from real space to reciprocal space and vice versa. The analytic continuation from the imaginary to the real frequency axis is performed by exploiting Thiele's reciprocal difference approach. Finally, the method is applied successfully to predict the quasiparticle energies and spectral functions of typical semiconductors (Si, GaAs, SiC, and ZnO), insulators (C, BN, MgO, and LiF), and metals (Cu and SrVO 3 ). The results are compared with conventional GW calculations. Good agreement is achieved, highlighting the strength of the present method.

In a recent work, van Setten and co-workers have presented a carefully converged GW study of 100 closed shell molecules [ J. Chem. Theory Comput. 2015 , 11 , 5665 - 5687 ]. For two different codes they found excellent agreement to within a few 10 meV if identical Gaussian basis sets were used. We inspect the same set of molecules using the projector augmented wave method and the Vienna ab initio simulation package (VASP). For the ionization potential, the basis set extrapolated plane wave results agree very well with the Gaussian basis sets, often reaching better than 50 meV agreement. In order to achieve this agreement, we correct for finite basis set errors as well as errors introduced by periodically repeated images. For positive electron affinities differences between Gaussian basis sets and VASP are slightly larger. We attribute this to larger basis set extrapolation errors for the Gaussian basis sets. For quasi particle (QP) resonances above the vacuum level, differences between VASP and Gaussian basis sets are, however, found to be substantial. This is tentatively explained by insufficient basis set convergence of the Gaussian type orbital calculations as exemplified for selected test cases.