Defect engineering is an effective strategy to improve the activity of two-dimensional molybdenum disulfide base planes toward electrocatalytic hydrogen evolution reaction. Here, we report a Frenkel-defected monolayer MoS2 catalyst, in which a fraction of Mo atoms in MoS2 spontaneously leave their places in the lattice, creating vacancies and becoming interstitials by lodging in nearby locations. Unique charge distributions are introduced in the MoS2 surface planes, and those interstitial Mo atoms are more conducive to H adsorption, thus greatly promoting the HER activity of monolayer MoS2 base planes. At the current density of 10 mA cm-2, the optimal Frenkel-defected monolayer MoS2 exhibits a lower overpotential (164 mV) than either pristine monolayer MoS2 surface plane (358 mV) or Pt-single-atom doped MoS2 (211 mV). This work provides insights into the structure-property relationship of point-defected MoS2 and highlights the advantages of Frenkel defects in tuning the catalytic performance of MoS2 materials. 

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Frenkel-defected monolayer MoS2 catalysts for efficient hydrogen evolution

Hydrazine hydrate-assisted adjustment of sulfur-rich MoS2 as hydrogen evolution electrocatalyst

Facile formation of Mo-vacancy defective MoS2/CdS nanoparticles enhanced efficient hydrogen production

Graphitic carbon nitride (g-C3N4) has been paid increasingly attentions in U(VI) removal due to the visible-light response, whereas the high recombination of photogenerated electron and holes limited the actual environmental application. Herein, Z-scheme MoS2/g-C3N4 heterojunction was fabricated to enhance removal of U(VI) from aqueous solution. The microscopic and spectroscopic characterizations showed that addition of MoS2 on surface of g-C3N4 increased separation efficiency of photogenerated charge, decreased the bandgap and improved the intensity of light adsorption. Approximate 82% of UO22+ was photo-reduced by MoS2/g-C3N4 after 1 h of light irradiation at pH 4.5. The high effective photocatalytic reduction of U(VI) on MoS2/g-C3N4 was attributed to ·O2− radials according to quenching experiments. XPS analysis showed that the adsorbed U(VI) was photo-reduced into U(IV). These findings are crucial for the design of C3N4-based composites with high efficient photocatalytic performance and exclusive selectivity into actual environmental cleanup.

Jing Huang

Papers

Synthesis and photocatalytic hydrogen activity of Mo1−xS2 nanosheets with controllable Mo vacancies