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To systematically investigate the influence of the number of [AO 3 ] layers in the unit cell of hexagonal perovskite oxide on the oxygen evolution reaction performance, we successfully synthesized the three new hexagonal perovskite oxides 2H-BaCo 0.9 Ru 0.1 O 3-δ , 6H-BaCo 0.9 Ru 0.1 O 3-δ , and 10H-BaCo 0.9 Ru 0.1 O 3-δ with the same element composition but different [BaO 3 ] layers via the sol-gel method. Here, 2H, 6H, and 10H refer to the number of [BaO 3 ] layers contained in the unit cell of the BaCo 0.9 Ru 0.1 O 3-δ system. Experimentally, 10H-BaCo 0.9 Ru 0.1 O 3-δ , featuring ten layers of [BaO 3 ], exhibits optimal electrochemical activity among the three oxide catalysts, and in situ Raman results under various bias voltages confirm its ability to maintain a high surface crystal structural stability. Notably, as the number of [BaO 3 ] layers increases, the effective magnetic moments and the valence state of surface Co ions in these three catalysts also increase, with the spin configuration of the surface Co ions being in a high-spin state. More importantly, DFT calculations provide the evolution rules of the p-band center (ε p ) with the number of [BaO 3 ] layers, predicting the electrochemical performance of the BaCo 0.9 Ru 0.1 O 3-δ system with different [BaO 3 ] layers. Our experimental results offer a distinctive perspective for the future design, synthesis, and application of hexagonal perovskite oxides in electrocatalysis.

We present a study on the electrocatalysis of 214-type perovskite oxides LnSrCoO 4 (Ln = La, Pr, Sm, Eu, and Ga) with semiconducting-like behavior synthesized using the sol-gel method. Among these five catalysts, PrSrCoO 4 exhibits the optimal electrochemical performance in both the oxygen evolution reaction and the hydrogen evolution reaction, mainly due to its larger electrical conductivity, mass activity, and turnover frequency. Importantly, the weak dependency of LSV curves in a KOH solution with different pH values, revealing the adsorbate evolving mechanism in PrSrCoO 4 , and the density functional theory (DFT) calculations indicate that PrSrCoO 4 has a smaller Gibbs free energy and a higher density of states near the Fermi level, which accelerates the electrochemical water splitting. The mutual substitution of different rare-earth elements will change the unit-cell parameters, regulate the electronic states of catalytic active site Co ions, and further affect their catalytic performance. Furthermore, the magnetic results indicate strong spin-orbit coupling in the electroactive sites of Co ions in SmSrCoO 4 and EuSrCoO 4 , whereas the magnetic moments of Co ions in the other three catalysts mainly arise from the spin itself. Our experimental results expand the electrochemical applications of 214-type perovskite oxides and provide a good platform for a deeper understanding of their catalytic mechanisms.

Potassium-ion batteries (PIBs) have received much attention as next-generation energy storage systems because of their abundance, low cost, and slightly lower standard redox potential than lithium-ion batteries (LIBs). Nevertheless, they still face great challenges in the design of the best electrode materials for applications. Herein, we have successfully synthesized nano-sized CoSe 2 encapsulated by N-doped reduced graphene oxide (denoted as CoSe 2 @N-rGO) by a direct one-step hydrothermal method, including both orthorhombic and cubic CoSe 2 phases. The CoSe 2 @N-rGO anodes exhibit a high reversible capacity of 599.3 mA h g -1 at 0.05 A g -1 in the initial cycle, and in particular, they also exhibit a cycling stability of 421 mA h g -1 after 100 cycles at 0.2 A g -1 . Density functional theory (DFT) calculations show that CoSe 2 with N-doped carbon can greatly accelerate electron transfer and enhance the rate performance. In addition, the intrinsic causes of the higher electrochemical performance of orthorhombic CoSe 2 than that of cubic CoSe 2 are also discussed., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Objective: To explore the effectiveness of anterolateral thigh fasciocutaneous flap for repair of skin and soft tissue defect and simultaneous Achilles tendon reconstruction with modified methods of ilio-tibial bundle suture., Methods: Between October 2009 and June 2011, 10 cases of Achilles tendon and soft tissue defects were treated. There were 7 males and 3 females, aged from 5 to 60 years (median, 40 years). Injury was caused by spoke in 5 cases, by heavy pound in 3 cases, and by traffic accident in 2 cases. The time between injury and admission was 2-24 hours (mean, 8 hours). The size of wound ranged from 11 cm x 7 cm to 18 cm x 10 cm; the length of Achilles tendon defect was 4-10 cm (mean, 7 cm). Three cases complicated by calcaneal tuberosity defect. After admission, emergency debridement and vacuum sealing drainage were performed for 5-7 days, anterolateral thigh fasciocutaneous flap transplantation of 11 cm x 7 cm to 20 cm x 12 cm was used to repair skin and soft tissue defects, and improved method of ilio-tibial bundle suture was used to reconstruct Achilles tendon. The flap donor site was closed directly or repaired with skin grafting to repair., Results: All flaps and the graft skin at donor site survived, healing of wounds by first intention was obtained. All patients were followed up 6-18 months (mean, 10 months). The flap was soft and flexible; the flap had slight encumbrance in 3 cases, and the others had good appearance. At last follow-up, two-point discrimination was 2-4 cm (mean, 3 cm). The patients were able to walk normally. The range of motion (ROM) of affected side was (24.40 +/- 2.17) degrees extension and (44.00 +/- 1.94) degrees flexion, showing no significant difference when compared with ROM of normal side [(25.90 +/- 2.33) degrees and (45.60 +/- 1.84)degrees] (t = 1.591, P = 0.129; t = 1.735, P = 0.100). According to Arner-Lindhoim assessment method for ankle joint function, all the patients obtained excellent results., Conclusion: A combination of anterolateral thigh fasciocutaneous flap for repair of skin and soft tissue defects and simultaneous Achilles tendon reconstruction with modified methods of ilio-tibial bundle suture is beneficial to function recovery of the ankle joint because early function exercises can be done.