Multi-component tungsten carbide-based hybrid materials featuring different heteroatom dopants coated with X,N dual-doped carbonl ayers (X/W 2 C@X,N-C,X WXNC) were prepared by selecting Keggin-type polyoxometalates (POMs) (NH 4 ) n [XW 12 O 40 ]( X= Co, Si, Ge, B, and P) and dicyandiamide (DCA) as precursors. The electrocatalytic activity of these nanocomposites as counter electrode (CE) catalysts for dye-sensitized solar cells (DSSCs) was systematicallyi nvestigated. Structure characterizations show that X,N heteroatoms were successfully introduced into the W 2 Ca nd carbon frameworks. The obtained X,N dual-dopedc arbon layers were modifieda nd loaded with W 2 Cn anoparticles, promoting the improvement of catalytic performance by as ynergistic effect.T he consequence of photoelectricc onversion efficiency( PCE) is CoWCoNC (6.68 %) > SiWSiNC (6.56 %) > GeW-GeNC (6.49 %) > BWBNC( 6.45 %) > PWPNC (6.20 %) > WNC (6.05 %). With the increase in electronegativity of the dopants, the photovoltaic performance decreases in ar everse order.T his work provides as hortcutt ot he rational design of highly efficient and cost-effective catalysts for DSSCs.

Two series of lanthanide metal–organic frameworks (Ln-MOFs) from two structurally related flexible carboxylate-based ligands were solvothermally synthesized. H3L2 with additional −CH2− group provides more flexibility and different coordination modes and conformations compared with H3L1. As a result, 2-Ln MOFs are modulated from two-dimensional kgd of 1-Ln to three-dimensional rtl topological frameworks and further achieve enhanced chemical stability. The Eu- and Tb-MOFs exhibit strong fluorescent emission at the solid state because of the antenna effect of the ligands. Interestingly, the emissions can be tuned by simply doping Eu3+ and Tb3+ of different concentrations within the Eu x Tb 1–x MOFs. Notably, 2-Ln MOFs realize nearly white light emission by means of a trichromatic approach (red of Eu­(III), green of Tb­(III), and blue of the H3L2 ligand). Furthermore, 2-Ln MOFs also exhibit water stability and demonstrate high selective and sensitive sensing activities toward Fe­(III) and Cr­(VI) in aqueous solutions. The results further highlight the importance of the ligand flexibility on tuning MOF structures with improved structural stability and ion-sensing properties.

The construction of an efficient oxygen reduction reaction and oxygen evolution reaction (ORR/OER) bifunctional electrocatalyst is of great significance but still remains a giant challenge for high-performance metal−air batteries. In this study, uniform FeS/Fe 3 C nanoparticles embedded in a porous N,S-dual doped carbon honeycomb-like composite (abbr. FeS/Fe 3 C@NS-C-900) have been conveniently fabricated by pyrolysis of a single-crystal Fe-MOF, which has a low potential gap ΔE of ca. 0.72 V, a competitive power density of 90.9 mW/cm 2 , a specific capacity as high as 750 mAh/g Zn , and excellent cycling stabilities over 865 h (1730 cycles) at 2 mA/cm 2 when applied as a cathode material for rechargeable zinc−air batteries. In addition, the two series-linked Zn−air batteries successfully powered a 2.4 V LED light as a real power source. The efficient ORR/OER bifunctional electrocatalytic activity and longterm durability of the obtained composite might be attributed to the characteristic honeycomb-like porous structure with sufficient accessible active sites, the synergistic effect of FeS and Fe 3 C, and the N,S codoped porous carbon, which provides a promising application potential for portable electronic Zn−air battery related devices.