Recent Development of SnII,SbIII-based Birefringent Material: Crystal Chemistry and Investigation of Birefringence

The combination of Sn^II or Sb^III with π, non-π-conjugated units has produced birefringent crystals with birefringence ranging from 0.005 to 0.468@1064 nm. It is proven that introducing Sn^II or Sb^III into crystals is a feasible strategy to enlarge the birefringence, which not only promotes the miniaturization of fabricated devices, but also effectively modulates polarized light. Herein, recently discovered Sn^II, Sb^III-based birefringent crystals with birefringence investigated are summarized, including their crystal structure and optical properties, especially birefringence. This review also presents the influence of Sn^II, Sb^III with stereochemically active lone pair on the optical anisotropy. We hope that this work provides a clear perspective on the crystal chemistry of Sn^II, Sb^III-based optical functional crystals and promotes the development of new birefringent crystals with large optical anisotropy.     

Linear Adsorption Enables NO Selective Electroreduction to Hydroxylamine on Single Co Sites

Hydroxylamine (NH₂OH), a vital industrial feedstock, is presently synthesized under harsh conditions with serious environmental and energy concerns. Electrocatalytic nitric oxide (NO) reduction is attractive for the production of hydroxylamine under ambient conditions. However, hydroxylamine selectivity is limited by the competitive reaction of ammonia production. Herein, we regulate the adsorption configuration of NO by adjusting the atomic structure of catalysts to control the product selectivity. Co single-atom catalysts show state-of-the-art NH₂OH selectivity from NO electroreduction under neutral conditions (FE : 81.3 %), while Co nanoparticles are inclined to generate ammonia (FE : 92.3 %). A series of in situ characterizations and theoretical simulations unveil that linear adsorption of NO on isolated Co sites enables hydroxylamine formation and bridge adsorption of NO on adjacent Co sites induces the production of ammonia.