Transition metal chalcogenides are a promising and extremely pivotal class of electrocatalysts with potential applications in alkaline hydrogen evolution reaction (HER), especially, molybdenum diselenide. Although the exposed edge sites are generally considered to be the active sites of MoSe₂ for HER, an intrinsic behavior (surface species evolution, structure/morphology conversion, stability) of MoSe₂ electrode itself was not unveiled. Herein, the origin of MoSe₂‐electrocatalyzed HER activity monitored by the quasi‐operando XPS and in situ Raman spectroscopy is presented. The findings clearly show dynamic evolution of both Mo and Se species on MoSe₂ electrode surface for promoting HER activity and maintaining long‐term catalytic stability and reveal an electro‐oxidative dissolution and re‐adsorption mechanism. Theoretical calculations also corroborate these results. As expected, the addition of single or mixed MoO₄²⁻ and SeO₃²⁻ to the electrolyte of nickel foam directly verifies the critical role of surface‐adsorbed Mo and Se species for boosting HER activity and stability. Additionally, the oxidative dissolution of Se on Ni_xSe_y electrode surface during HER is also observed, revealing the universality of oxidative dissolution of Se in transition metal selenides. This study provides a unique insight into the species evolution and surface structure transformation mechanism and activity improved origin of materials during the electroreduction process.

A rationally designed and successfully fabricated all-solid-state Z-scheme photocatalyst, CdS/Ag/Bi₂MoO₆, with a sandwich-like multicomponent heterostructure, shows an enhanced photocatalytic performance in RhB degradation.

Photocatalysis with potentially low cost and sustainable utilization is a typically environmentally benign method for the degradation of organic pollutants, but the rational design and fabrication of photocatalysts with high catalytic performance is still an enormous challenge. The efficient segregation of photogenerated electron–hole pairs in photocatalysts is a key and essential factor to decide photocatalytic activity. Herein, a novel Step-scheme (S-scheme) heterojunction photocatalyst, a g-C₃N₄/Bi₂MoO₆ (g-CN/BMO) composite, was successfully fabricated using g-C₃N₄ nanosheet-wrapped Bi₂MoO₆ microspheres. By adjusting the amount of g-C₃N₄ in BMO, a series of g-CN/BMO composites was prepared while optimizing posttreatment temperature. The resulting g-CN/BMO indicated well the photocatalytic performance for the degradation of phenol and hydrogen evolution reactions, especially, 100 g of g-CN was integrated into 100 g of the pre-calcined BMO at 200 °C to produce 100% g-CN/BMO-200, showing the highest photocatalytic performance compared to single composite BMO, BMO-200, g-CN, and g-CN/BMO-200 with other mass ratios. Combining the results from the density functional theory calculations and the results of X-ray photoelectron spectroscopy, for S-scheme heterojunction-structured g-CN/BMO-200, the internal electric field-, band edge bending- and coulomb interaction-driven efficient segregation of photogenerated electrons and holes at the interface is elucidated to explain the photocatalytic mechanism, and the resulting holes on the VB of BMO and electrons on the CB of g-CN are responsible for the improvement of the photocatalytic performance. This study revealed that for the S-scheme g-CN/BMO composite the internal electric field, band edge bending and coulomb interaction at the interface between g-CN and BMO can not only promote the effective segregation of electrons and holes, but also retain stronger redox ability. Such an investigation provides a facile and simple strategy to fabricate novel S-scheme heterojunction-structured photocatalysts for solar energy conversion.

The heterogenization of homogeneous catalysts is a current topic in sustainable chemistry and catalysis. Such immobilized molecular catalysts provide access to environmentally benign chemical syntheses due to the ease of product separation and concomitant waste decrease. This perspective focuses on the fabrication of nanostructured catalysts by using amorphous (non)porous silica or metal oxides and periodic mesoporous (organo)silicas PM(O)S as 1^st and 2^nd generation supports, respectively, as well as metal (silyl)amide complexes as tailor-made grafting precursors. The pertinent SOMC (SOMC = surface organometallic chemistry) places special emphasis on organometallic hybrid materials that display properties distinct from the respective molecular catalysts and on new catalytic avenues which originate from 2^nd generation supports.